ABSTRACT. Our solar system formed from dense clouds of molecular gas and dust about 4.6 billion years ago, and similar star–planetary systems continue to form throughout the Galaxy today. To understand the physical processes of star and planet formation, it is essential to observe the materials from which they form—cold molecular gas and dust grains. With typical temperatures of ∼10–100 K, these components are most effectively traced through emission at millimeter and submillimeter wavelengths.

Star- and planet-forming regions are intrinsically compact, with characteristic sizes of less than ∼1000 au, corresponding to angular scales of only a few arcseconds in nearby star-forming regions. Resolving such small spatial scales requires high-angular-resolution observations with millimeter and submillimeter radio interferometers. Facilities such as the Atacama Large Millimeter/submillimeter Array (ALMA) now allow us to image these regions in unprecedented detail, revealing their complex morphological and kinematical structures.

In this talk, I will present recent observational results obtained with millimeter and submillimeter interferometers, particularly ALMA, and discuss what young stellar objects and their circumstellar disks look like during the earliest stages of their formation.

ABSTRACT. The interstellar medium (ISM) hosts an active complex chemistry, where the interaction between atoms, molecules and dust leads to an exuberantly rich molecular universe. In particular, the interplay between gas-phase and surface-phase chemistry is responsible for the chemical complexity in space and has been mostly derived from radio astronomical observations. Since the discovery of the first molecules in space in the 1950’s, many molecules (some of them considered as complex organic molecules with even prebiotic interest) have been detected in the last decade in very different regions, such as quiescent star-formation environments and the very active and extreme Galactic Centre. This is the case of molecules such as amino acetonitrile, urea or ethanolamine.

The great revolution happened in 2020 with the design and construction of a new Q-band (31-50 GHz) receiver at Yebes 40m telescope with the goal of performing broad band and ultrasensitive submilli-Kelvin level observations with high spectral resolution. This new instrumentation has allowed the detection of nearly 100 new molecules in space in the last five years within the project QUIJOTE, leading to a new golden age in astrochemistry by passing from about 220 molecules in the year 2020 to a total of 340 molecules nowadays. Most of these new molecular species are hydrocarbons and have been found in the cold prestellar cloud TMC-1 where volume density and temperature are rather low. They have sizes from a few atoms (close-shell species, rings, radicals, cations and anions), to more than 30 atoms (CN-derivatives of polycyclic aromatic hydrocarbons; PAHs) which was completely unexpected. Most of these species have been discovered through a solid line by line detection method using the QUIJOTE line survey which reaches an unprecedented sensitivity of 60 μK. Nevertheless, despite this significantly increase of the molecular complexity inventory in the last five years, we are still far away from a realistic understanding of how this molecular variety has been achieved in space.

I will present the QUIJOTE project and review the most recently obtained results, paying special attention on how the new detected molecules help us to shed light on some of the most important questions in Astrochemistry, such as the sulfur depletion problem or the presence of prebiotic chemistry in the ISM and its link with the origin of life. I will also review how the new instruments, such as the new K-band (18-32 GHz) receiver at Yebes 40m telescope and the SKA telescope, will significantly improve our knowledge on interstellar chemistry.

ABSTRACT. The Total Power GPU Spectrometer (TPGS) is a next-generation digital spectrometer for the Atacama Large Millimeter/submillimeter Array (ALMA) Total Power (TP) array. Developed through a collaboration between the Korea Astronomy and Space Science Institute (KASI) and the National Astronomical Observatory of Japan (NAOJ), the TPGS is a key project within the ALMA Wideband Sensitivity Upgrade (WSU). It is designed to replace the existing ACA Spectrometer to meet the high-performance requirements of the WSU era.

The system must handle an aggregate input raw data rate of approximately 3.84 Tbps, consisting of 16 digitized streams (two polarizations and two sidebands from four antennas) sampled at 40 Gsps with 6-bit depth. The TPGS employs an FFX-type signal processing architecture for single-dish observations. This architecture provides a science bandwidth of 32 GHz per polarization with a fine frequency resolution of 13.5 kHz. For interferometric pointing and focus calibrations, the system utilizes a simpler and computationally efficient FX pipeline.

The hardware design utilizes commercial off-the-shelf (COTS) GPU servers equipped with NVIDIA's latest architectures, such as the Blackwell and Vera Rubin generations. To optimize performance, the processing pipeline leverages NVIDIA’s cuFFTDx library, which keeps intermediate data on-chip to minimize memory traffic. Recent benchmark tests on an NVIDIA H100 PCIe GPU demonstrated a throughput of approximately 46 GHz for the fine channelizer.

The software architecture is modular, consisting of the Processing Unit (TPGS-PU), Control Unit (TPGS-CU), Graphical User Interface (TPGS-GUI), and Monitoring Unit (TPGS-MU). This design reuses proven code from the ACA Spectrometer to reduce development risk while introducing new capabilities for real-time monitoring and visualization. Following a successful Preliminary Design Review (PDR) in January 2026, the project is now moving toward the Critical Design and Manufacturing Readiness Review (CDMR).

ABSTRACT. A new cryogenic phased array feed (cryoPAF) has been installed on the Murriyang telescope at Parkes. I will present an overview of commissioning data which demonstrate its capability for the detection of HI and FRBs at cosmological distances. Its low noise temperature (<20K), high efficiency, large number of Nyquist-sampled beams, large bandwidth, high resolution and low chromaticity make it particularly useful for intensity mapping at redshifts up to unity. Results from a new pipeline using higher-order singular value decomposition to remove RFI and residual continuum without impacting redshifted HI cross-power spectrum recovery are also presented.

ABSTRACT. Very Long Baseline interferometry (VLBI) is a powerful technique which provides high-precision astrometric observations. One of its key applications is the construction of a quasi-inertial celestial reference system, known International Celestial Reference System (ICRS), which is realized through VLBI observations of extragalactic radio sources, which are expected to have no physical proper motions and parallaxes. The floor accuracy of current realization ICRF (ICRF3) is limited to 30 μas. Some of the observed radio sources exhibit a persistent astrometric instability due to the physical processes in the central part of AGNs on the scale of several milliarcseconds. This results in a noticeable evolution of the system "core - jet" over the observational history.

We processed all geodetic VLBI observations produced by the International VLBI Service (IVS) during 1993-2025 to study the astrometric instability in the coordinate time series. It was found that 55 radio sources change their apparent positions at the scale between 20 to 130 mas exceeding all the previous expectations. A detailed analysis of the radio images revealed that the detected “jumps” in coordinates are often conditioned by changing source structure – variability of the component brightness and/or physical motion of the relativistic jets. Several radio sources to be known as gravitational lenses with a stochastic evolution of the extended image. We believe the cause of the coordinate changes is variations in the flux density of the image components. For example, the well-known lens 1938+666, representing an Einstein ring, has complex coordinate variations with amplitude up to 350 mas.

ABSTRACT. The origins of cosmic dust remain a mystery, with supernovae (SNe) identified as significant contributors to dust production. Molecule formation following SNe explosions plays a crucial role in this process, as it efficiently cools the ejecta to a temperature suitable for dust condensation. To date, carbon monoxide (CO) molecules have been observed in only a few core-collapse SNe. In this talk, I will talk about CO and dust formation in core-collapse and Type Ia SNe. The paper related to this talk: https://www.nature.com/articles/s41550-024-02197-9

ABSTRACT. While the average polarization profile reveals the large scale magnetic field structure in the magnetosphere, the polarization of single pulses provides new perspectives to study the turbulence level of field structure. We present a systematic study of single pulse polarization of 15 pulsars oberved with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). We found that individual pulses show diverse trends between intensity and linear polarization fraction, with some exhibiting positive, negative or flat/insignificant correlation--with this behavior remaining consistent across frequencies for at least two sources. For pulsars with multiple pulse components, \shaoi{the observed correlation differs significantly between components. Our findings indicate that the level of magnetic field turbulence within the emission region varies across different phase and from pulsar to puslar, potentially in connection with the rotation period. This work demonstrate that the high sensitivity of FAST enables new constraints on pulsar magnetospheric structure.

ABSTRACT. Supernovae are among the most energetic phenomena in the Universe. In the local Universe, Type IIP supernovae (SNe IIP) represent the most common subtype, accounting for approximately 35% of all supernovae. Understanding their origins constitutes a primary scientific objective within time-domain astronomy, and it also greatly advances research in multiple astrophysical fields, such as massive stars evolution, explosion mechanisms, compact object formation, and chemical evolution of galaxies.

In the conventional view, SNe IIP progenitors are extensively interpreted within the single-star evolution framework, which aligns with direct detections of red supergiants prior to their explosions. The significant observed diversity among SNe IIP, however, suggests the existence of different underlying evolutionary pathways. Among these, the scenario involving interacting binary systems was proposed in theoretical studies decades ago and has since been widely investigated. Recent population synthesis models further suggest that about 30–50% of SNe IIP may originate from interacting binary systems. Despite considerable efforts, the binary progenitor scenario still lacks strong observational evidence.

In this talk, I will address this problem by introducing a newly developed methodology. Through a combination of direct detections of the progenitor, analysis of environmental stellar populations, and hydrodynamic modeling of supernova light curves, we confirm that a Type IIP SN originated from a binary merger product. Furthermore, using state-of-the-art binary evolution simulations, we reconstruct the complex interacting processes that the system underwent before merging. This work presents the first compelling evidence for a binary origin of SNe IIP and calls for a reassessment of these most common explosions in our local Universe. The related findings have been accepted for publication in <Science Bulletin> (preview available arXiv:2601.06577).

ABSTRACT. Dark matter (DM) decay is generically predicted in many particle DM scenarios. X-ray band is favorable for warm DM search, including sterile neutrino and axion-like-particle (ALP) DM. Especially, spurious 3.5 keV line excess observed in a stacked or individual sample of galaxy clusters and its DM or atomic origin have been disputed with large uncertainty. Therefore, obtaining independent measurement with less photon background for various celestial object is valuable. Dwarf galaxy Segue 1, given its known extremely high DM-to-light ratio, constitutes an ideal target for detecting DM or obtaining an upper limit. We perform sensitivity studies of decaying DM search with Segue 1 using XRISM and hypothetical detector with 2 eV energy resolution. For 100 ks observation with gate valve closed, XRISM can achieve sensitivity in DM couplings improving by over an order of magnitude compared to the best previous limits from Segue 1 observations by Swift. We also demonstrate that the DM or atomic origin of the spurious 3.5 keV line can be well distinguished if observed by a detector with better than 4 eV energy resolution.

ABSTRACT. The microphysics of cosmic ray (CR) propagation in the multi-phase, magnetised interstellar medium remains unsettled. It is unclear how effectively CRs can excite magneto-sonic waves and regulate diffusion across regions with varying ionisation fractions, densities, and magnetic structures, or how strongly ion-neutral damping suppresses this turbulence to enable ballistic transport in denser regions. These uncertainties complicate efforts to link CR transport to the physical, thermal, and chemical evolution of interstellar clouds, which contribute to persistent discrepancies between theoretical models and observed gamma-ray spectra and ionisation rates in the nearby clouds. Recent measurements of both gamma-ray emission and CR-driven ionisation suggest that CR transport deviates from the idealised limits of purely ballistic or purely diffusive propagation. We therefore develop a self-consistent model of CR transport and interactions in magnetised molecular clouds, examining three propagation regimes: ballistic, diffusive, and a hybrid configuration comprising a diffusive envelope surrounding a ballistic core. Comparison with gamma-ray data shows that the dense component of molecular clouds is mainly diffusive, with any ballistic core confined to regions with small filling fractions of the cloud volume. Our findings indicate that diffusive CR propagation dominates in the dense component of the interstellar medium. This implies that CRs couple strongly with this dense gas, contrary to traditional theoretical expectations.

ABSTRACT. Galaxy kinematics together with structural properties from HST and JWST have revealed that the majority of 'normal' star-forming galaxies at cosmic noon host thick disc-like structures and a turbulent gas-rich interstellar medium. However there exists a significant scatter in the diversity of multi-phase measurements across many epochs which make disentangling the origin of the turbulent motions and the build up of disc structures unclear. Some models postulate that thick discs seen in local galaxies formed early from turbulent discs at z>2, while others are consistent with an early thin disk thickening with time. However, it is unknown how common the two-disc structure of a thick old stellar disc and a thin young stellar disc (e.g. MW, M31) is beyond the local universe. I will present the largest literature compilation of resolved kinematic studies of molecular and ionised gas discs from z=0.5 to z=9 and connect to recent results from JWST on the emergence of the thin/thick disk dichotomy at cosmic noon. When combined with local galactic archeology studies, these results provide new insights into how the structures of local galaxies including the Milky Way were formed.

ABSTRACT. The de Sitter transition scale $a_{dS}=cH$ to anomalous galaxy dynamics was previously derived from first principles based on the background Hubble expansion $H$ and the velocity of light $c$, and shown to be in tension with $\Lambda$CDM galaxy simulations. Tracing late-time cosmology, it predicted the deep-asymptotic acceleration scale $a_0^{th}\simeq 1.66\times 10^{-8}{\rm cm\,s^{-2}}$ without adjustable parameters based on $H$ and the deceleration parameter $q$. A recent weak-lensing determination of $a_0^{WL} = 1.63_{-0.20}^{+0.23}\times 10^{-8}{\rm cm\,s}^{-2}$ now provides an independent empirical test of this prediction. The agreement with the updated theoretical value $a_0^{th} = 1.63_{-0.14}^{+0.13}\times 10^{-8}{\rm cm\,s^{-2}}$ closes the logical chain between cosmology, galaxy dynamics, and asymptotic scaling. Unlike phenomenological fits to rotation curves, this result does not rely on tuning or baryonic modeling but follows directly from background cosmology. This parameter-free model suggests some further tests by galaxy surveys extending over a finite range of redshifts.

ABSTRACT. In the Λ-CDM model, gas and dark matter (DM) mix together within DM haloes. Gas cools down and condenses into the centre of haloes, forming new galaxies. It is natural to assume that gas and DM share identical specific angular momentum (sAM, e.g. Mo et al., 1998).

However, modern cosmological simulations have challenged this assumption. Even in the non-radiative hydrodynamical simulations, removing the effects from radiative cooling and feedback, gas on average has 30%-40% more sAM than DM (Chen et al., 2003; Sharma & Steinmetz, 2005; Zjupa & Springel, 2017). This work reproduces this result by analysing ~50,000 well-resolved DM haloes in a non-radiative simulation. This can be pinned down to the excess angular momentum (AM) of gas in the inner halo, which hints that DM may transfer AM to gas. We uncover the leading driver for this AM difference through a series of control simulations of a collapsing ellipsidal top-hat. These runs reveal that the pressurized inner gas shells collapse more slowly, causing the DM ellipsoid to spin ahead of the gas ellipsoid. The rising torque generally transfers AM from the DM to gas. The amount of AM transferred via this mode depends on the initial spin, the initial axes ratios, and the collapse factor. These quantities can be combined in a single dimensionless parameter, which robustly predicts the AM transfer of the ellipsoidal collapse. This model can explain the average AM excess in controlled and cosmological simulations. Additionally, we find this AM transfer model happens in major mergers of DM haloes, which leads to the gas-to-DM spin ratio change considerably during major mergers. The novelty of this study is that it identifies a mechanism through which AM is exchanged between gas and DM during halo formation and major mergers, and further research is required to extend our understanding to cosmological hydrodynamical simulations with full galaxy formation physics.

ABSTRACT. Strong gravitational lensing is sensitive to the total mass distribution along the line of sight, making it a unique probe of dark matter in galaxies and clusters, and useful for studying resolved properties of the magnified background sources.  Strong lensing is also valuable for constraining cosmology through lensed quasars, which can be monitored to measure the "time delay" between the multiple images and constrain the Hubble constant (H0).  This method of measuring H0 is independent of type Ia supernovae and CMB observations, and may shed light on the H0 tension between local universe and CMB measurements.  The latest results from the TDCOSMO project constrains H0 to be ~72 km/s/Mpc in a flat Lambda CDM cosmology with a precision of ~4.5%.  This result is maximally conservative with respect to galaxy mass profiles, and is consistent with independent determinations of H0 using type Ia supernovae calibrated by the distance ladder method. We present our latest results, as well as our next steps toward increasing the precision of our H0 measurement moving forward.

ABSTRACT. Active Galaxies may be revealed in all spectral ranges and show interesting features from gamma-rays to radio. We will review our recent results on search and studies of active galaxies, both AGN and Starbursts, using all-sky or large-area surveys in X-ray (ROSAT and others), UV (GALEX), optical (SDSS, Gaia and others), IR (2MASS, WISE, IRAS and others) and radio (NVSS, FIRST and others) and based on cross-correlations of different catalogs and samples. Using the homogeneous medium-resolution SDSS spectroscopy, we have carried out fine optical classification for activity types for Active Galaxies (https://www.bao.am/activities/projects/21AG-1C053/mickaelian/). These objects come from a number of samples of some 10,000 candidate Active Galaxies using pre-selection from various samples; bright objects of The Catalog of Quasars and Active Galactic Nuclei, Markarian Galaxies, Blazars, AGN candidates among X-ray sources, IRAS extragalactic objects, including ULIRG and HLIRG candidates, variable radio sources and optically variable radio sources, etc. A number of papers have been published with the results of this spectral classification. The fine classification shows that many QSOs show the same features as Seyferts (subtypes between S1 and S2; S1.2, S1.5, S1.8 and S1.9). We have introduced subtypes for the QSOs: QSO1.0, SO1.2, QSO1.5, QSO1.8, QSO1.9, though the last subtype does not appear in SDSS wavelength range due to mostly highly redshifted H-alpha (the main line for identification of the 1.9 subtype). Thus, independent of the luminosity (which serves as a separator between QSOs and Seyferts), AGN show the same features. Narrow-Line Seyfert 1 galaxies have been classified into subtypes NLS1.0, NLS1.2, NLS1.5, NLS1.8 and NLS1.9. And similarly, Narrow-Line QSOs exist and we have introduced subtypes NLQ1.0, NLQ1.2, NLQ1.5, NLQ1.8 and NLQ1.9 (the last subtypes difficult to identify in SDSS spectra). We also have classified many narrow-line objects as Composites, spectra having composite characteristics between Sy2 and LINERs, Sy2 and HII or LINERs and HII; in some cases, all three characteristics appear together resulting as Sy2/LINER/HII subtype. Moreover, it appears that Composites may contain some broad-line objects as well, such as Sy1.8/LINER, Sy1.9/HII, Sy1.8/LINER/HII, etc. The QSOs subtypes together with Seyfert ones allow to follow AGN properties along larger redshift range expanding our knowledge on the evolution of AGN to more distant Universe represented by QSOs.

ABSTRACT. Astronomy, like biology and geology, is rooted in phenomenology. As such wide exploration (discovery), extensive catalogs (to search for patterns) and modeling (application of physics to explain the patterns) form the backbone of our field. The diversity of astronomical phenomena naturally requires diversity of approaches. Most discoveries are made by small telescopes or focused programs while large telescopes primarily undertake follow up observations. A proper balance between the small, medium, and large, maximizes the output. However, flagship initiatives dominate our collective thinking and funding. However, using successes in time domain astronomy I will show great success can and will come from small projects. However, it is a fact that many small projects fail to deliver. I will present my analysis to distill strategies on making small projects successful. The talk should be useful, particularly for young astronomical research institutions in Asia, as they plan their vision for the future.

ABSTRACT. We investigate the physical origin of the critical mass, a threshold where galaxy properties and scaling relations undergo fundamental transitions, using the Horizon Run 5 simulation. Focusing on massive (Mtot ≥ 10^12M_⊙) central galaxies, we examine the mass-dependent turnover of the stellar-to-total mass ratio (STR) and the physical processes that drive it. We decompose STR as a product of the stellar-to-baryon mass ratio, M∗/M_bar, and the baryon retention fraction, M_bar/M_tot. We find that STR evolution is dominated by stellar-to-baryon mass ratio. We show that a redshift-independent critical mass scale at Mtot ∼ 10^12.5M_⊙ (corresponding to M∗ ∼ 10^10.7M_⊙) naturally arises from the interplay between the baryon cycle and star-formation efficiency. At this mass, a dynamically stable hot gas halo fully develops, strongly suppressing cool gas inflow and making in-situ star formation inefficient. As star formation becomes inefficient, the hot gas reservoir grows while stellar mass accumulation slows, producing an upturn in the gas fraction and baryon retention fraction, and a downturn in stellar-to-baryon mass ratio that drives the STR turnover. Our result places a critical transition in galaxy evolution within a unified physical framework.

ABSTRACT. The Vera C. Rubin Observatory’s Legacy Survey of Space and Time (LSST), due to begin in earnest later this year, will be a game changer in terms of the shere number of transient detections expected. The cadence of this LSST will typically be of order of 2-3 days in any given filter. The next developments after the LSST in transient and variable detections will inevitably push to higher cadences and all sky coverage. In this talk we present the concept of GOTTA: a Global Open Transient Telescope Array. This current concept for this array is for over a hundred 1-m modified Schmidt telescopes, each with a 25 square degree field of view covered by an effective 18k x 18k x 10 micron CMOS camera. Ideally, three telescopes will be grouped together at a single site, each with a dedicated filter allowing for colour determination and elimination of bogus detections. These groups of telescopes will be replicated at many sites in both hemispheres to achieve all-sky coverage, with a cadence of less than an hour for any point on the sky. We describe the concept for the GOTTA project and highlight the science drivers, current status and immediate plans.

ABSTRACT. The cores of globular clusters are some of the densest stellar environments in the Galaxy. Theory and simulations show that this density facilitates a high rate of dynamical interactions, fostering the formation of compact object binaries. However, limited angular resolution and atmospheric seeing prevents ground-based time-domain surveys—which have been very successful at discovering binary systems in the field through periodicity searches—from probing the innermost regions of these clusters. I will introduce a Hubble Space Telescope ultraviolet time-domain survey of the core of 47 Tucanae, one of the brightest and most massive globular clusters in the Milky Way. I will describe exotic compact object binaries found and characterized in the heart of the cluster, with implications for binary evolution, cluster dynamics, and gravitational-wave progenitors.

ABSTRACT. We review the evolution of our understanding of the planetary nebulae phenomenon and their place in the scheme of stellar evolution. The historical steps leading to our current understand-ing of central-star evolution and nebular formation are discussed. Recent optical imaging, X-ray, ultraviolet, infrared, millimeter-wave, radio observations have led to a much more complex picture of the structure of planetary nebulae. The optically bright regions have multiple-shell structures (rims, shells, crowns, and haloes), which can be understood within the interacting winds framework. However, the physical mechanism responsible for the bipolar and multi-polar structures emerged during the proto-planetary nebulae phase is yet to be identified.

Our morphological classifications of planetary nebulae are hampered by effects of sensitivity, orientation, and field of view coverage and the fraction of bipolar or multipolar nebulae may be much higher than commonly assumed. The optically bright bipolar lobes may represent low-density, ionization-bounded cavities carved out of a neutral envelope by collimated fast winds. Planetary nebulae are sites of active synthesis of complex organic compounds, suggesting that planetary nebulae play a major role in the chemical enrichment of the Galaxy. Possible avenues of future advance are discussed.

ABSTRACT. TBC

ABSTRACT. We report the identification of two planetary nebulae, Abell 14 and WKG 3, as potential members of the open clusters HSC 1571 and UBC 295, respectively. Using a comprehensive search across large-scale open cluster catalogues, we investigated the positional and kinematic associations of these nebulae with their candidate clusters. Both nebulae are confirmed planetary nebulae exhibiting characteristic emission-line spectra, notably with elevated [N II] to Hα ratios, consistent with the properties of the known 5 planetary nebulae in open cluster environments. Their potential membership offers valuable insights into the evolution of planetary nebulae within cluster contexts. These discoveries may add to the small sample of PNe associated with open clusters, advancing our understanding of late stellar evolution and the cluster environment's influence on nebular properties. Our findings highlight the effectiveness of large-scale catalogue analyses in uncovering such rare associations.

ABSTRACT. he observation of planetary nebulae NGC 7027 by Merill et al in 1975 across the wavelength range of 2-4 $\mu$m led to the discovery of 2.43, 3.09, 3.27, and broad 3.4 $\mu$m Unidentified Infrared Emission (UIE) features. It was demonstrated that these features could not be reconstructed by considering H I atomic line transitions, which usually dominate this section of typical astrophysical source emission spectra. Higher resolution observations by de Muizon et al. in 1986 and Takunaga in 1991 have also added more UIEs at 3.30, 3.46, 3.52, and 3.56 $\mu$m to this initial discovery. These are now common emission features observed in other planetary nebulae (PNe). We now know that they are the Infrared (IR) signatures of molecular species. Both laboratory experimental data and theoretical approaches confirm that this particular wavelength range of IR spectra is dominated by vibrations of organic molecules, mostly hydrocarbons with various C$-$H bonds. In this talk, we present new diagnostic and specific characteristics of molecular vibrations of various hydrocarbons underpining UIEs within this spectral region and their key role in understanding the chemical nature of UIE carriers. The information embedded in this region of the IR spectra can reveal the missing astrochemical reactions that occur during the evolution of a planetary nebula. Fullerene-containing PNes are a good example of this particular matter. They have rarely been observed within this critical and diagnostic wavelength range. Recently, we have found such a rare example and shown the formation of a significant amount of complex hydrocarbon molecules in fullerene-containing hot and compact PNe, such as M4 18 and thus revealed the complexity of astrochemical reactions in which fullerenes may play a role.

ABSTRACT. With the successive launch of next-generation sky survey projects such as Euclid, LSST, and CSST, astronomical research has entered the era of big data, posing an urgent demand for efficient and interpretable automatic celestial identification methods. Planetary nebulae (PNe), as key products of the late evolution of low- and medium-mass stars, are crucial for studying stellar nucleosynthesis, Galactic dynamics, and cosmic distance calibration. However, the number of known PNe is far lower than the theoretical prediction, and the current identification process is highly dependent on expert experience, which is inefficient and difficult to adapt to the massive data processing needs.

Existing deep learning technologies in astronomical target detection suffer from inherent limitations of "black-box" and poor interpretability, failing to provide traceable reasoning chains required for scientific discovery. To address these bottlenecks, this project aims to construct the first knowledge graph-enhanced multi-agent system (KG-MAS) for PNe interpretable automatic identification.

The core research includes: systematically sorting out and standardizing PNe domain knowledge to build a structured knowledge graph; designing a KG-MAS collaborative reasoning architecture simulating expert teamwork; developing a knowledge-data dual-driven fusion reasoning engine embedded with physics-informed neural networks (PINN) and Bayesian inference for uncertainty quantification; and optimizing the system through real sky survey data verification and human-in-the-loop expert feedback. Currently, preliminary progress has been achieved: the initial construction of the PNe domain knowledge graph is completed with partial expert validation, and a prototype of the KG-MAS collaborative reasoning framework is built. We have tested the system using known labeled samples and achieved good results.

This project breaks through the limitations of existing technologies. With the achieved preliminary results, it will further realize efficient and interpretable full-process PNe identification to expand the PNe sample library, and explore a new paradigm of cognitive astronomical intelligent discovery. It fills the application gap of KG-MAS in astronomical rare target identification, provides a reusable technical template for other celestial identification tasks, and supports the scientific output of next-generation sky survey projects.

ABSTRACT. TBC

ABSTRACT. Recent surveys of nearby galaxies using optical integral field spectroscopy (IFS), in conjunction with more sensitive millimeter-wave facilities for conducting CO surveys, offer new opportunities to study the regulation and quenching of star formation. We describe the Extragalactic Database for Galaxy Evolution (EDGE), an ongoing effort to combine spatially resolved CO data from CARMA and ALMA-ACA with the CALIFA IFS survey, and briefly review recent results. We focus on the well-known scaling relations between molecular gas, stellar surface density, and star formation rate and how they respond to predicted variations in the CO to H_2 conversion factor. The relations found in EDGE-CALIFA are compared with the same relations derived for the ALMaQUEST galaxy sample in a consistent way. We also examine, in a spatially resolved analysis, the CO content of galaxies that have experienced recent changes in star formation rate to place constraints on the agents driving those changes.

ABSTRACT. Polarimetric observations are crucial to understand the properties and the distribution of dust as well as to map the magnetic field orientation in different Galactic environments. Molecular clouds or Star forming regions are the critical sites for studying stellar evolution and understanding the star formation process. I will present a study of the plane-of-sky component of magnetic fields (B-fields) and dust grain alignment in Serpens Main molecular cloud using 850-µm dust polarization observations from JCMT/POL-2. A pixel-to-pixel map of B-field strength is derived using the modified Davis-Chandrasekhar-Fermi (DCF) method. An average value of B field strength is found to be 127±88 µG for Serpens Main. Mostly, Serpens Main cloud is supercritical and sub-Alfvénic, implying the subdominance of B-fields over gravity and its dominance over turbulence. Polarization degree decreases with the emission intensity, aka polarization hole. To understand the origin of polarization hole, we perform various analyses, including the variation of polarization degree (P) with gas column density, dust temperature, and polarization angle dispersion function (S). The non-correlation between P and S implies that B-field tangling is not a dominant effect for the observed depolarization. To quantify the effect of grain alignment on polarization hole, we calculate key parameters of grain alignment using the magnetically enhanced radiative torque (MRAT) alignment theory for local physical parameters (gas density, dust temperature, and B), including minimum size of aligned grains ($a {align}$) and strength of magnetic relaxation. We found that P has strong anticorrelation with $a {align}$, revealing that grain alignment loss is dominant source of polarization hole. Additionally, we found the evidence of MRAT mechanism.

ABSTRACT. The First Large Absorption Survey in HI (FLASH) is an ongoing wide-field ASKAP survey designed to uncover a substantial new sample of neutral hydrogen (HI) absorption systems at intermediate redshifts (0.4 < z < 1.0), covering ~24,000 square degrees of the sky. The survey aims to capture both intervening and associated absorption systems: intervening HI absorption traces the distribution of cold gas along the line of sight toward background continuum sources, while associated absorption probes circumnuclear and host-galaxy gas directly linked to AGN activity. Following the successful Pilot observations, the Full Survey has been underway since 2023 and has already completed more than half of its planned footprint. We outline the current survey progress and present the processed data products, including spectra, continuum images, and catalogues, which are now publicly available. We also highlight a subset of identified absorbers that exhibit a wide range of line widths, column densities, and kinematic structures. We further discuss multiwavelength follow-up efforts that resolve the small-scale distribution of cold gas in selected cases. By comparing the absorption properties with host galaxy characteristics from complementary optical spectroscopy, we investigate how these systems trace gas reservoirs associated with AGN activity. These results extend our census of HI absorbers to higher redshifts and deliver key groundwork for future large HI surveys with the SKA.

ABSTRACT. We have obtained multi-wavelength data including radio observations and keck spectroscopy of a nearby galaxy group with at least 9 members. The most intriguing aspect of this galaxy group is the presence of two spiral galaxies in close proximity and of a similar stellar mass, but with vastly different HI masses. The HI-excess spiral is a polar ring galaxy with extended spiral arms, and the HI-deficient spiral is a more compact, high surface brightness galaxy with potentially up to ~3x higher star formation rate. The existence of two such spiral galaxies in the same environment, with similar stellar mass but vastly different morphology and HI masses, shines a light on the processes governing galaxy formation. We find the angular momentum of the galaxies was critical to their star formation properties. This detailed study illustrates the need to understand the physical processes in groups that give rise to the various scaling relations we observe.

ABSTRACT. We present the Atacama Large Millimeter/submillimeter Array Band 7 observations of the H$^{13}$CO$^{+}$ and C$^{17}$O molecular line emissions toward the Class 0 protostar HH 212 and compare them with the HCO$^{+}$ line emission reported in the literature. We find that C$^{17}$O and H$^{13}$CO$^{+}$ trace the envelope up to a radius of $R\sim800$ au, while HCO$^{+}$ shows a more compact envelope within $R\sim400$ au, resulting from differences in abundance, opacity, and dynamical conditions. H$^{13}$CO$^{+}$ and C$^{17}$O are optically thin within these observed radii, whereas HCO$^{+}$ is optically thick and also highlights the collimated jet and outflow cavity walls. Through non-ideal MHD simulations, we find that C$^{17}$O exhibits a radial velocity drift of $\sim$0.5 km s$^{-1}$ with respect to the ionized molecules, consistent with ambipolar diffusion, in which the magnetic field, tied to the ions, lags behind during collapse. The ambipolar diffusion fraction ranges from 0.3 to 1.5 depending on the magnetic field strength, and the Hall parameter varies between 0.1 and 7, indicating weak to moderate coupling between charged particles and the magnetic field.

ABSTRACT. Cosmic rays are high energy particles or gamma rays from space, and pose an important hazard to humans and instruments in space. Key populations include solar energetic particles of energies up to the GeV (10^9 eV) range accelerated by occasional solar storms, which are associated with numerous “space weather” effects on human activity, and a continuous flux of more energetic Galactic cosmic rays. The acceleration and transport mechanisms relate to space plasma processes, especially turbulent magnetic fluctuations. I will briefly summarize our design and construction of high energy particle detectors for the Chang’E 7 & 8 lunar missions, and results from ground-based detectors that we operate in Thailand and Antarctica. Based on our analyses of solar energetic particle data, as well as public data from NASA’s Parker Solar Probe, it can be concluded that solar energetic ions are predominantly accelerated at interplanetary shocks, their interplanetary transport is nearly scatter-free within the solar wind’s Alfvén surface, and then they are scattered by intense slab fluctuations near Alfvén surface, finally experiencing weaker scattering and longer mean free paths at 1 au and beyond. Turning to higher energies, as part of the LHAASO Collaboration that operates huge cosmic ray detector arrays in China, we have for the first time discovered solar storm effects on TeV (10^12 eV) range Galactic cosmic rays. The origin of Galactic cosmic rays up to ~1 PeV (10^15 eV) has long been attributed to supernova remnants. Now high-precision LHAASO data allow the determination of spectra of individual cosmic species, for protons and helium, identifying the spectral “knee” in each population at multiple PeV. The sources of these super-PeV populations may be associated with Galactic PeV gamma-ray sources identified by LHAASO, including microquasars.

ABSTRACT. We investigated correlations between cosmic-ray intensity and 14 solar and interplanetary parameters, which were classified into four cases. We used the modulation of cosmic-ray intensity observed at six distinct stations with different latitudes and cut-off rigidities. We used the partial least squares (PLS) method to rank the parameters. In the first case, we employed 11 parameters without considering halo-type coronal mass ejections (CMEs) and solar proton events (SPEs). In addition, we considered energetic phenomena associated with halo CMEs for the second case and SPEs in the third case. In the fourth case, we combined all of the parameters. The results based on the magnitude of the first principal component show that the sunspot number (SN), interplanetary magnetic field (IMF), heliospheric current sheet (HCS), and plasma velocity are the parameters with the strongest influence on the modulation of the cosmic-ray intensity at all six stations and in the first case we considered. For a halo-type CME (second case), SN, IMF, HCS, CME speed, and proton density were identified as the most significant parameters, which is identical to the results obtained in the fourth case. During an SPE (third case), the most significant parameters were SN, IMF, HCS, SPEs, and plasma velocity. The INVK and OULU stations, with nearly the same latitude and altitude, exhibit similar results. Our analysis of the results from the low-latitude stations (PSNM and TSMB) yielded different results from the other three stations at higher latitude. For the PSNM and TSMB stations, By, Bx, and the cone angle are the parameters that most strongly influence the modulation of the cosmic-ray intensity. This occurs because the influence of these parameters on cosmic-ray modulation depends on the latitude.

ABSTRACT. The X-ray binary systems (XRBs) consisting of a strongly magnetic neutron star (NS) accreting from a companion star of spectral type Be form the Be/X-ray binary (BeXRB) subclass of high-mass X-ray binaries(HMXBs). We conduct timing and spectral investigation of the accretion-powered Be/X-ray binary, XTE J1829-098, by using three Nuclear Spectroscopic Telescope Array (NuSTAR) observations from 2018 and 2024. X-ray pulsations at ∼ 7.8 s were observed during the three observations, and the pulse profile followed an asymmetric sine-like shape. The 3–40 keV continuum is well described with a cutoff power-law, an Fe Kα line at 6.4 keV and cyclotron resonant scattering feature (CRSF). In our investigation, we discovered that the structure of fundamental CRSF is complex and cannot be properly accounted for by adding a single absorption component to the continuum model. The complicated CRSF structure can be modelled using either double anharmonic CRSFs at ∼ 14 keV and ∼ 17.4 keV or a CRSF at ∼ 14 keV with a red wing. Both models provide comparable fits and are difficult to distinguish. In this talk, I will discuss the possible physical scenarios for the applicability of each model. Furthermore, I will highlight how this work can help us figure out the complex structure of cyclotron lines in other pulsars.

ABSTRACT. We investigate a unified cosmological scenario within symmetric teleparallel gravity by considering a non-minimal matter–geometry coupling in f(Q,Lm) gravity. Using a minimal polynomial form of the gravitational function, we show that both early-time inflation and late-time cosmic acceleration naturally emerge as different curvature regimes of the same geometric theory.

At late times, the matter–geometry coupling governs the background expansion. By modeling dark energy through holographic Ricci dark energy, we reconstruct the cosmological dynamics and obtain a stable accelerating expansion consistent with observations. A Bayesian analysis using Pantheon supernovae, cosmic chronometers, and DESI 2024 BAO data indicates that current observations provide only a one-sided constraint on the coupling parameter, remaining compatible with the minimally coupled limit while allowing mild deviations.

In the high-curvature regime relevant to the early Universe, the quadratic non-metricity correction dominates and produces a Starobinsky-like inflationary phase driven entirely by geometry. The predicted spectral index and tensor-to-scalar ratio fall well within current CMB constraints.

We further examine Planck-scale effects by incorporating quantum-gravity-motivated corrections through a momentum-dependent deformation of the spacetime metric. These modifications alter the effective inflaton sector while preserving the classical background evolution, leading to small but finite shifts in higher-order inflationary observables.

Overall, this framework provides a geometrically motivated and observationally viable model capable of explaining inflation and late-time acceleration within a single theory while remaining stable under controlled quantum corrections.

ABSTRACT. Understanding the baryon cycle and chemical enrichment in the Universe requires access to galaxy populations that are largely invisible in conventional optical surveys. In this talk, I will present recent progress in uncovering such hidden components of galaxy evolution by combining radio, millimeter, and submillimeter observations.

First, I will discuss new constraints on the cosmic origin of fluorine using hydrogen fluoride (HF) as a tracer. Recent observations toward a gravitationally lensed dusty star-forming galaxy at z=6.02 place stringent upper limits on the HF abundance, indicating that fluorine enrichment was still inefficient only ~1 Gyr after the Big Bang. These results provide a unique probe of nucleosynthesis pathways and suggest that dominant production channels, such as contributions from Wolf–Rayet stars or AGB stars, were not yet fully established at this epoch.

Second, I will introduce a large-area survey of radio-detected AGNs based on Subaru-HSC in combination with VLASS and LOFAR. This approach enables a systematic census of accretion activity across cosmic time, including heavily obscured systems that are often missed in optical and X-ray surveys. The synergy between deep optical imaging and wide-field radio data provides a powerful means to identify and characterize the co-evolution of galaxies and supermassive black holes.

Third, I will highlight the emerging population of near-infrared dark galaxies identified using ALMA and JWST. These systems, faint or undetected even in deep near-infrared imaging, likely represent a key phase of rapid, dust-obscured star formation. In particular, we are conducting systematic surveys of lensing clusters, including ALCS and VENUS, to efficiently identify and characterize such obscured populations. I will present some selected recent results, including an H-band dropout galaxy in a gravitationally lensed galaxy group at z = 4.3, where [C II] 158 um observations reveal intense star formation activity hidden from traditional surveys.

Finally, I will argue that a comprehensive understanding of these obscured populations requires wide-band, multiplexed spectroscopic capabilities at millimeter and submillimeter wavelengths. In this context, I will discuss the potential of integrated superconducting spectrograph (ISS) technology. In combination with next-generation large-aperture submillimeter facilities such as AtLAST/LST, this approach will enable transformative, large-scale spectroscopic surveys, opening a new window on the co-evolution of gas, dust, metals, and black holes across cosmic history.

ABSTRACT. Cosmic filaments host a large fraction of galaxies and influence their formation and evolution, yet the filament network and its links to galaxy properties remain uncertain, particularly at high redshift. We present a two-step study that first delivers a robust filament identification framework and catalogue, and then uses this filament sample to quantify the internal galaxy distributions of filaments over cosmic time. Using the COSMOS-Web Data Release 1 deep-field catalogue, we construct a filament catalogue over 0.5<$z$<3.5 (extending to $z\sim$3.6). We develop a DisPerSE-based method that explicitly incorporates photometric-redshift probability distribution functions (PDFs): within each tomographic 2D slice, we generate multiple galaxy realizations by sampling the photo-$z$ PDFs, stack the resulting skeletons to build "filament probability maps", and extract filaments from these maps. We calibrate the extraction parameters with mock catalogues from the TNG300-1 simulation by minimizing discrepancies between 3D filaments and their 2D-projected counterparts. We detect 20,318 filaments and associate galaxies with $M_\star$>$10^{8.2}\ M_\odot$ to their nearest filaments, yielding both filament and galaxy-filament catalogues. Comparisons to simulations show good agreement in key properties, supporting the physical robustness of the extracted network. Building on this filament sample, we combine deep multi-wavelength COSMOS data with SDSS to characterize projected (2D) radial profiles of prominent filaments, traced by galaxy number density and stellar-mass density. The average radial slope varies with distance from the filament spine and reaches a minimum at a characteristic radius, suggestive of a natural filament boundary analogous to halo splashback. Similar profile shapes are found in TNG300, which further enables consistent 3D profile measurements. The presence of this characteristic scale and its evolution with redshift imply that filaments grow approximately self-similarly and become increasingly concentrated with time.

ABSTRACT. Based on deep Chandra data, we measured the X-ray-derived abundances of Si, S, Ar, Ca, and Fe in Wolf-Rayet (WR) stars from the NSC, Arches and Quintuplet clusters and a field source. Spectral fitting assumes a WR wind composition (H-depleted, C/N-enriched). The Arches and Quintuplet stars show similar Si, S, and Ar abundances but distinct Ca and Fe values, potentially due to dust depletion in Quintuplet. The overall near-solar or subsolar metallicity of the winds suggests internal nucleosynthesis and mixing from parent stars that initially had supersolar metallicity, consistent with the Galactic Centre environment. These results impact our understanding of the region's young clusters and the composition of accretion flow onto Sgr A*.

ABSTRACT. High-frequency quasi-periodic oscillations (QPOs) of Galactic black hole X-ray binaries in the frequency range of ~40–450 Hz are believed to arise in the inner region of the accretion disc, very close to the innermost stable circular orbit. For a given source, the QPO frequencies are remarkably stable over multiple epochs, suggesting a connection to fundamental properties of black holes, such as mass. Observationally, this connection is supported by the empirical scaling relation between frequency and black hole mass established for stellar-mass black holes. By extrapolating this relation to supermassive black holes, high-frequency QPOs in active galactic nuclei (AGNs), equivalent to those of black hole X-ray binaries, are expected at submillihertz frequencies. The first submillihertz QPOs were detected from the narrow-line Seyfert 1 galaxy RE J1034+396. Evidence for submillihertz quasi-periodicity has been reported for a few other AGNs, suggesting the same underlying QPO mechanism across stellar to AGN black holes. Similarly, intermediate-mass black holes (IMBHs), which represent an important link between stellar and supermassive black holes, are expected to show high-frequency quasi-periodicity at tens to hundreds of millihertz. However, high-frequency QPOs from active IMBHs have not yet been reported. Here, we present observations of a stable on long timescales quasi-periodicity in the rest-frame UV flux of the intermediate-mass black hole candidate, AGN ULAS J081621.49+213442.65 at z=7.453. ULAS J081621.49+213442.65 is an intrinsically faint object (with an absolute magnitude of M2600≃-16.72 mag), extremely magnified by more than 1000 times. The continuum luminosity, corrected for lensing magnification, and the width of the MgIIλ2799 line suggest a central black hole in the intermediate-mass range of ∼4×10^4-9×10^5 M⨀. The periodogram analysis of the light curves indicates quasi-periodicity at two distinct frequencies, ∼47 and 38 mHz in the rest-frame of this object, with a frequency ratio similar to that of the Seyfert 1 galaxy RE J1034+396. Assuming a similar mechanism of quasi-periodicity as that of RE J1034+396, the QPO frequencies of ULAS J081621.49+213442.65, which are more than 100 times higher, suggest a black hole mass smaller by a factor of 100, i.e., only a few times 10^4 M⨀. Thus, independent of luminosity and spectral properties, the quasi-periodicity of ULAS J081621.49+213442.65 indicates an intermediate-mass black hole in this object. ULAS J081621.49+213442.65 may be just one example of the expected but largely undetected population of actively accreting intermediate-mass black holes, thought to be progenitors of the first supermassive black holes at high redshift.

ABSTRACT. We measure the luminosity function (LF) of the Milky Way's stellar halo, using a magnitude complete, distance limited sample of stars from Gaia DR3. Stars with high transverse velocities are selected, to isolate a high purity sample of the local halo. We adopt a cutoff transverse velocity of 250 km/s, yielding 24,471 stars, and compute the halo LF, taking into account the effects of sample selection criteria. The LF displays similar features as are found in the well-probed LF of nearby, metal-rich disk stars, showing a strong peak at an absolute magnitude of around M_G = 10, and a flattening near M_G ∼ 7 (Wielen dip). The Gaia sample yields the first measurement of the LF continuously from the dimmest main sequence halo stars (subdwarfs) at an absolute M_G magnitude near 13 mag to bright giants at M_G ∼ −3. We obtain a local stellar halo number density of 1.7 x 10**−4 stars/pc**3 and disk-to-halo ratio by stellar number density of 480:1. We convert the Gaia G-band measurements for our sample stars to Johnson-Kron-Cousins V band, compute the V-band halo LF, and compare it to previous studies published over many decades that cover a wide range of techniques used. We discuss applications of the LF to the measurement of the luminosity and stellar mass of the Milky Way halo.

ABSTRACT. TBC

ABSTRACT. Time-domain astronomy has transformed our view of the dynamic universe by enabling the discovery and characterisation of rapidly evolving astrophysical phenomena across multiple messengers. Coordinated observations across the electromagnetic spectrum, together with gravitational-wave detections, provide powerful constraints on the physical processes driving cosmic explosions and relativistic outflows, as well as their environments.

In this talk, I will highlight how rapid identification, multi-wavelength follow-up, and high-cadence monitoring are essential for capturing the temporal evolution of transients and uncovering their underlying physics. I will discuss the importance of prompt response in the multi-messenger era, and the contributions of Indian observatories to this effort—particularly their role in rapid follow-up and sustained time-domain monitoring—demonstrating their growing impact in coordinated campaigns. I will also briefly discuss recent data-driven approaches, including machine learning techniques applied to time-domain datasets for classification and physical inference.

ABSTRACT. Flare flux reflect contribution from active regions rather than the whole hemisphere of a star. Unlike the amplitude of light-curves caused by starspots, the flare detection is independent of inclination, and the observational properties of flares relies on the location information on the hemisphere. The two valuable properties of flares can be used to reveal the latitudinal distribution of active regions (LaDAR) given that LaDAR is coupled with inclination and location information in spatially unresolved stars. We detected ∼ 27000 flares of 1510 flaring stars in the TESS mission with the corresponding inclinations obtained. The detection rate of flaring stars shows that flares are hard to detect on stars with low inclination, indicating that flares occur mainly at low latitudes. Further investigation of the relationship between the apparent flaring activity and inclination along with the rotation period finds that as the rotation period increases from a solar-like rotation to an ultra-fast rotation, the mean latitude of active regions increases from θ ≈ 15◦ to θ ≈ 27◦, whose trend is in line with the rotation–activity relationship. The LaDAR indicates that flares are attributed to small-scale fields that are formed at low latitudes, while polar spots that are associated with large-scale fields are inactive and are difficult to trigger flares.

ABSTRACT. Roman Space Telescope (formerly the Wide-Field Infrared Survey Telescope or WFIRST) is a NASA infrared space telescope scheduled to launch by May 2027. Wilson et al. (2023) predicted that Roman will find between 60000 and 200000 transiting planets. Through the simulated photometric uncertainties, the detectability of transiting exomoons with various configurations hosted by these transiting planets will be investigated and presented. In addition, known exoplanets with publicly available TESS data will be employed as a testbed for our detection method.

ABSTRACT. Understanding the mechanisms that cause some AGB stars to pulsate remains an open problem. It should be possible to determine precisely the location of the instability region(s), both in the Hertzsprung–Russell diagram and, more simply, in the initial mass–age plane, as has been done for Cepheids. At present, however, this is not yet the case. In principle, when a star pulsates, the way it does so depends more on the physics governing its interior than on what happens in its atmosphere. However, what happens in its atmosphere has a strong impact on the appearance of the light curve. We present considerations aimed at assessing the extent to which the study of light curves of pulsating stars may serve as an efficient tool for understanding the inner dynamics. Using well-measured light curves of pulsating AGB stars, we define parameters that characterize their main features in more detail than has been previously done and reveal correlations between these and parameters describing the state of the star, such as the colour index, the temperature, the possible presence of technetium in the spectrum, the spectral type, etc... At the same time as significant progress has been achieved, the complexity of the problem prevents drawing a clear and reliable picture of the precise relation between the evolution of a pulsating star along the AGB and the main features displayed by the light curve.

ABSTRACT. The theory of stellar atmosphere has been established since 1970s. Since then, the basic ideas of modeling the atmosphere of a star are more or less the same, i.e. relying on the radiative transfer equation and a number of equilibrium equantions and conservation equations. In principle, this heavily relies on statistical mechanics. However, a number of issues are still difficult to be considered, such as at which point we should turn from NLTE to LTE or other way round, how to deal with convective moving and megnatic field, how to deal with mass ejection or accretion. These complicated activities are not in equilibrium and call for a novel methodology to model the whole atmosphere. Thanks to the blooming of the AIs and the computing power, we have an opportunity to test a completely new idea to model the atmosphere of a star in ab initio sense. I will demonstrate how to simulate the physical process, such as photon-atom-electron interactions, in microscopic scale, within acceptable time, and how to build up the whole stellar atmosphere from these micro-blocks. In this way, all inequilibrium would be directly introduced to the model and provide a more extending and open future of the modeling of radative transfer process.

ABSTRACT. After exhausting hydrogen in the core, star arrives in the giant branch where its size increases and convection sets in the outer envelope which leads to various structural and chemical changes in the stars. Conservation of angular momentum predicts very low surface rotation in the giant star and convection alters surface composition of the stars, remarkably reduces Li abundances. Majority of the stars follows these predictions of standard stellar models, however fraction of stars exists with abnormally high rotation and/or excessively high Li abundance, thousands of time more than prediction. Previous studies, using asteroseismic technique, has constrained evolutionary phase of Li enhanced giants as red clump, physical mechanism responsible for Li production is still unknown. Recently binary merger as a Li production site has been proposed but no observational evidence are available. In this study we found, large fraction (40 %) of freshly Li-enriched stars (A(Li) > 3.3 dex) are rapidly rotating and with dilution of Li abundance fraction of rapidly rotating Li-rich giants decreases (5 %). This can be direct consequence of spin up after binary merger and subsequent spin down. With high rotation, post binary merger stars can also have anomalous carbon-to-nitrogen abundance ratio and extreme low mass. We discovered that Li rich giants are 12 times more frequent in anomalous [C/N] ratio stars and 8 times more frequent in the extreme low mass stars. These findings indicate that binary merger in red giant branch is the key reason behind Li enhancement in low mass stars. Our work also suggests that only a small fraction of red clump stars, which are progeny of binary merger, become Li-rich which is in contradiction of previously proposed hypothesis that all red clump stars are Li-rich. With this I will also discuss AGB/upper RGB stars with excess Lithium in this talk.

ABSTRACT. This project presents a study of 12 relatively poorly explored planetary nebulae with bubble-like morphologies, based on long-slit spectroscopic observations and complementary imaging data. High-dispersion spectra are used to derive kinematic parameters and to construct three-dimensional morpho-kinematic models. Low-dispersion data provide spatially resolved determinations of electron temperatures, densities, and ionic abundances across different regions of each nebula. This work seeks to examine whether systematic trends or consistent relationships may exist between morphology, kinematics, and physicochemical conditions within this morphological class. Observations were obtained using the MEZCAL and Boller & Chivens spectrographs at the San Pedro Mártir Astronomical Observatory, Mexico. Future work will incorporate additional imaging and multi-wavelength data, as well as objects reported in the literature, in order to expand the sample and strengthen the comparative analysis. This study contributes to a better understanding of the processes that shape planetary nebulae and the physical mechanisms governing their late evolutionary stages. Acknowledgements: FSB is in grateful receipt of SECIHTI graduate scholarship. This work was supported by UNAM-DGAPA-PAPIIT grant IN103125.

ABSTRACT. The Perseus molecular cloud represents an ideal target for studying the fundamental properties of young stars and their environment since the complex is sufficiently nearby Consisting of an elongated chain of dark clouds, Perseus spans over an area of 7° × 3° in the plane of the sky. The most prominent substructures are Barnard 5 (B5) and IC 348, at the eastern edge and Barnard 1 (B1), NGC 1333, L1448, L1451, and L1455 at the western edge of the complex. Machine learning is an effective method used for membership determination.

The Perseus molecular cloud is a nearby (~300 pc) area of size 6 by 2 degrees and includes the young star-forming clusters IC 348 and NGC 1333, both of age 1-3 Myr lying within 300 pc of the Sun. With Himalyan Chandra Telescope observations of IC~348 and NGC~1333, coupled with Spitzer c2D Survey, WISE and 2MASS data we compile a catalog of YSOs in the region. We use this catalog to crossmatch with Gaia DR3 data to produce a control sample. We then use machine learning techniques DBSCAN, OPTICS and HDBSCAN to identify a new population of YSOs. We classify them into 9 clusters and find their positions and velocities. We study all these regions and We classified these objects using 2MASS and WISE data to study their distribution and the progress of star formation in Serpens using the kinematical data from Gaia DR3 to study this large region. In this paper, we analyse and obtain parameters, masses and IMF of IC 348 and NGC 1333 using HCT data. It was found that neither cluster exhibits mass segregation nor do the most massive stars reside in areas of enhanced stellar surface density compared to the average surface density. We also study the spatial distributions and kinematics of these clusters with reference to the other clusters present in the Perseus cloud using Gaia DR3 data to ascertain if these clusters formed by triggered star formation.

ABSTRACT. With gigantic telescopes on the drawing boards to gradually on the horizon, small telescopes strive with focused or complementary scientific topics. Here we report a 2-m optical/infrared telescope to be installed at the San Pedro Mártir Observatory (SPM), in Baja California, Mexico, with a joint effort by National Central University (NCU), and Universidad Nacional Autónoma de México (UNAM), i.e., a trans-Pacific collaboration, plus other partners such as the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Shanghai Astronomical Observatory (SHAO), Henan Academy of Science (HNAS), and Aix-Marseille Universit (AMU). This TP2m telescope is equipped with instruments to response effectively cosmic transient phenomena, e.g., a simultaneous multiband imager, and a spectrograph for quick follow-up classification, particularly the events suspected by the Legacy Survey of Space and Time (LSST) project carried out at the Rubin Observatory atop Cerro Pachón in northern Chile. The TP2m, located in a time zone 3 hours behind Rubin, sits in the front row to respond to LSST alerts with first timing “to secure the discoveries”. There is also synergy with the Colibri telescope also at SPM to pursue the alerts triggered by the SVOM satellite, and with the telescopes at Lulin in Taiwan for bright events. We will outline the key parameters of the TP2m components, such as the telescope, instruments, robotic operations, time allocation and coordinated queue scheduling strategy, alert responses, the status of the project as well as forward planning. The TP2m facility is expected to see the first light in 2027.

ABSTRACT. The Deep Synoptic Array-2000 (DSA-2000) is a next-generation facility that will provide a sensitive all-sky radio survey at declination > -38 deg, complementing other multiwavelength all-sky surveys (e.g., Rubin/LSST, Roman, eROSITA, Euclid, Sphere-X, UVEX). The DSA-2000 will operate between 0.7 - 2 GHz, with a 3" PSF at 1.35 GHz. The capabilities of the DSA-2000 are optimized to deliver a survey speed 10x faster than any current radio telescope, as well as a sensitivity comparable to the most sensitive current radio telescopes (i.e., 1.6 Jy SEFD at zenith). Key surveys are currently planned for 2029 - 2033, and will include the commensal operation of two back-end instruments: the Radio Camera (imaging) and the Chronoscope (time-domain). Science-ready data products will be available to the public immediately, with no proprietary period. In this talk, I will discuss the current status of the DSA-2000 Chronoscope back-end, focusing on the challenges and science goals unique to fast radio bursts (FRBs). The DSA-2000 is currently projected to discover and localize 20,000 FRBs/yr. Such a large sample will be transformative both for understanding the origins of these enigmatic transients, as well as for using them to understand the distribution of diffuse matter in the Universe.

ABSTRACT. The Chinese Space Station Survey Telescope (CSST or XunTian) is China’s first 2m-class serviceable space telescope. As the flagship science mission of China Manned Space program, it will follow the Tiangong Space Station Complex in the same 400km-height inclined orbit with large phase difference beyond -10 degree. The telescope can change its orbit phase and dock with the Complex for in-situ maintenance by well-trained taikongnaut crew who will perform extravehicular activities for repairing or upgrading components including science instruments (SI). CSST’s Survey Camera for broad sciences in astronomy, with multi-band imaging and slitless spectroscopy, fulfills the primary mission of large area wide-field survey and specified deep-field. The 9K*9K 4-side buttable CCD prototype covering near-UV and visible bands, newly developed by CETC, were assembled into the camera’s qualification model with e2v’s counterparts in 2024. Since then its parallels to fight products have been substantially improved in dark current, CTE,etc. Extensive qualification tests and production validation review have been achieved, so far the CCD flight product almost completes acceptance test for final delivery. Filters, grating units and other components were tested with CCD sensors simultaneously, then integrated for instrumental overall test. All qualification models of the camera and other instruments were assembled into the optical telescope assembly (OTA). System-level optical performance were verified in thermal vacuum chamber, such as PSF and sensitivity. However, close examination revealed that contamination had been accumulated during the assembly, integration and testing (AIT) procedure. Stringent contamination control is being implemented throughout the flight-model AIT activities from components to system.

ABSTRACT. During this talk, I will describe the current and future capabilities of CSIRO’s Australia Telescope National Facility (ATNF). CSIRO is Australia’s national science agency and the ATNF is one of the world’s most advanced radio astronomy facilities – the only major facility of its kind in the southern hemisphere, offering a unique view of the sky across a broad radio spectrum. The capabilities of the ATNF’s key and iconic instruments will be outlined, such as the Australia Telescope Compact Array (ATCA), the ASKAP radio telescope, the Long Baseline Array and Murriyang, the Parkes radio telescope. I will also describe our data archiving facilities, hosting 15 PB of data, and current data processing tools. There will be highlights from recently commissioned systems including the cryogenically cooled phased array feed receiver for Murriyang and the ATCA rapid-response transient observing mode, which makes it the fastest responding gigahertz-band telescope in the world. I will describe the means to obtain observing time on these facilities, including the option to purchase telescope time. During the presentation, I will also mention future possibilities including low-frequency Very Long Baseline Interferometry (VLBI) and ultra-wide-bandwidth receivers for Murriyang.

ABSTRACT. Malaysia is developing a new regional astronomical facility known as the Pusat Astronomi Borneo (PAB), located in Santubong, Sarawak. Designed as a upcoming dual-purpose observatory for optical and radio astronomy, PAB represents Malaysia’s emerging commitment to building scientific infrastructure that supports both frontier research and sustainable community development. Similar to other new observatories in Southeast Asia, the establishment of PAB carries multidimensional impacts scientific, educational, environmental and socio-economic especially as it is situated near rural communities and tourism ecosystems. The objective of this paper is to present the development of Pusat Astronomi Borneo (PAB) as a sustainable ground-based observatory that strengthens Malaysia’s capacity in optical and radio astronomy while promoting environmental responsibility and alignment with the United Nations Sustainable Development Goals (SDGs). In parallel, the observatory promotes space sustainability awareness, focusing on basic strategies of spectrum management, light pollution mitigation and responsible development to ensure that future observational activities remain environmentally and scientifically viable. Beyond its scientific value, PAB embodies Malaysia’s contribution to the United Nations Sustainable Development Goals (SDGs), particularly SDG 4 (Quality Education), SDG 8 (Decent Work and Economic Growth), SDG 9 (Industry, Innovation, and Infrastructure), SDG 13 (Climate Action), and SDG 17 (Partnerships for the Goals). The establishment of PAB thus reflects a holistic model of sustainable astronomical infrastructure linking scientific advancement with education, community development, and environmental stewardship for the future of astronomy in Borneo and the wider Asia-Pacific region.

ABSTRACT. A modern interpretation of the asteroid hazard problem includes the requirement for the extensive detection of asteroids larger than 10 m. Currently, the detection completeness for 50 m bodies does not exceed 1%, while for 10 m bodies it is close to zero. 10 m class asteroids hit the Earth approximately every 10 years, while close passages through near-Earth space occur much more frequently. Collisions with 10-50 m asteroids pose a significant threat on a timescale comparable to a human lifetime, therefore, they are the primary target for upcoming detection systems. These small bodies are faint, therefore they are observable at short distances. Approximately half of them approach the Earth from the daytime sky and can only be detected by special space-borne facilities. In 2025, the promising Russian national asteroid-hazard program, as a part of "Milky Way" completed its System Requirements Review (SRR) phase. The program proposes launching a dedicated spacecraft to the Sun-Earth L1 Lagrange point (SEL1). The spacecraft is being designed by the Lavochkin Association. The payload is divided into two parts. The first, named SODA (System for Observation of Daytime Asteroids), is responsible for detecting asteroids larger than 10 m coming from the sunward direction, which cannot be observed by ground-based or near-Earth space telescopes. It has been under development at the Institute of Astronomy of the RAS (INASAN). The second payload is responsible for observing the Sun in various wavelengths, from X-ray to IR, as well as for measuring the magnetic field and detecting particles. This payload has been under development at the Space Research Institute of the RAS. The main practical goal of the SODA payload is to provide a warning for "almost all" hazardous day sky asteroids. Its scientific goals are to validate existing models of small bodies in the Solar System and to investigate a correlation between close flybys of asteroids near the Earth and meteor shower events. The SODA scientific payload consists of four 30 cm aperture wide-field telescopes that operate in visible light. Asteroid detection will be carried out using a "barrier" survey technique. Dangerous objects will be tracked until they approach Earth. For asteroids on a collision orbit, SODA provides a 10-hour warning time (on average) before impact, along with a prediction of the asteroid's atmospheric entry point with an accuracy of 10-200 km. The accuracy of asteroid tracking from SEL1, and therefore the accuracy of predicting the impact region, could be significantly improved by using a triangulation tracking mode, which can be provided by two spacecraft operating simultaneously. We believe that international cooperation, both in space and on the ground, is the most effective and realistic way to build an efficient warning system against 10-50 m impactors.

ABSTRACT. Gravitational-wave observations allow us to determine source distances without external calibration. However, large localization errors limit their cosmological utility, since redshift information cannot be obtained from gravitational waves alone. Multi-messenger events, such as GW170817, enable host-galaxy identification, but such cases remain rare. The Hubble constant inferred from GW170817 is consistent with other measurements, albeit with large uncertainties. To reduce statistical errors, a much larger sample of GW sources with identified host galaxies is required. Observations in the mid-frequency band around 0.1 Hz can substantially improve both sky localization and distance measurements. Several proposed space-based detector concepts operating in this band could localize sources within volumes smaller than those occupied by individual galaxies, enabling unique host-galaxy identification. With detectors of moderate sensitivity, the typical redshift horizon could be extended to ~0.1 for binary neutron star mergers and ~0.3 for neutron star–black hole mergers. Such capabilities would allow us to constrain key cosmological parameters with a precision comparable to that achieved by measurements of the Cosmic Microwave Background (CMB).

ABSTRACT. Influence of the thermoelectric effects on the coupled magnetothermal evolution of magnetic and electric fields in neutron stars is considered in two models. In the first one we analyze a conducting cylinder with a uniform magnetic field along its axis and radial temperature gradient at the stationary state. At large temperature gradients the azimuthal Hall electrical current creates an axial magnetic field whose strength may be comparable with the original one. It is shown that the magnetic field, generated by the azimuthal Hall current, leads to the decrease of a magnetic field originated by external sources, and this suppression increases with an increase of the electromotive force, connected with thermodiffusion. In the second one we describe a situation that can occur in the neutron star after its birth. Some layers of the neutron star may become electrically charged, and at presence of accretion and outer electron supply the neutron star may acquire a negative electrical charge. We consider a model of a conductive cylinder with a radial temperature gradient that creates an electric field growing over the time in the surrounding vacuum. The generation of an electric field also occurs in the presence of a magnetic field along the axis of the cylinder. Four models are considered with different conditions for the supply of electrons from a central source and the ability to either capture electrons inside the cylinder, or to allow them to leave freely through the outer boundary.

ABSTRACT. Since the first detection of gravitational waves from a binary neutron star inspiral in 2017, the LIGO–Virgo–KAGRA detectors have continued searching for gravitational wave events with ever-improving sensitivity, leading to an expanding catalog of detections. Given its unique orientation in the detector network, KAGRA plays a crucial role in the sky localization of gravitational wave events. However, KAGRA's ability to locate gravitational wave sources remains a challenge due to limited sensitivity, which makes electromagnetic observation of binary neutron star mergers difficult.

In this study, we aim to assess the ability of KAGRA to locate gravitational wave sources at different, potential target sensitivities. In particular, we assess the relative improvements to sky localization with and without KAGRA when compared with a combination of LIGO and Virgo detectors at their current sensitivities. Based on these results, we identify at which sensitivities KAGRA will be able to significantly contribute to the binary neutron star multimessenger science. These findings highlight the importance of KAGRA’s development to enabling precise multi-messenger observations of future binary neutron star mergers.

ABSTRACT. The results of MHD simulations of supersonic astrophysical and laboratory jets in an external poloidal magnetic field taking into account the rotation of the matter, are presented. The ejected matter is collimated by the magnetic field, the degree of collimation and the flow structure depend on the relation between of the magnetic field induction and the angular velocity of the matter. For a strong magnetic field and moderate rotation, a barrel-shaped structure of an elongated shape is formed, which leaves behind a stable outflow. Inside the jet ejection, a barrel-shaped a periodic shock-wave structure is observed. For a moderate magnetic field and rapid rotation, the ejected matter at first significantly expands, but then gradually collimates into a jet due to the appearance of a toroidal magnetic field . A cocoon-shaped structure is formed. It spreads to the boundary of the computational domain. Inside the jet cocoon, a cavity with a low density of matter, quasi-stationary in time near is formed. In all cases, the rotation of the matter in the jet is transmitted to neighboring regions, which ultimately leads to the generation of magneto-torsional oscillations associated with the appearance of a toroidal component of the field. The toroidal field arises during the twisting of the poloidal magnetic field due to the dependence of the jet matter angular velocity on the radial and axial coordinates. The toroidal field also participates in the collimation of the jet.

ABSTRACT. Polarized galactic dust and synchrotron emission encode the coupled dynamics of turbulence, magnetic fields, chemical evolution, and cosmic rays in the interstellar medium (ISM). While traditional models attribute small-scale polarization fluctuations primarily to magnetized turbulence driven by supernovae and galactic shear, they typically neglect the dynamical role of cosmic rays and molecule-driven cooling. In this talk, I will present the Cosmic Ray–Interstellar Medium (CRISM) Model, which augments multiphase MHD turbulence with anisotropic cosmic-ray transport and non-equilibrium chemistry. In CRISM, radiative cooling through CO and CN molecular lines triggers thermal instability that converts Alfvénic into compressive modes on ∼1 pc scales. These compressive structures enable first-order Fermi acceleration of cosmic rays in the 10⁴–10⁵ GeV range, providing a potential explanation for spectral features reported by LHAASO and GRAPES-3. High-resolution 3D simulations based on this model reproduce the nearly incompressible polarization patterns observed by Planck, and we show that this behavior emerges from a self-regulating feedback loop: cosmic-ray pressure and chemical cooling damp compressive turbulence, sustain predominantly solenoidal motions, and imprint distinctive signatures on dust and synchrotron polarization. This links microphysical processes in the ISM to observable polarization statistics, with implications for cosmic-ray transport, star formation, and the characterization of foregrounds in next-generation CMB B-mode searches.

ABSTRACT. The discrepancy between mass and light distribution in galaxies points to the existence of dark matter. While the standard ΛCDM model successfully explains the universe's large-scale structure, it faces challenges on smaller scales. This leads to the need for alternative dark matter models beyond Cold Dark Matter (CDM). Self-Interacting Dark Matter (SIDM) is a promising option to address these challenges by modifying the structure of galaxy halos. SIDM has been tested on galaxy and cluster scales, but studies on the galaxy group scale remain limited. This research aims to determine the SIDM collision cross-section per unit mass (σ/m) at the galaxy group scale and to examine the relationship between σ/m and collision velocity. Using strong gravitational lensing data from recent surveys, this study is expected to fill the knowledge gap at the galaxy group scale, improve our understanding of SIDM, and provide insights into the evolution of the universe's structure.

ABSTRACT. Galaxy sizes, shapes and colours are an incomplete and inefficient basis for testing galaxy formation physics using information available in telescope images. Current computer vision models overcome these limitations. I will show how machine learning can be used to test the viability of galaxy formation models directly from images. I will discuss the successes and shortcomings of three prominent galaxy formation models (TNG, SIMBA, EAGLE) as compared to observed galaxies from the Subaru HSC program using deep contrastive models. Lastly, I will show that the information extracted from optical images is sufficient to reconstruct pertinent details of observed galaxy assembly histories. As new facilities like Xuntian, the SKA, and FAST probe the detailed structures of galaxies ever more sensitively, these simulation-based inference tools will serve as an increasingly complete and efficient basis for testing physics and inferring how observed galaxies formed.

ABSTRACT. Studying the faintest components of galaxy formation is essential for connecting high redshift observations to $\Lambda$CDM models. JWST is rapidly expanding the census of extremely faint galaxies in the early Universe, which makes it timely to calibrate how mergers and feedback imprint long lived signatures on galaxy structure in ways that can be tested with detailed dynamical modeling. The Andromeda galaxy provides an unusually rich laboratory because the stellar halo encodes a dynamical fossil record of minor mergers and interactions with dark substructure tied to the missing satellite problem, with observables accessible in six-dimensional phase space.

We present a compact, testable framework that links several major halo components, including the Andromeda Giant Southern Stream (AGSS), the Eastern Extent (EE), the North Eastern Shell (NES), the Western Shell (WS), the North Western Stream (NWS), and the faint pair Stream C and Stream D, and we highlight discriminants that directly probe the dark side of galaxy formation.

First, Yamaguchi et al., PASJ, 77, L36–L42 (2025) show that a single minor merger, with progenitor halo parameters within the $\Lambda$CDM allowed range, can simultaneously generate the AGSS, EE, NES, and WS. The NES and WS are robust outcomes, whereas the EE shifts northward for a shallower progenitor halo, which makes the EE a lever on the progenitor potential. The model also predicts a key three-dimensional separation: EE lies tens of kiloparsecs closer than Stream C despite close alignment on the sky. A sharp spectroscopic prediction follows, namely a positive-velocity AGSS component with line-of-sight velocities above the systemic value, coexisting with the observed negative-velocity stream and contributing directly to the EE.

Second, Kirihara, Miki, Mori, MNRAS, 469, 3390–3395 (2017) constrain the NWS progenitor orbit and find two orbital branches, where distance measurements provide the decisive discriminator. Komiyama et al., ApJ, 853, 29 (2018) report a clear density gap along the NWS, motivating an interaction with a dark satellite and providing a direct handle on the hidden subhalo population.

Finally, Kaneda et al. (to be submitted) show that an oblique encounter with a starless dark satellite can split one stream into two long lived, nearly parallel flows, which provides a new observable signature of the hidden subhalos that drive the missing satellite problem. Together, these models provide quantitative, falsifiable tests that link merger driven assembly, stream morphology, and dark perturber signatures, strengthening the bridge between JWST era high redshift galaxies and the physics of galaxy formation in $\Lambda$CDM.

ABSTRACT. Void galaxies reside in the most under-dense environments of the Universe, where galaxy interactions are rare and secular processes dominate their evolution. These systems, therefore, provide ideal laboratories to study the slow buildup of stellar mass through star formation in relative isolation. While the stellar properties of void galaxies have been studied extensively, their cold gas reservoirs - both molecular (H2) and atomic (HI) - remain poorly explored. The Bootes Void is the largest cosmic void in the universe, and we mapped, for the first time, the distribution of molecular gas in a void galaxy, CG 910, located within the Bootes Void. We utilised the CO(1–0) observations from the Combined Array for Research in Millimetre Astronomy (CARMA) and combined the molecular gas with the atomic hydrogen (HI) observations from the Robert C. Byrd Green Bank Telescope (GBT) to study the star formation in the massive-disk galaxy. In this talk, I will discuss the molecular gas distribution and velocity field, along with the atomic gas properties, and compare the star formation properties with those of typical disk galaxies. In addition to molecular gas, the environment of a galaxy can also significantly influence its evolution. Therefore, this galaxy with only one nearest neighbour represents a simpler system for understanding the effects of the local and large-scale environments. I will quantitatively highlight the tidal strength parameter using the SDSS-Galaxy Environment for MaNGA (GEMA) catalogues. Recent studies suggest that the star-formation properties of their void galaxy sample differ little from those of normal star-forming galaxies, except at the high-mass end. Therefore, the case study of this galaxy with higher stellar mass is particularly important in understanding the origin and evolution of massive galaxies in void environments.

ABSTRACT. At the end of the Dark Ages, when the first structures of the Universe were formed, radiation from these structures ionized the neutral hydrogen atom surrounding its environment. This crucial phase is known as cosmic re-ionization. It is the last phase transition undergone by the Universe, finishing around z~6. Today, various hypotheses exist concerning the main contributors to this process, such as Active Galactic Nuclei (AGN), star-forming galaxies, etc. I assess the contribution of the star-forming galaxies to cosmic reionization by studying the evolution of the luminosity function with redshift, estimating their star formation rate density as well as the escape fraction of Lyman alpha photon at different redshift ranges through the use of VLT/MUSE as well as gravitational lensing. For this purpose, the work assembles the largest sample of lensed Lyman-alpha emitters: 600 faint galaxies identified by the Lyman-α emission line (LAEs) to date (at redshifts between 2.9 and 6.7). The best-fit results of the Schechter function at different redshift ranges allow us to determine the luminosity density and convert it to the star formation rate density. These results, compared with those of the critical value for the star formation density, suggest that galaxies selected by their Lyα emission could be responsible for reionization assuming a Lyα photon escape fraction of 8%, with a typical clumping factor of ∼ 3. On the other hand, when assessing the escape fraction of Lyman alpha photons from star-forming galaxies we found that the LAE population could have provided all the photons necessary for reionisation at z=6 using well-motivated assumptions about the ionising photon efficiency and the escape of ionising photons from these galaxies.

ABSTRACT. --Context and Motivation-- Ultra-diffuse galaxies (UDGs) present a puzzling class of low surface brightness objects with extended sizes yet stellar masses comparable to dwarf galaxies. While observational studies reveal that UDGs populate diverse environments from the field to galaxy clusters, their formation mechanisms remain actively debated. Recent observational work has identified two distinct UDG populations: gas-rich, blue, GC-poor systems in lower-density environments, and older, red, GC-rich systems in denser environments. This diversity suggests multiple formation pathways. Scientific Questions Can gas-rich dwarf–dwarf mergers transform GC-poor "puffy dwarf" UDGs into GC-rich systems? Can such mergers reproduce the observed properties of globular clusters and explain the presence of extended structures alongside high cluster formation efficiency? These questions motivate our investigation into mergers as a viable UDG formation channel. --Methodology-- We present high-resolution hydrodynamic simulations of 1:1 and 1:2 gas-rich dwarf galaxy mergers, complemented by an isolated control run. Using the ASURA N-body/SPH code with particle-level resolution of 2 × 10³ M☉, we achieve sufficient resolution to identify bound stellar overdensities as globular cluster candidates (GCCs). The progenitor galaxies are initialized as gas-rich UDGs themselves, with realistic metallicities and rotation profiles set on bound two-body orbits. --Key Results-- The post-merger remnants satisfy UDG criteria with stellar half-mass radii of 1.9–2.7 kpc and dispersion-supported kinematics. Merger-driven starbursts during pericentric passages produce highly clustered star formation, with >60% of newly formed stars residing in bound clusters. By the final snapshots, the 1:1 and 1:2 merger remnants host 17 and 31 globular cluster candidates, respectively, with total masses of 4.1 × 10⁶ and 8.3 × 10⁶ M☉. The structural and dynamical properties of simulated GCCs—including size, velocity dispersion, density, and their mutual scaling relations—closely match observations of Milky Way globular clusters and young massive clusters. We identify strong correlations: rotation velocity increases with cluster mass (Pearson r = 0.83), younger clusters rotate faster, and metallicity dispersions scale with mass, consistent with self-enrichment in deeper potential wells. Mean cluster metallicities are [Fe/H] ∼ −1.3, matching local dwarf galaxy trends. Notably, one merger remnant develops a nuclear star cluster with 11% of the galaxy's total stellar mass, demonstrating how mergers can produce nucleated UDGs. The isolated control galaxy forms no globular clusters despite comparable gas content, indicating that interactions are essential for cluster formation. --Implications-- Our results establish gas-rich mergers as a viable formation pathway for transforming GC-poor UDGs into GC-rich systems while maintaining faintness. The simulations predict testable correlations between cluster rotation, metallicity dispersion, and mass. We also clarify the distinction between merger and tidal-interaction channels in producing UDGs with rich cluster populations, with observational implications for systems like UGC 9050-Dw1 and GAMA 526784.

ABSTRACT. TBA

ABSTRACT. I will present an overview of the first data release of products from the Middle Ages Galaxy Properties with Integral Field Spectroscopy (MAGPI) survey, a Large Program that used adaptive optics (AO) and the Multi-Unit Spectroscopic Explorer (MUSE) on the European Southern Observatory Very Large Telescope. MAGPI is designed to study the physical drivers of galaxy transformation at a lookback time of 3–4 Gyr (0.26<z<0.42), during which the dynamical, morphological, and chemical properties of galaxies are predicted to evolve significantly. At this epoch MUSE provides integral field spectroscopic (IFS) coverage from 3500-7000Å and can measure absorption features sensitive to stellar age (e.g., 4000Å break) and emission lines ([OII] to [SII]) sensitive to the interstellar medium. Despite having a primary focus at z∼0.3, there are thousands of additional galaxies serendipitously detected in the MUSE field-of-view that can be studied and are included as part of this release. This data release includes emission line maps and aperture-based emission line measurements based on the GIST software for all 56 MAGPI fields and includes 2,607 galaxies with secure spectroscopic redshifts at 0.05<zspec<1.50, where 701 (27%) of these are at 0.26<zspec<0.42. Dust attenuation represents a source of major uncertainty on derived properties of galaxies and developing accurate theories of galaxy evolution. Using the MAGPI IFS data, we examine the role of spectroscopic aperture size on the relationship between the Balmer decrement (Flux(Ha)/Flux(Hb); a common proxy for dust attenuation) and total stellar mass, which is a method for making dust attenuation corrections. Several studies have suggested this relationship may be redshift invariant, however the samples compared often have different spectroscopic apertures that cover only a fraction of the total galaxy (e.g., fiber or slit size). Our results indicate that the aperture size has a significant impact on this relationship, due to radial gradients in the Balmer decrements of galaxies, and that the Balmer decrement-total stellar mass relation does vary with redshift when comparing surveys with spectroscopic coverage of the entire extent of galaxies (e.g., IFS or slitless spectroscopy).

ABSTRACT. The Transneptunian Automated Occultation Survey (TAOS II) aims to measure the size distribution of small (D ~ 1 km) Trans-Neptunian Objects. Such objects are very faint (r' > 40) and are undetectable by even the largest telescopes. TAOS II is a blind survey, designed to simultaneously monitor many stars (typically 5000) at a 20 Hz cadence in order to detect serendipitous occultation events. TAOS II is operating three 1.3 m telescopes at San Pedro Martir Observatory in Baja California, Mexico. Each telescope is equipped with a custom 88 Mpix CMOS camera, capable of reading out up to 12,000 sub-frames around our target stars at a cadence of 20 Hz. In addition, the high cadence lightcurves can be used for the studies of variable stars, exoplanets and transient events. TAOS II began survey operations in 2025 September, and has already collected over 60,000 star-hours of high-cadence photometry. In this presentation, the preliminary results and performance of the TAOS II system will be discussed.

ABSTRACT. I will present cosmological constraints using the abundance of weak-lensing shear-selected galaxy clusters selected in the Hyper Suprime-Cam (HSC) Subaru Strategic Program. The clusters are selected on the mass maps constructed using the latest three-year (Y3) weak-lensing data with an area of ~ 500 deg2, resulting in a sample size of 129 clusters with a high signal-to-noise ratio \nu of \nu >= 4.7. Owing to the deep, wide-field, and uniform imaging of the HSC survey, this is by far the largest sample of shear-selected clusters, in which the selection solely depends on gravity and is free from any assumptions about the dynamical state. We obtain the fully marginalized constraint on \hat{S}_8 \equiv \sigma_8 \left(\Omega_{m}/0.3\right)^{0.25} = 0.835^{+0.041}_{-0.044} (corresponding to a ~5% constraint) in a flat LCDM model. This work realizes a cosmological probe utilizing weak-lensing shear-selected clusters and paves the way forward in the upcoming LSST era. In the second part of the talk, I will share the latest development of the shear-selected cluster sample in the HSC survey.

ABSTRACT. Thermonuclear supernovae (SNe) exhibit a much broader diversity than that traditionally described by normal SNe Ia. Among them, the 2003fg-like and 2002es-like subclasses represent two extreme populations, characterized by their overluminous and subluminous nature, respectively. Despite these differences, recent studies have revealed intriguing similarities between the two, particularly their bright ultraviolet emission at early times, leading to suggestions that they may share a common origin. In this work, we investigate this hypothesis using host-galaxy environments as an independent probe of their progenitor properties. We compile the largest sample of 2003fg-like and 2002es-like SNe to date, with homogeneous UV-to-IR host-galaxy photometry, and derive host-galaxy properties through multi-band spectral energy distribution fitting. We find clear environmental differences between the two subclasses, indicating that they are unlikely to originate from the same progenitor systems.

ABSTRACT. Precision cosmology has entered an era where tensions between datasets demand robust methods for model comparison and tension quantification. In this talk, I introduce unimpeded [2511.04661, 2511.05470], an open-source, pip-installable Python library that provides an archive of nested sampling chains and posterior samples across 13 cosmological surveys and 8 models. unimpeded turns weeks of supercomputer time into seconds on a laptop, enabling systematic Bayesian model comparison and tension quantification. As a case study, I will present a fully Bayesian reanalysis of the DESI DR2 BAO data in combination with Planck CMB measurements, multiple supernova catalogues (Pantheon+, Union3, DES-SN5YR, DES-Dovekie), and DES-Y1 weak lensing [2511.10631, 2603.05472]. The DESI Collaboration reported a significant frequentist preference for dynamical dark energy over ΛCDM. I will show that using the recently recalibrated DES-Dovekie supernova calibration, the three-probe combination shows no evidence for dynamical dark energy model. I will explain how the systematic discrepancy between the Bayesian and frequentist conclusions arises from the Jeffreys–Lindley paradox. I will show how our tension metrics identified a significant conflict between DESI DR2 and the original DES-SN5YR supernova sample within ΛCDM, and how this tension is absorbed when switching to dynamical dark energy models, producing an apparent preference for new physics. These findings highlight the value of Bayesian tension quantification as a safeguard against interpreting dataset-level systematics as evidence for new physics, while showing that such analyses can be carried out efficiently with the unimpeded package.

ABSTRACT. Emerging evidence for closer secondary or tertiary bodies offers new insight into the long-standing problem of the apparent coexistence of nearly spherical shells around asymptotic giant branch (AGB) stars and highly bipolar outflows that likely emerge during the transition to the post-AGB phase.

Recent high-resolution, high-sensitivity ALMA observations have revealed a growing number of AGB stars exhibiting multiple shell and spiral-like structures, broadly consistent with dynamical influences from companions and extending into shorter orbital-period regimes. This observational frontier raises the possibility that even lower-mass companions—possibly including giant planets—may leave detectable imprints.

Beyond these large-scale patterns, ALMA has uncovered rich fine substructures in the inner circumstellar envelopes, pointing to more complex mass-loss dynamics than previously assumed. Recent theoretical studies of hierarchical triple star systems suggest that even seemingly irregular substructures may reflect underlying dynamical regularities, naturally arising from multi-body interactions. Hydrodynamic simulations of accretion disk formation around companions further indicate significantly enhanced mass accretion rates, including strong periodic modulation in eccentric systems. Together, these results highlight the potentially significant dynamical role of detached companions on circumstellar evolution during the late stages of stellar life.

ABSTRACT. W 43A is a prototypical "water fountain", which hosts a highly-collimated molecular jet (>100 km/s) from a system of a dying star and is traced by water maser emission. Here we present our latest exploration for the central stellar system of W 43A through our ALMA observations. The maps of 1.3 mm continuum and SiO v=1 J=5->4 maser emission suggest that the size of the central stellar system, which may be in a common-envelope evolution of a binary, should be within 20 au. The maps of CO J=2->1 and SiO v=0 J=5->4 emission imply that the collimated jet should have precession so as to eject gas blobs alternating their red-shifted and blue-shifted components in every 5--7 years. These information will shed light on the mechanism of launching a jet from a dying star and the evolution of a binary system, which is performing massive stellar mass loss (in an order of 10^-3 M_sun/yr), forming a planetary nebula (within 100--1000 yr) with a complicated morphology, and likely going to a type-Ia supernova explosion.

ABSTRACT. Determining oxygen abundances in very metal-poor (VMP) stars ([Fe/H] = –4.0 to –1.0) remains challenging, particularly at lower metallicities, due to the weakness and telluric contamination of the [O I] forbidden line—the most reliable oxygen indicator in the optical range. Oxygen, like carbon, is typically overabundant in VMP stars ([O/Fe] > 0.5); however, to identify and study stars with potentially lower oxygen abundances, alternative and reliable oxygen tracers are required. In this study, we investigate the reliability of near-infrared OH vibration-rotation lines as oxygen abundance indicators in a metallicity regime where the [O I] line is unusable. Using high-resolution Subaru/IRD spectra (R ∼ 70,000), covering numerous first overtone OH lines in the H-band (1.5–1.7 μm), we determined oxygen abundances for 35 E/VMP stars (34 red giants and 1 dwarf). To ensure consistency, we recalibrated the effective temperature, surface gravity, and iron abundance for all stars prior to determining oxygen abundances. Oxygen abundances were derived using 1D LTE models for all stars. For 21 of these stars, we also derived oxygen abundances from the [O I] 6300 Å line using archival Subaru/HDS and VLT/UVES spectra. Additionally, we provided new [O I] 3D/LTE correction grids covering red giant branch stars. This allows us to directly assess the consistency between OH and [O I] indicators. Our results show that OH abundances are extremely sensitive to the derived temperature, but with carefully calibrated temperatures, we achieve abundance differences of <0.2 dex for most of the stars. This study provides new observational constraints on oxygen abundance measurements in the VMP regime and offers further insights into nucleosynthesis in massive stars, core-collapse supernovae, and the chemical evolution of the early Galaxy.

ABSTRACT. We present the first comprehensive astrochemical study of how FU Orionis-type luminosity outbursts affect water ice deuteration in protoplanetary disks. This work addresses ALMA observations of the FUor V883 Ori, revealing two key anomalies inconsistent with its current luminosity (~400 L⊙): a high gas-phase HDO/H₂O ratio and a water snowline at ~80 au from the star.

Using the ANDES astrochemical code, we modeled the chemical evolution of a V883 Ori-like disk under outbursts of varying amplitudes (400–10,000 L⊙). Our models include a full deuterium chemistry network, a 2D disk structure, and an envelope, examining how the radial HDO/H₂O profile responds to single and consecutive outbursts, and its dependence on the star's pre-outburst luminosity (ages 0.1 and 0.5 Myr).

Key findings:

Outburst Amplitude is Critical: Models with a 400 L⊙ outburst fail to reproduce the observed HDO/H₂O profile and place the snowline at only ~20-30 au. In contrast, models with brighter outbursts (2000 and 10,000 L⊙) successfully replicate the elevated HDO/H₂O ratio at 40–140 au and shift the snowline to 60–100 au, matching observations.

A Chemical Fossil Record: The gas-phase HDO/H₂O ratio during an outburst is set by the composition of pre-existing water ice. The high deuteration in V883 Ori is thus a chemical fingerprint of pristine, cold-formed ice sublimated by a past cataclysmic heating event.

Primary Scenario for V883 Ori: The ALMA data are best matched by a model with a past super-bright outburst (~10,000 L⊙). This signature persists even with a subsequent weaker outburst (~400 L⊙), explaining the system's current low luminosity and chemically primitive disk.

Thermal Structure Sensitivity: The observed snowline and HDO/H₂O profile could also be reconciled with a 400 L⊙ outburst if an alternative, steeper midplane temperature profile (T∝R^(-3/7)) is adopted. This underscores the critical role of accurately determining the disk's thermal structure.

Our study shows that water deuteration in protoplanetary disks acts as a sensitive chemical archive of past episodic accretion. For V883 Ori, the data strongly favor a history of a giant accretion burst. This result robustly supports the "inheritance" scenario, where water ice with a high deuterium fraction, formed in the cold interstellar medium, survives transport into the disk with minimal reprocessing. These findings forge a crucial link between the dynamic accretion history of young stars and the final chemical composition of planetary-building materials, directly impacting our understanding of the origin of water in planetary systems.

ABSTRACT. Dark clouds from the Clemens and Barvainis (CB) catalogue represent compact, dense regions of the interstellar medium that are often observed as isolated dark patches against the bright stellar background. From a total of 248 CB clouds, we identify 48 clouds that show isolated, well-defined shapes. For these selected clouds, the distance of each cloud is available from the literature, while the distances of stars along the line of sight are obtained from the Gaia catalogue, and the corresponding extinction data are taken from the 2MASS catalogue. Combining these datasets, we investigate the variation of visual extinction (A_V ) across the cloud’s radial extent. We observe a clear trend in which visual extinction increases from the cloud’s diffuse outer periphery toward its denser central region. This increasing extinction can be fitted using mathematical models dependent on radial distance and other physical parameters.

ABSTRACT. The universe is a dynamic place, despite its apparent stillness. Every second, a star explodes into a supernova somewhere in the universe, dispersing the nucleosynthetic products of its progenitor star into the interstellar medium. Supernovae from massive stars produce the first heavy elements, molecules, and dust in the nascent universe, setting the initial conditions for subsequent stellar and planetary formation. Despite their crucial roles in almost every field of astrophysics, several aspects of massive stellar evolution and their explosive deaths remain poorly understood. Most importantly, the multitude of all-sky surveys in the past decades unleashed a stream of new objects competing for our limiting follow-up observation facilities. I will present the current and upcoming infrastructure at the National Astronomical Research Institute of Thailand (NARIT) that allows our astronomers to search, classify, and follow up these stellar explosions. I will discuss the Thai Robotic Telescopes, a network of 0.7-m telescopes we are using to find new supernovae and other transients in the nearby universe. In addition, we are part of the Cryoscope pathfinder that will begin surveying the near-infrared sky above Antarctica in 2027. I will discuss the follow-up observation facilities at the 2.4-m Thai National Telescope, including a high speed imaging camera and a low-resolution spectrometer. Finally, I will discuss the Dual-beam Automatic Rapid Transient Spectrograph (DARTS), being constructed at NARIT in collaboration with the University of California Observatories to be installed at Lick Observatory. Anticipating the first light in 2027, this robotic spectrograph will autonomously obtain spectra to quickly classify new transients, follow rapidly evolving events, and study supernovae in the first moments after the explosion.

ABSTRACT. ULTIMATE-Subaru is the next-generation facility instrument program of the Subaru Telescope which will extend the existing Subaru’s wide-field survey capability to the near-infrared wavelength. The ULTIMATE-Subaru includes Ground-Layer Adaptive Optics (GLAO) and wide-field near-infrared instruments, aiming to provide ∼0.2 arcsec image size at K band (2.2 micron) over 20 arcmin diameter field of view at the Cassegrain focus. The planned first light instrument is a Wide-Field Imager (WFI), which covers a 14 × 14 square arcmin field of view from 0.9 to 2.5 micron in wavelength. With an improved image quality, sensitivity, and a unique set of narrow- and medium-band filters, the key science goals of ULTIMATE-Subaru is to reveal the birth, growth, and death of galaxies across cosmic time and environment. In addition, deep and sharp near-infrared imaging capability of ULTIMATE-Subaru will also provide a powerful tool for any astronomical studies targeting dense and/or obscured environment (e.g. Galactic Center, Galactic Plane, or Star forming regions). The development of the ULTIMATE-Subaru instruments are being conducted in collaboration with the Subaru Telescope, Advanced Technology Center in the National Astronomical Observatory of Japan, Australian National University, the Academia Sinica Institute of Astronomy and Astrophysics, Tohoku University, and the University of Tokyo. The GLAO and WFI systems are currently in the end of the final design phase, aiming to complete the key-component prototyping and design, and to start production in early 2026. In this presentation, an overview of the ULTIMATE-SUBARU instruments, their current status, and future prospects will be presented. We also provide an overview of the key science goals to be enabled by novel survey observations using the ULTIMATE-Subaru.

ABSTRACT. Corrections for the absorption of light by interstellar dust (referred to as dust extinction) represent one of the largest sources of uncertainty for deriving properties of stars and galaxies in astronomical studies, particularly those that rely on ultraviolet (UV) wavelengths where dust extinction is strongest. The origin of the 2175Å absorption feature (the most prominent UV dust extinction feature) is still a mystery and this lack of understanding directly limits the accuracy to which dust extinction corrections can currently be made. The reason for this limited knowledge is due to the sparsity of UV extinction measurement to date, with only a few hundred sightlines being measured from all past/current facilities. Recent advancements in UV instrumentation and technologies have paved the way for the development of high-throughput UV instruments in compact form factors. The Ultraviolet Extinction Sky Survey (UVESS) is an UV spectroscopic SmallSat mission concept led by the Australian National University, in collaboration with the Indian Institute for Astrophysics and the International Space Centre (UWA). We are also seeking further engagement with the wider space- and scientific-communities. UVESS would map the variability in dust extinction curves and 2175Å dust absorption feature by acquiring UV spectroscopy (1500-3000Å; R~200) for thousands of sightlines across most of the sky, probing the interstellar medium in the Milky Way and Local Group galaxies. These characterisations will offer valuable insights into the composition, size distribution, and processing of interstellar dust grains. Understanding these factors are critical to developing more accurate prescriptions for dust extinction corrections in astronomical observations. I will outline the UVESS mission concept, science goals, and status.

ABSTRACT. As of 2026, the Timau National Observatory (OBNAS), situated at an altitude of 1,300 meters on Mount Timau, East Nusa Tenggara, has transitioned from its primary construction phase to the initial commissioning phase. The facility addresses the critical need for a pristine, low-light-pollution site in the equatorial southern hemisphere, offsetting the urban encroachment affecting the historic Bosscha Observatory. The centrepiece of the facility, a 3.8-meter segmented-mirror optical telescope (a technological twin to Japan's Seimei Telescope), successfully achieved its engineering first light in late 2025 following the alignment of its 18 hexagonal mirror segments. Current operational status indicates that the first-generation three-band optical imager (TRIOPTIKA) is ready for a more on-site testing, while the near-infrared camera (NIRKA) is undergoing final integration for 2026 deployment. Recent site characterization data confirms a median seeing of 0.8 to 1.2 arcseconds and an average of 66% usable nights annually, validating the site’s strategic value for time-domain astronomy and space situational awareness. This study summarizes the current technical benchmarks, the integration of the local Dark Sky Park initiative, and the observatory's role in the burgeoning global network of equatorial astronomical research.

ABSTRACT. The Chinese Space Station Telescope (CSST) is a major space-based astronomical observation facility planned and constructed under the China Manned Space Program. The optical telescope assembly (OTA) features a 2-meter aperture and an off-axis three-mirror anastigmatic (TMA) design, in which the tertiary mirror employs a freeform surface. This configuration provides an excellent combination of wide field of view and high image quality, and it is further equipped with on-orbit optical alignment capabilities. The science instruments include the Survey Camera (SC), the Multichannel Imager (MCI), the Integral Field Spectrograph (IFS), the Cool Planet Imaging Coronagraph (CPI-C), and the high-sensitivity Terahertz Spectrometer (TS). While its core mission focuses on large-scale multiband imaging and slitless spectroscopic survey observations, CSST is also capable of performing high-precision, detailed observations of selected astronomical targets.

In 2025, the development team carried out a phased integrated testing campaign for CSST over more than two months at the largest thermal vacuum chamber in Asia, located at the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences. The compliance of CSST’s engineering specifications and its scientific performance were systematically verified and tested. Test results show that after the integration of the OTA with the scientific instruments, all key performance indicators met the design requirements, especially core parameters such as imaging resolution, detection sensitivity, and spectral resolution. These tests laid a solid foundation for the final integration and testing of the flight model, as well as for the achievement of its scientific goals after launch.

ABSTRACT. Solar magnetic fields and related solar magnetic activities dominate the heliospheric environments from the near-Earth space, to the interplanetary space, and up to the interstellar boundary. The polar magnetic fields of the Sun and its dynamic processes are especially vital in the aspects of manifesting the internal dynamo of the Sun, and shaping magnetic fields in the heliosphere. But so far, high quality observations of solar polar region is quite limited, especially the accurate polarization and Doppler imaging. The Chinese Solar Polar-orbit Observatory (SPO) Mission has been designed to directly image the solar polar regions in an unprecedented way by traveling in a large solar inclination angle (larger than 80 degree) and a small ellipticity. This mission has been officially approved in April 2025, and the expected launch time will be January 2029. In this presentation, we will give an overview of SPO.

ABSTRACT. The baryon cycles in and around galaxies control the processes of galaxy evolution and chemical enrichment. Observing the interstellar medium and circumgalactic medium is very crucial for solving the many puzzles of the baryon cycling processes. One important component of the gas is warm ionized phase which can be observed through optical spectroscopy. We are planning an all-sky, high spectral resolution, optical integral field spectroscopy survey using an array of cost-effective, fiber-fed spectrographs connected with small telescopes to map the warm ionized gas in the Milky Way and nearby galaxies. It is called the Affordable Multiple Aperture Spectroscopy Explorer (AMASE). The prototype instrument system is being developed right now. It includes three spectrographs connected with two primary science telescopes and three assistant telescopes. The spectrographs will cover two wavelength windows: 464-509nm and 625-685nm, with a spectral resolution of R~15,000. On the 14cm-aperture f/2.9 primary telescope, a 1519-fiber bundle enables integral field spectroscopy over a hexagonal field of view of 32 arcmin in long axis with an angular resolution of 26 arcsec. On the 0.8-aperture primary telescope, it will achieve a FoV of 3.9 arcmin and an angular resolution of 4.2 arcsec. I will describe the instrument and the prototype survey, AMASE-P, which will start within a year.

ABSTRACT. In 2019, the Event Horizon Telescope (EHT) Collaboration published the first-ever images of a black hole resolved at the scale of its event horizon. These images were based on observations collected over four days in the spring of 2017. More recently, the EHT has released images from additional observing campaigns conducted in 2018 and 2021. Across all epochs, the images are characterized by a bright ring surrounding a darker central region, interpreted as the shadow of the black hole. However, clear changes are observed from year to year, as expected from the turbulent nature of the accretion flow and its associated characteristic time. The polarization properties of the emission also evolve across epochs, with variations in both polarization fraction and magnetic field geometry. In this talk, I will present these images and their temporal evolution, and discuss the implications for the physical properties of the plasma surrounding the supermassive black hole at the center of M87. I will conclude with a brief overview of future observations and what we expect them to reveal.

ABSTRACT. We introduce TransFit, a new computational framework designed to efficiently model supernova light curves by numerically solving the time-dependent radiative diffusion equation. Motivated by the data deluge from next-generation surveys (e.g., LSST, CSST), TransFit overcomes the limitations of traditional semi-analytical models—such as the assumption of self-similarity and constant opacity—while maintaining a computational speed comparable to analytic prescriptions.

The framework supports arbitrary ejecta density profiles and diverse heating mechanisms, including radioactive decay and central engines (magnetars), making it applicable to a wide range of transients. We show that TransFit accurately models the transition from shock cooling to radioactively powered emission, a regime often poorly handled by simple analytic formulas. Through Markov Chain Monte Carlo (MCMC) fitting of observed events, including SN 1993J (Type IIb) and SN 2007gr (Type Ic), we demonstrate that TransFit can robustly infer physical parameters (ejecta mass, kinetic energy, and heating distribution). TransFit represents a scalable, physically rigorous tool for extracting detailed insights from the vast transient datasets anticipated in the coming decade.

ABSTRACT. We would like to share our recent discovery of a neutrino hotspot, with a post-trial significance of 3.2-sigma, at a position consistent with that of the pulsar wind nebula (PWN) G63.7+1.1. Pulsars or pulsar wind nebulae (PWNe) have long been suggested as possible neutrino emitters. For G63.7+1.1, a key feature related to its possible neutrino emission is that it is seen to be interacting with surrounding molecular materials. We examine the proton–proton interactions as the process for the neutrino production. The PWN (or the pulsar) can provide sufficient energy to power the required high-energy protons. This possibly first neutrino-emitting case in our Galaxy may reveal to us that PWNe are the significant Galactic high-energy neutrino sources.

ABSTRACT. Tidal disruption events (TDEs) are among the brightest transients in galactic nuclei, produced when stars are destroyed by supermassive black holes. It has been thought that strong relativistic effects drive efficient orbital energy dissipation and rapid disk formation in highly relativistic TDEs, where the stellar orbital pericenter is smaller than ~ 10 gravitational radii. Using a general relativistic hydrodynamics simulation of a strongly relativistic TDE around a 10**6 solar mass black hole, starting from the initial stellar approach and following the debris evolution past the peak mass return time (~ one month), we find instead that the overall evolution resemble that of weakly relativistic TDEs: the debris remains highly eccentric, with most of the returned mass residing near the orbital apocenter, and shocks, rather than accretion primarily power the event. Early strong shocks, driven by strong relativistic apsidal precession and pericenter nozzle compression, dissipate orbital energy efficiently, but last only about a week. Continuous stream self-intersections impart angular momentum to the incoming streams, gradually increasing the incoming debris' pericenter distances. Relativistic apsidal precession then weakens, diminishing the overall shock strength and the energy dissipation rate. Consequently, disk formation proceeds 10 - 20 times more slowly than conventionally assumed. These results, along with previous simulations of weakly relativistic TDEs, suggest that the disk formation process in TDEs may be intrinsically slow in relativistic cases as well as non-relativistic, and the resulting accretion flow remains highly eccentric during the peak in optical/UV luminosity.

ABSTRACT. In this work we simulate a series of core collapse supernova models of a massive rapidly rotating star with various precollapse magnetic field configurations, using global 2D axisymmetric magnetohydrodynamic model with a multiflavour neutrino leakage scheme. In the first part of this work, we report on the protoneutron star kick formation and explosion properties for equatorially asymmetric precollapse magnetic field configurations, such as compositions of magnetic multipoles, offset dipolar as well as dipolar + toroidal fields. Our simulations show, that protoneutron star kicks may be in order of 100-500 km/s at post-bounce times of order of 1 second. This may allow to explain the presence of bulk velocities of the neutron stars in the framework of magnetorotational supernova model. In the second part of this study, we analyze the effect of the magnetorotational instability (MRI) in the protoneutron star on the explosion properties and overall magnetic field evolution via the simulations on the fine grid, which resolves the MRI length scale.

ABSTRACT. Long gamma-ray bursts (LGRBs) are among the most luminous transients in the Universe, produced by highly collimated, relativistic jets. Their central engine is believed to be a rotating black hole formed during the collapse of rapidly rotating massive stars (collapsars). The Blandford–Znajek process remains one of the most promising mechanisms for jet launching, in which large-scale poloidal magnetic fields thread the event horizon of a rotating black hole and extract its rotational energy. However, differential rotation in the progenitor star primarily generates magnetic fields with a toroidal geometry, implying the need for a dynamo mechanism capable of converting toroidal fields into poloidal ones. We investigate whether such a dynamo can operate in collapsars by performing three-dimensional, general-relativistic magnetohydrodynamic simulations, using initial conditions informed by state-of-the-art stellar evolution models. We show that the magnetic field amplifies, develops a substantial coherent poloidal component, and is transported toward the black hole, enabling the launching of Poynting-flux–dominated outflows with a power of at least 10**51 erg/s, consistent with typical LGRB luminosities. Our results suggest a viable pathway for producing LGRB jets from realistic stellar progenitor models.

ABSTRACT. The eROSITA bubbles (eRObub) were discovered in 2020 in the first eROSITA All-Sky Survey (eRASS1), and are among the most extended structures in the X-ray sky. They appear to be emanating from the inner part of the Galaxy in projection. The eRObub encloses the gamma-ray Fermi bubbles, and the northern eRObub seems to be bounded by the north polar spur (NPS) in projection. The nature of the eRObub and their relation with the Fermi bubbles or the NPS remains elusive. In this talk, I will present our recent morphological and spectral analysis of the eRObub using the eRASS1 data in the western Galactic hemisphere.

Our morphological aims to infer the three-dimensional structure of the eRObub, under the assumption of a blast wave propagating from the Galactic centre into an idealised Galactic halo. Our geometrical model suggests that the horizontal size of both eRObub is well-constrained (semi-minor axis ~ 6 kpc), but their vertical extent is uncertain, as the observed X-ray emission is almost insensitive to the existence and location of a bubble cap. Additionally, a tilt (~30º) is needed to reproduce the projected image of the northern eRObub, whereas the southern bubble requires little tilt.

We examined the properties of the eRObub from their spectra. We found that the interior of the eRObub is dominated by two emission components with relatively uniform temperatures: a hotter component at kT=0.56^{+0.04}_{-0.02} keV and a colder one at kT=0.25 ± 0.03 keV, where the latter's emission measure is approximately four times higher. Our spectra suggest sub-solar abundances (Z=0.2±0.1 Z_sun), consistent with expectations for the Galactic halo, while we find no conclusive evidence for α-enhancement. One surprising finding is that the northern eRObub is surrounded by an apparent cool shell at kT~0.2 keV, likely in collisional ionisation equilibrium, which could be foreground. In contrast, the NPS exhibits higher abundances (Z>0.5 Z_sun), which, at face value, disfavours a common origin. We found no noticeable difference in X-ray emission in regions overlapping with the Fermi bubbles.

ABSTRACT. Recent JWST observations of proto‑cluster regions at z > 6 show that early galaxies do not grow steadily but instead cycle through brief, intense bursts of star formation phases. In overdense regions, the star‑forming main sequence is elevated by 0.3–0.5 dex, and more than half of galaxies exhibit instantaneous star‑formation rates over five times their 100 Myr averages, confirming that burstiness is both common and environmentally driven. These findings match theoretical and simulation results showing that high gas fractions and short dynamical times prevent feedback from reaching equilibrium, explaining the large scatter seen in the SFRHα‑to‑SFRUV ratios of high‑z galaxies. We have now extended this investigation to the nearby Universe using new MEGARA IFU spectroscopy of more than 15 HI‑rich galaxies selected from ALFALFA. By mapping spatially resolved kinematics and stellar populations, we can derive precise halo mass and spin parameters, proving that galaxies in high‑spin halos retain larger gas reservoirs and exhibit lower specific star‑formation rates. In contrast, low‑spin halos drive bursts of star formation and earlier quenching. Our data also confirm a correlation between halo spin and proximity to large‑scale filaments—galaxies closer to filaments have higher spins, implying that cosmic‑web tidal torques impart angular momentum. These results validate theoretical expectations that angular momentum and environment jointly regulate gas accretion and star‑formation efficiency. Nevertheless, many recent studies also suggested that while starting just to fall into overdensities, galaxies experience a slight spin-down. These could trigger the cyclical burst of star formation before the galaxies become relaxed. By bridging observations from cosmic dawn to the present day, we demonstrate that the innate environment—overdensity at high redshift and halo spin tied to filamentary structure at low redshift—plays a fundamental role in shaping galaxy star‑formation histories. These dual-regime observations provide a unified framework for understanding why some galaxies undergo rapid, burst‑driven growth while others sustain prolonged star‑forming lifetimes.

ABSTRACT. Galaxy evolution reflects a complex interplay of internal processes and environmental influences, yet many aspects remain poorly understood. In particular, the role of supermassive black holes (SMBHs) in regulating star formation is uncertain, due to challenges in measuring active SMBHs and tracing their long-term impact on host galaxies. In our study, accepted for publication in Nature Astronomy, we present a comprehensive analysis of ~60,000 nearby active SMBHs spanning a wide luminosity range, together with star formation rates, stellar masses, multiscale environments, and precise halo mass estimates for ~500,000 galaxies (active and inactive) from SDSS and GAMA surveys. This unified observational dataset enables a consistent comparison with three prominent cosmological simulations (SIMBA, TNG, and EAGLE) across multiple galaxy and SMBH properties. While simulations reproduce some broad trends, they exhibit major limitations: overproducing low-mass star-forming galaxies, misrepresenting quiescent population fractions, and over-quenching low-mass satellites in dense environments. Galaxies hosting optically selected active SMBHs predominantly occupy low-mass halos, broadly consistent with simulations, yet significant discrepancies remain in their number densities of stellar mass, star formation rates, stellar velocity dispersions, and accretion luminosities. These results highlight key shortcomings in current models of galaxy and SMBH co-evolution and provide an observational benchmark for improving future cosmological simulations.

ABSTRACT. Feedback from supernovae (SNe) and Active Galactic Nuclei (AGN) is known to govern galaxy formation and evolution. By injecting energy and momentum into the interstellar medium, these processes regulate the gas reservoir available for star formation. However, despite the coevolution of star formation and black hole growth, the specific mechanisms driving this feedback remain poorly constrained observationally. We investigate star-forming galaxies at the peak of cosmic star formation (0.6 < z < 2.6), using integral-field spectroscopy (IFS) from the K-band Multi Object Spectrograph (KMOS). We are able to isolate the gas with non-circular motion from the galaxy’s rotation. Among 396 galaxies with S/N >10 in their emission lines, we detect 110 sources (~28%) with robust outflow signatures via broad secondary components in their Hα and [N II] λλ6548,6584 emission lines. We find that the majority of the warm-ionised outflows have velocities below the escape velocity of their host galaxies, indicating that the gas remains gravitationally bound. We identified 24 AGN using multi-wavelength diagnostics (X-ray, mid-infrared, and radio). We examine the outflow scaling relations and compare them with predictions from analytical wind models. We also discuss the implications of outflows on the scatter in the Mass-Metallicity Relation (MZR) observed in star-forming galaxies at cosmic noon. Finally, we constrain the redshift evolution of the mass-loading factor for warm-ionised outflows, providing a key link between mass outflow rates and the cosmic star formation history.

ABSTRACT. JWST and ALMA are uncovering massive galaxies at z > 6 that formed rapidly, experienced bursty star-formation histories, and underwent early quenching episodes, sometimes only temporarily. I will present spectroscopic and morphological results for quiescent galaxies at z > 3–6, highlighting their chemical evolution, AGN fractions, and environments. Comparing these systems with reionization-era simulations such as THESAN reveals how mergers, overdensities, and feedback drove their rapid growth and shutdown, with implications for reionization, dust enrichment, and the emergence of galaxy diversity in the first billion years.

ABSTRACT. Deriving physical properties of high-redshift galaxies is essential to our understanding of the evolution of galaxies and how they interact with their environment in the early Universe. However, spectroscopic observations from the James Webb Space Telescope (JWST) remain scarce due to restricted survey areas, observing times, and sources’ diluted fluxes. These limitations introduce selection biases on the sample of distant galaxies. In this study, we propose a machine learning framework to predict key spectroscopic properties such as redshift, stellar mass, and star formation rate (SFR) directly from JWST photometric measurements. The approach utilizes the wealth of spectroscopic and photometric datasets of the Sloan Digital Sky Survey (SDSS) and the Principal Component Analysis (PCA). We decompose, reconstruct and transform SDSS spectroscopic data into a set of simulated z=3-10 galaxies’ spectra observable with JWST. Machine learning models, including Random Forest and Neural Networks, are trained on the simulated spectra and their projected NIR Cam photometries, then validated against available JWST observations from large surveys such as JADES. By bridging SDSS and JWST observational regimes, this study aims to improve the accuracy of photometric redshift estimation and provide a scalable method for inferring spectroscopic properties in the early Universe, enabling more efficient use of JWST photometric catalogs in future extragalactic studies.

ABSTRACT. We predict how jet outbursts from an active galactic nucleus (AGN) can induce and sustain non-thermal pressure (NTP) in their surrounding intracluster gas atmospheres. Our work is motivated by recent XRISM (X-ray Imaging and Spectroscopy Mission) observations, which have measured the amount of NTP in the hot central gas of galaxy clusters for varying AGN and jet activity. In our work, we predict how this AGN-induced NTP depends on both the environment of the cluster and the AGN’s duty cycle. Our work uses a semi-analytical approach: we simulate a statistical population of jet outbursts, evolve them in time as they propagate into the medium, and then determine the energy coupling, between the jet and the surrounding medium, as a function of halo radius based on the thermal state of the gas at each location. This allows us to infer the fraction of energy dissipated kinetically, driving turbulence and bulk motion in the gas, which we use to calculate the induced NTP. We find that the NTP is sustained at levels of typically a few percent of the thermal pressure of the gas, and that this fraction increases for higher duty cycles. This agrees with the recent findings made by XRISM, where higher NTP fractions have been observed in clusters hosting active jets. This work suggests that kinetic AGN feedback induces relatively small perturbations to their gaseous atmospheres, sustaining the gas in approximate hydrostatic equilibrium.

For a more detailed understanding of this kinetic feedback mechanism, we focus exclusively on the Perseus cluster - the X-ray brightest cluster in the sky - which XRISM has provided the most extensive observations for. Perseus is observed to host several pairs of jet-inflated cavities, suggesting high AGN activity in its recent history. We use the observed volumes of these cavities along with estimates for Perseus’ active age to set constraints on Perseus’ jet power, which we use to model outbursts with the dynamical model RAiSE (Radio AGNs in Semi-analytical Environments), fixing the cluster environment to follow that of Perseus’ observed gas density and temperature. This modelling allows us to place strong constraints on the energy injected into each of Perseus’ cavities. We model the long-term energetics by assuming that the under-dense lobe material left at the end of the outburst rises buoyantly into the surrounding intracluster medium; this allows energy to be dissipated out to larger halo radius. We then combine the resulting NTP predictions with a large-scale NTP profile generated by the cluster’s gravitational processes, such as mergers and shocks, which are known to increase in strength toward the virial radius. This outskirts model is determined by comparing Perseus’ observed gas fraction to an assumed universal profile, by assuming any differences are due to biases in the halo mass from non-thermal gas motion. The outcome of this work is the first complete NTP profile for the Perseus cluster, incorporating both AGN and gravitational feedback. Our hope is that this work will provide insights into Perseus’ energetic past.

ABSTRACT. Understanding how bulges and disks grow across cosmic time is key to uncovering the physical processes that shape galaxy evolution. We investigate the wavelength-dependent structural evolution of galaxies using a mass-complete sample of 44,000 star-forming galaxies (SFGs) and 34,000 quiescent galaxies (QGs) at z<0.85. By modelling bulges and disks separately in rest-frame UV (3000 Å) and optical (5000 Å) images from the CFHT CLAUDS and Subaru HSC-SSP surveys, we present the first systematic analysis of the size–mass relation (SMR) for individual galaxy components across two rest-frame wavelengths. For both SFGs and QGs, disks of Milky-Way mass-galaxies are significantly larger than their bulges, with the contrast being more pronounced in the UV. At fixed galaxy type, both bulges and disks are, on average, larger in SFGs than in QGs. Component sizes show strong wavelength dependence: disks are larger in the UV, while bulges are slightly more compact in the UV. We further find that bulge sizes grow more rapidly with mass than disk sizes, and that the growth rates differ across wavelengths. These results support a scenario in which bulge expansion dominates the structural evolution of SFGs, while the buildup of QGs is driven by recently quenched arrivals and minor mergers.

ABSTRACT. Galaxy size provides key insights into the physical processes driving galaxy formation and evolution. Using deep JWST/NIRCam and MIRI imaging from the PRIMER survey, we investigate the rest-frame optical size–stellar mass (Re–M*) relation of galaxies at 0.5 < z < 6.0. We find that star-forming galaxies (SFGs) exhibit a broken power-law relation at all redshifts, with a nearly constant pivot mass of Mp ≈ 10^10 M☉. Below Mp, the size–mass slope decreases from 0.22 at z = 1.25 to 0.15 at z = 5.0, while above Mp it flattens, decreasing from 0.15 at z = 1.25 to 0.02 by z = 5.0. This flattening highlights the prevalence of a population of compact, massive SFGs at high redshift, likely underrepresented in previous studies.

The size–mass relation of quiescent galaxies (QGs) also exhibits a broken power-law with a pivot mass of ≈ 10^10.6 M☉, suggesting different formation paths for low- and high-mass QGs. The bending in the size–mass relation of SFGs supports two distinct size growth modes. At M* < Mp, galaxy size growth is closely coupled to halo growth, while at M* > Mp, an increasing fraction of SFGs decouple from halo growth and become more compact, likely associated with rapid bulge (and black hole) growth in halos with Mh ≳ 10^12 M☉. These compact SFGs are promising progenitors of massive, compact QGs, suggesting that the compaction pathway, rather than major mergers of extended SFGs, dominates the formation of massive QGs at z ≳ 2.

ABSTRACT. Mephisto is a 1.6m Multi-channel photometric survey telescope developed at SWIFAR of YNU. The telescope has a 1.6-m primary mirror, a 2.25 sq.deg. usable field of view (FoV), and is equipped with three big mosaic CCD cameras totaling 1 billion pixels. Via innovative optical design, it combines a large light-collecting aperture, a large FoV, and multi-channel high-precision imaging, and can capture images in three bands simultaneously, providing ultra-high-precision photometry and color information of celestial objects and delivering 'true-color documentaries' of the dynamic universe. The photometric system consisting of six bands in total (uvgriz) covers the whole optical wavelength range from the near UV (320nm) to the far-red (1um), and is optimized for stellar atmospheric parameter determinations. The telescope was first installed at the Gaomeigu observatory in October 2022 with a pilot optical system covering 1/4 of the full FoV with two and, one year later, three single-sensor CCD cameras. The full optical system covering the whole FoV was successfully installed October, 2025, along with three mosaic CCD cameras. In this talk, I will outline the motivation, development, commissioning and early scientific results of the project, as well as its future plan.

ABSTRACT. Direct measurements of the local Hubble constant (H₀) using Type Ia supernovae (SNe Ia) yield values that are significantly higher than those inferred from the Cosmic Microwave Background (CMB), posing a notable challenge to the standard ΛCDM cosmological model. In this work, I present new results from the Carnegie Supernova Project, where we determine H₀ across both optical and near-infrared bandpasses (uBgVriYJH). We calibrate SN Ia luminosities using three independent distance indicators: Cepheid variables, Tip of the Red Giant Branch (TRGB) stars, and galaxy surface brightness fluctuations (SBF). By combining all calibrators, we obtain H₀ = 71.76 ± 0.58 (stat) ± 1.19 (sys) km s⁻¹ Mpc⁻¹ in the B band and H₀ = 73.22 ± 0.68 (stat) ± 1.28 (sys) km s⁻¹ Mpc⁻¹ in the H band. These values lessen the currently reported early- vs late-Universe H₀ tension when compared at the level of statistical uncertainties alone.

ABSTRACT. Type Ib and Ic supernovae (SNe Ib/c) mark the end points of massive stars that have lost their hydrogen envelopes, providing important constraints on the mass-loss history of massive stars. Despite their importance, their progenitor structures remain uncertain, including the long-standing hidden helium problem. Using data from the Zwicky Transient Facility (ZTF), we show that SNe Ib and Ic exhibit a systematic difference in their optical colors near peak brightness. SNe Ib are, on average, bluer than SNe Ic at a statistically significant level. Through radiative-hydrodynamics light-curve modeling, we show that this color difference arise from differences in ejecta composition, reflecting different progenitor structures: helium-rich progenitors for SNe Ib and helium-poor progenitors for SNe Ic. Our results suggest that optical colors might serve as a powerful tool for maximizing the scientific impact of LSST by supporting event characterization, enabling photometric classification, and providing population-level constraints on supernova progenitors.

ABSTRACT. Gamma-ray bursts (GRBs) are the most extreme cosmic explosions and emit across the entire electromagnetic spectrum, from TeV gamma rays down to sub-GHz radio frequencies. Their multi-wavelength emission allows for studies of ultra-relativistic jets, extreme particle acceleration, the final stages of life for the most massive stars, and the counterparts to gravitational wave events. Radio observations play a crucial role in probing GRB physics, tracking the evolution of the broadband spectrum for much longer than any other spectral regime and catching early-time phenomena such as the reverse shock that often go undetected at higher wavelengths. In recent years, there has been a paradigm shift in radio observations of GRBs, due to significant increases in sensitivity and the implementation of automated triggering at large radio interferometers. We will present highlights from the PanRadio GRB program, which aims to perform an unbiased radio survey of Southern Hemisphere GRBs using the Australia Telescope Compact Array (ATCA). Using the ATCA rapid-response mode, we have obtained the earliest radio detections of GRBs to date, within the first hour post-burst. It has revealed temporal behaviour never seen before from unusual central engine behaviour. We also demonstrate how multi-frequency and multi-timescale observations can reveal insights into GRB jet geometry and its environment. We will discuss how the capabilities developed in our PanRadio GRB program can be adopted in the SKA/ngVLA/DSA-2000 era of radio telescopes.

ABSTRACT. Due to the advancement in technology, the amount of data in Astronomy has increased exponentially. Astronomical object classification by eye has become impractical, especially in big surveys. Therefore, machine learning based classification has now played an important role in Astronomy studies. Variable stars whose brightness changes over time are common objects studied in such big surveys. By studying properties of different types of variable stars, we can learn about the system that they are in, such as distance, age, metallicity, and reddening. Unlike traditional classification methods that solely rely on numerical photometry data, in this work, we use the image of a phase-folded light curve to train the classification model. The light curves will be constructed using two different methods, which will then be separately trained. The predictions from the two models are then integrated to enhance predictive performance. Although the data used in this work is from ASAS-SN, the results of this study can also be applied to data from other surveys and even other similar classifications.

ABSTRACT. Recent developments in observations have led to a high volume of data. Astronomers have now turned to machine learning to facilitate various tasks in Astronomy research. One such task is variable star classifications. Traditionally, we would need to extract features from light curve data before classification. In this work, we are exploring classification directly from observed images. We will use Full-Frame image data from TESS. From these multi-frame images, we will apply a two-stream Convolutional Networks (ConvNets) architecture with spatial and temporal networks. The pattern of optical flow from this step will then be used to train the diffusion model to learn the changing pattern of stellar brightness with time. Both the ConvNets and diffusion model have been found to increase the efficiency of data classification, especially with sparse and inconsistent interval data. Furthermore, the generative capability of the diffusion model allows the synthesis of additional samples for minority or rare classes of variable stars, contributing to a more balanced dataset and improving the classification accuracy for underrepresented groups. This will not only improve the overall performance of the classification but also allow us to directly classify variables from images without the need for extracting light curves.

ABSTRACT. Optics-based observational astronomy has long been a cornerstone of cosmic exploration. Computational optics enables observation beyond traditional lens-based systems. We present a light-field meta-imaging sensor with digital adaptive optics and RAFAEL, a snapshot spectroscopic chip that transforms spectroscopy into a full-field, time-domain observable. By collapsing scanning into single-shot acquisition, RAFAEL enables orders-of-magnitude gains in survey efficiency and high-cadence hyperspectral imaging. These advances demonstrate how computational optics can reshape astronomical observation across space and time.

ABSTRACT. The Rubin Observatory LSST will start its full operation in 2026, and is expected to produce millions of alerts every night. Among numerous types of transients and variable stars, accreting white dwarf binaries, known as cataclysmic variables (CVs), are expected to be the most dominant population in Galactic sources. Due to the accretion processes in an accretion disk and onto the white dwarf, CVs show various activities in wide ranges of amplitudes (0.01--15 mag) and timescales (seconds--decades) in optical bands. We here have performed mock observation simulations to characterize the LSST discovery spaces of three subtypes in CVs. Our simulations have employed the planned cadence and depth of LSST and a thin-disk approximation of the CV distribution in our Galaxy. We found that only 20% of WZ Sge-type dwarf novae systems, representing the most energetic disk-driven outbursts in CVs with an outburst amplitude of ~8 mag and duration of ~a month, will be detected during outbursts by LSST. Given their large outburst amplitude, only those brighter than 17.5 mag at outburst maximum are expected to have an r-band counterpart in individual scans before the outburst. Thanks to the planned cadence of the LSST towards the Galactic center, ≈70% of the simulated outbursts will be detected twice or more on the discovery night. Two-thirds of these detections will be observed in different bands within an hour, providing color information rather than a rise/decline timescale in intranight. Polar subclass of magnetic CVs, characterised by 2--4 mag long-term modulations, can be unbiasedly recovered down to 22.5 mag with more than 100 detections over 10 years of the LSST operation, enabling the study of their state changes. We also find that the detection rate of the fast (<1 d) micronova bursts found in some intermediate polars is 2.6%. These will be observed as a ≥ 0.4 mag-amplitude and ≤ 1-d duration spike in the long-term light curve. The deep limiting magnitudes of LSST also provide a good opportunity for systematically studying normal CVs beyond the disk population, including globular clusters and Magellanic Clouds. Their star formation history and environment, which differ from those in the solar neighborhood, provide unique test cases for disk instability and binary evolution models. Overall, our results inform how to organize follow-up observation strategies on CVs and other transients.

ABSTRACT. Synthetic data generation has become an important tool in astronomy research, especially when real observations are limited or difficult to obtain. This study explores methods for creating high-quality synthetic data to improve the classification of variable stars. Our approach uses statistical features extracted from photometric time series data through the FEETS package. We investigate different generation techniques to create synthetic data, which is then used to train machine learning classification models. To evaluate the effectiveness of this method, we conduct experiments on a subset of the All-Sky Automated Survey for Supernovae (ASAS-SN) dataset. This research aims to demonstrate that well-designed synthetic data can enhance classification performance compared to traditional numerical-based methods, improving both accuracy and model generalization, particularly when working with limited real observations.

ABSTRACT. To statistically investigate the star formation process in the Galaxy, we initiated the ALMA-ATOMS/QUARKS survey programme at ALMA, which observed about 140 high-mass proto-clusters at band 3 and band 6 under an angular resolution of ~0.3 arcsec. The main science goals of the ALMA-ATOMS/QUARKS survey project are: (i) to deepen the understandings of the dense gas star formation law by studying the spatial distributions of various dense gas tracers in a large sample of Galactic clumps and evaluating how much of molecular gas is participating in star formation; (ii) to investigate how stellar feedback from formed OB (proto)stars influences the surrounding gas distributions and the next generation of star formation in their natal clumps; (iii) to resolve filaments and to study their roles in protocluster formation. I will talk about the current status of this survey and future plans.

ABSTRACT. Stars ubiquitously lose mass before they evolve to their end states. Depending on the stellar mass and evolutionary stage, the mass loss manifests in different ways. For massive stars, mass loss can be detected as IR dust emission from red supergiants (RSG), and circumstellar bubbles around Wolf-Rayet (WR) stars, luminous blue variables (LBVs), and blue supergiants (BSGs). For intermediate- and low-mass stars, the mass loss produces the commonly observed planetary nebulae (PNe). Besides these known manifests of stellar mass loss, are there other observable products of mass loss?

The Dark Energy Camera Magellanic Clouds Emission-Line Survey (DeMCELS), with a seeing-limited angular resolution of ~1.4 arcsec and a coverage of H-alpha, [O III], and [S II] nebular lines, has provided an excellent opportunity to search for ionized nebulae with sizes up to a few pc in the Magellanic Clouds (1" = 0.24 pc in the LMC and 0.29pc in the SMC). While such small nebulae in active star-forming regions are likely compact HII regions, those in isolated environment are candidates for circumstellar nebulae. We are particularly interested in the candidate circumstellar nebulae that are not associated with known massive stars and are not cataloged as PNe.

We have examined the entire SMC and the preliminary results will be reported in this talk. A variety of small nebulae are found. Some have no obvious central stars, and some appear to be associated with stars that are not expected to be able to photoionize surrounding gas. The most exciting group of objects are small nebulae around eclipsing binaries, although they may or may not originate from the same mass loss mechanism.

ABSTRACT. We report the discovery and spectroscopic investigation of a new supernova remnant (SNR) candidate, G25.8+0.2, identified in the UKIRT Wide-field Infrared Survey for Fe+ (UWIFE). The source was initially detected as extended [Fe II] 1.644 μm line emission exhibiting a partial shell morphology within the G26 star-forming complex. To investigate its origin, we obtained high-resolution H- and K-band spectra using the Immersion Grating Infrared Spectrometer (IGRINS). The spectra reveal distinct kinematic components with markedly different [Fe II]/Brγ ratios. The high-velocity component shows enhanced [Fe II] emission indicative of shock excitation, while the low-velocity component is consistent with photoionized gas associated with an H II region. The shock-excited [Fe II] filaments closely trace a bright radio shell and are spatially connected to molecular material in the region. The kinematic separation between shock-ionized and photoionized gas supports the interpretation that the observed [Fe II] emission originates in J-type shocks propagating through circumstellar or interstellar material, with the remnant embedded in a massive star-forming complex. This study demonstrates the effectiveness of [Fe II] imaging surveys combined with high-resolution near-infrared spectroscopy in identifying obscured SNRs in the inner Galaxy.

ABSTRACT. Massive stars are the engines of cosmic evolution, producing neutron stars, black holes, supernova explosions, and the heavy elements that shape galaxies. Yet their final fate remains uncertain due to the complex interplay between stellar mass, metallicity, and rotation. In this talk, we present new insights from an extensive grid of stellar evolution models covering initial masses from 9–500 M☉ and metallicities from Z = 10⁻⁵ to 0.02, comparing rotating and non-rotating stars. We demonstrate that stellar rotation significantly reshapes the boundaries between neutron-star and black-hole formation and strongly modifies the black-hole mass spectrum, particularly at low metallicity. Our results predict a revised pair-instability mass gap between approximately 90 and 150 M☉ and provide a natural framework for interpreting recent gravitational-wave detections. We conclude by discussing the broader implications for early-Universe stellar populations, supernova demographics, and the cosmic growth of black holes

ABSTRACT. Hot subdwarf B stars are evolved stars that formed through binary interactions, namely through mass transfer from a red giant branch star or through stellar mergers. Their evolutionary and chemical properties were largely studied in the literature, however, their rotational properties were not thoroughly studied. Moreover, thanks to space telescopes (such as Kepler and TESS) it has been possible to probe the rotation of their deep stellar interiors through methods from asteroseismology.

In this talk I will present the first grid of stellar evolution models of hot subdwarf B stars with rotation and internal magnetic fields (Moyano et al., in prep.) and I will discuss how our models compare to observational measurements, in particular those from asteroseismology. In brief, we found a large disagreement between the most refined theories on internal angular momentum transport and observational data, for which we propose a transient phase in which these stars accrete matter through remnant circumbinary disks that remained from their formation. Moreover, I will discuss how these models can be extended to study the rotation of white dwarfs, for which ample photometric and asteroseismic measurements of their internal and surface rotation rates are available in the literature.

ABSTRACT. Massive stars eject strong winds that affect their evolution. When in a binary system, their winds collide and emit radiation across the spectrum, providing an opportunity to study the stars and the interaction between them. There are many physical effects involved in the colliding wind problem, and its complexity requires 3D numerical simulations. I will present simulations of colliding winds in massive binary systems that include a detailed treatment of wind ejection, orbital motion, clumpiness, and other effects. I will discuss the results of systematic simulations that were used to determine the general conditions that may lead to accretion onto the star with the weaker wind, and demonstrate new relationships between the mass accretion rate and the ratio of the stellar wind momentum and the Bondi–Hoyle–Lyttleton accretion rate. Additionally, I will present simulations of mass ejection during giant eruptions in LBVs, including interactions and accretion onto the companion star, and discuss the implications for the formation scenario of LBVs. I will also present new stellar evolution simulations revealing the effects of mass ejection and mass accretion at high rates on massive stars.