ABSTRACT. The diversity of Fast Radio Bursts' (FRB) characteristics has spurred speculation of their being of diverse origin. The FRB 20200428 is identified with a magnetar, generally considered a young neutron star. FRB 20200120E is identified with a globular cluster, which should host only old stellar populations. We propose an alternative explanation, where the diversity traits correspond to different ages of a single population. Most, if not all, FRBs originated from a supernova explosion that ionized its environment to produce the persistent radio source (PRS) counterpart. FRB sources evolve rapidly in early stages. We have just published the first evidence of robustly decreasing DM in a repeater (Niu et al. 2026), based on over 4 years of monitoring of FRB 20190520B. A young supernova remnant depicts such evolution well. The further evolution will clear up the environment, making the PRS disappear. The FRB source will become less active and eventually be identified as an apparent single-burst source.

ABSTRACT. We introduce a novel method to constrain the Hubble constant (H0) by combining fast radio bursts (FRBs) and their persistent radio sources (PRSs) through the observationally validated Yang relation, Lν ∝ ∣RM∣, which links PRS luminosity to the rotation measure of the associated FRB. Using a mock sample of PRSs, we demonstrate that the Yang relation can help to unravel the degeneracies among H0, baryon density parameter Ωb, and baryon fraction in the intergalactic medium fIGM in the traditional approach of using dispersion measure only to perform cosmological analyses. Our method employs a two-stage Markov Chain Monte Carlo analysis to constrain H0. Using the available data of six observed PRS systems, we obtain a preliminary constraint of H0 = 75 ± 30 km s−1 Mpc−1. We briefly discuss possible refinements of the method by reducing residual degeneracies and systematic uncertainties using future data and physical modeling. Our results indicate that the Yang relation can potentially become a new probe for performing FRB cosmology.

ABSTRACT. The origins of fast radio bursts (FRBs) remain uncertain, although magnetars are a leading progenitor candidate. Because magnetars are thought to form primarily through core-collapse supernovae in young stellar populations, the discovery of FRB 20200120E in a globular cluster (GC) in the nearby galaxy M81 was unexpected given the ancient stellar populations of GCs. Expanding the sample of FRBs localised to nearby galaxies is therefore essential for testing FRB formation channels in old stellar environments. M49 (NGC 4472) is a nearby (≈17 Mpc), radio-quiet giant elliptical galaxy in the Virgo cluster hosting an extensive GC system (≈7000 GCs), making it an ideal target for GC FRB searches. We conducted a 9-hour SnapShotCal observation of M49 using the Five-hundred-meter Aperture Spherical Telescope (FAST) 19-beam receiver, covering approximately 4200 GCs (2.25 hr per pointing), and performed a comprehensive single-pulse search with TransientX over a dispersion-measure range of 0-5000 pc cm^-3. No unambiguous astrophysical FRBs were detected. The most significant trigger reached a post-processed signal-to-noise ratio of 8.6 sigma at a dispersion measure of 412.2 pc cm^-3, but is statistically consistent with thermal noise after accounting for the false-alarm rate. Using the radiometer equation, we derive a peak flux-density sensitivity of ≈25 mJy (fluence limit ≈25 mJy ms for a 1 ms burst) and place an upper limit on the FRB occurrence rate of 3.9x10^-4 FRB GC^-1hr^-1. Our non-detection suggests that FRB production in GCs is rare, episodic, or limited to exceptional systems such as FRB 20200120E, supporting scenarios in which the dominant formation channel is linked to young magnetars in star-forming environments.

ABSTRACT. We are conducting the Galactic Plane Pulsar Snapshot (GPPS) survey using the Five-hundred-meter Aperture Spherical radio Telescope (FAST). To date, the survey has discovered 835 pulsars, including more than 190 millisecond pulsars and approximately 170 binary systems, as well as 9 fast radio bursts (FRBs). In addition, we have re-detected over 1,000 previously known pulsars. This unprecedented sample size enables a revised determination of the low-luminosity end of the pulsar luminosity function, thereby revealing a substantial population of intrinsically faint and weakly emitting pulsars. We found that at least 15% of them are neutron stars only occasionally radiate pulses. Among these newly discovered objects are several pulsars in compact binary orbits—including one with an orbital period of just 53 minutes, one exhibiting the highest measured orbital eccentricity to date, and one likely hosting a helium-star companion.

ABSTRACT. The historic discovery of gravitational waves through direct detection by the LIGO observatories in the USA, in principle, opened up a new window to the cosmos. In practice, however, the true launch of gravitational-wave astronomy will await a capable global array of LIGO-like observatories, including the LIGO-India observatory under construction in India. The talk will outline the promise of GW science across the entire GW spectrum, and the growing Indian involvement and aspirations in this new frontier of Astronomy.

ABSTRACT. A decade since the field of gravitational-wave astronomy became an observational reality, the scientific impact of these new messengers has become abundantly clear. These include new ways to probe general relativity, stellar physics and stellar evolution, galactic and extragalactic astrophysics, nuclear astrophysics, and even provide independent cosmological measures free of the cosmic distance ladder. The global community is therefore driving forward designs for next generation gravitational-wave observatories, which will be able to see every neutron star and black hole merger throughout the Universe, as well as hopefully uncover supernovae physics and the physics of rapidly rotating neutron stars. Australia and the broader Asia-Pacific region's contribution to the global gravitational-wave effort is immense, and only getting stronger. In particular, we are now driving forward the case to build one such observatory in the region, which will necessarily require large international partnerships. In this talk, I will discuss the scientific impact of the next generation of gravitational-wave observatories, including the substantial benefit of housing one in the Southern Hemisphere. I will also focus on the significant collaboration opportunities throughout the region in terms of infrastructure, technology, and astrophysics.

ABSTRACT. Gravitational waves have been detected from the inspiral and merger of neutron star systems, and such detections provided valuable insights into fundamental physics like the nuclear equation of state. Meanwhile, searches for gravitational waves from non-merging neutron stars continue, where detections could yield far more than from mergers. Contemporaneous electromagnetic tracking of a pulsar's rotation permits the most sensitive of these searches by greatly reducing search parameter spaces. Here I discuss our campaign to track the long-term evolution of the rotation rate of fast-spinning young neutron stars. These sources are only observable in X-ray and primarily made use of NICER on the International Space Station. I describe some of the sources we monitored, a few results from our observations, including glitches and what they tell us about superfluidity, and what could be learned from gravitational wave detection. If available, results from searches of the latest gravitational wave data may also be presented on behalf of the LIGO-Virgo-KAGRA Collaboration.

ABSTRACT. General relativity predicts that gravitational waves (GWs) carry linear momentum. Consequently, the merger of a binary black hole (BBH) imparts a recoil (or “kick”) to the remnant of crucial implications in, for example, black-hole formation scenarios. While the magnitude of the recoil can be inferred from the binary’s mass ratio and spins, determining its direction requires resolving the two orientation angles of the source. In this talk, I will demonstrate how the phase angle can be measured from GW signals in the presence of higher-order harmonics and then be exploited to determine the recoil direction, opening new avenues for probing post-merger dynamics.

In dense environments such as active galactic nucleus (AGN) disks, a merging BBH embedded in the AGN disk can produce a luminous flare from the Blandford–Znajek (BZ) jet of the remnant, or from the kicked remnant interacting with the surrounding gas. Conventional assessment of associating the GW signal with its potential electromagnetic (EM) counterparts has been restricted to temporal and spatial localisation. Different emission mechanisms, however, impose different observability constraints on the remnant black-hole properties, which are observables from GWs. I will present a statistical framework that integrates the remnant spin and recoil. In our work, we apply this framework to assess the consistency of the GW190521-ZTF19abanrhr pair with two types of emission processes: a BZ jet closely aligned with the final spin axis and a diffusive, isotropic flare. Combining with the odds for a common 3D sky-location, Ω, we obtain the posterior odds for a true GW-EM coincidence as log₁₀(O_{Ω, jet}) = -1.17 and log₁₀(O_{Ω, jet}) = -0.39 opposed to a random one. Our method leverages a previously unexplored perspective to assess GW–EM associations and will allow constraints on both the physics powering flare mechanisms and the properties of AGNs.

ABSTRACT. Calculation of likelihood that a detected gravitational signal is the same signal that we expect to theoretically detect for any particular system with some source parameters, requires calls to theoretical waveform approximations. This likelihood has to be calculated with around a million theoretical waveforms belonging to different sampled sets of parameters from the chosen parameter space. This task is computationally expensive and time consuming, especially for cases where the binary sources have complicated characteristics or when marginalized single parameter estimation is desired, for instance, for the luminosity distance to the source. I will introduce some encoder-decoder style neural network models that we have developed to solve these issues and yield fast and accurate approximations of gravitational waveforms.

ABSTRACT. Recent observations have revealed a surprisingly large population of galaxies at very high redshifts. In this talk, I will present results on the UV galaxy luminosity function at z≳8 and discuss key methodological and interpretive challenges, with a particular focus on constraints at the bright end. I will also discuss the role of completeness simulations and show how they can be extended to improve constraints on galaxy clustering measurements. In addition, I will demonstrate how constructing luminosity functions in multiple rest-frame optical bands provides complementary constraints on galaxy evolution models. Finally, I will introduce a simple calculator to estimate brown-dwarf contamination in high-redshift galaxy samples and illustrate how it can be used to better the prioritization of spectroscopic follow-up observations.

ABSTRACT. Resonant and fluorescent lines serve as powerful diagnostics of the interstellar and circumgalactic media of galaxies. Because their propagation through gas is inherently complex, interpreting their observational signatures—whether seen in absorption or emission—is often challenging. Numerical radiative transfer simulations are therefore essential for accurately modeling the transport of resonant-line photons in both physical and frequency space, and for generating realistic mock observations. We present LaRT, a three-dimensional radiative transfer code designed to simulate the propagation of resonant and fluorescent lines in astrophysical environments. The code handles a wide range of resonance and fluorescence transitions, including Mg II, Fe II, Si II, Na I, and H₂ lines, and incorporates quantum-mechanically derived scattering phase functions for improved physical accuracy. We demonstrate how LaRT can be used to produce mock observations that can be directly compared with real data.

ABSTRACT. We explore the star formation history of nearby galaxies using data from the Spectro-Photometer for the History of the Universe, Epoch of Reionization, and Ices Explorer (SPHEREx). The linear variable filter (LVF) imaging of SPHEREx provides spatially resolved, low-resolution spectra of nearby galaxies. We utilized a machine learning algorithm, the Histogram-based Gradient Boosting Regression Tree (HG-BRT), to build models predicting stellar metallicity and population age. Using the TNG50 simulated data at snapshot 98 (z=0.01), we generated mock datasets for galaxies with radii greater than 10 kpc (corresponding to ~ 7.6 pixels at z=0.01), stellar masses between 10^9 and 10^11 solar mass. These datasets include surface brightness maps in 36 channels covering the wavelength range of 0.75-5 μm, along with corresponding metallicity and age maps. Our models were trained on SPHEREx photometry (input) to predict mass-weighted metallicity and age (output) via pixel-by-pixel learning. From our models, we can reconstruct spatially resolved metallicity and age maps. The models achieve median absolute errors (MAEs) of 0.05 dex for metallicity and 0.02 dex for age. We applied our models to real observations for NGC 1087, NGC 1300, NGC 1672, NGC 2385, and NGC 4254. The resulting radial profiles track the trends derived from the PHANGS survey. This framework can be extended to a larger sample of nearby galaxies to statistically study galaxy growth history as a function of morphology and environment.

ABSTRACT. The absolute neutrino mass scale remains one of the central open questions at the interface of cosmology and particle physics. Recent DESI DR1/DR2 results suggest subtle departures from the standard ΛCDM model and highlight the limitations of relying exclusively on two-point statistics to constrain the total neutrino mass. The emergence of controversial “negative neutrino mass’’ estimates further underscores the need for more robust probes of the underlying density field. In this talk, I introduce alternative higher-order clustering approaches based on cosmic-web analysis, including critical-point statistics and persistent homology. These techniques, which capture complex features of large-scale structure, access information inaccessible to traditional methods and are intrinsically sensitive to the imprint of massive neutrinos on structure formation. Supported by state-of-the-art cosmological simulations, they offer a powerful framework to enhance our sensitivity to neutrino effects in forthcoming data. These novel tools are particularly timely for current and next-generation wide-area surveys—DESI, Euclid, and Rubin-LSST—where they provide promising pathways toward a direct and reliable detection of neutrino mass, as well as improved constraints on its total value and hierarchy.

ABSTRACT. The radial distribution of metals in galaxies provides important insight into their formation and evolution history, tracing gas inflows and outflows as well as the impact of feedback processes. We examine gas-phase metallicity gradients in a large sample of star-forming galaxies and AGN-host galaxies using strong emission-line diagnostics. By studying the radial distribution of gas-phase metallicity as a function of normalized galactocentric radius, we aim to characterize the chemical structure of galaxies and explore how nuclear activity relates to the distribution of metals within their host systems. We also consider the role of environment by examining systems showing signatures of interactions or mergers and galaxies associated with extended tidal structures. This comparison places AGN-host galaxies within the broader framework of galaxy chemical evolution and helps assess the role of nuclear activity in shaping their chemical structure. I will discuss how these results provide insight into the interplay between star formation, gas dynamics, and black hole activity in galaxy evolution.

ABSTRACT. The JWST era has unveiled a population of enigmatic high-redshift sources, including Little Red Dots (LRDs) and AGN candidates, whose nature is obscured by the limitations of traditional rest-optical classification schemes like the BPT diagram. We present a novel, machine learning based approach to galaxy classification using a phylogenetic tree constructed from the latent space of an autoencoder (AE). We trained the AE with rest-frame SDSS spectra at 0<z<0.3, lowering their resolution to JWST NIRSpec PRISM equivalent. The phylogenetic tree naturally segregates Seyfert, LINER, star-forming, and composite galaxies into distinct evolutionary clades. The structure of the tree correlates with various physical properties such as stellar mass, emission line ratios, and morphology. Notably, it reveals a "bridge structure" among Seyfert galaxies, capturing an evolutionary sequence within. To address the challenges of cosmic dawn, we apply this phylogenetic framework to classify high-redshift (4<z<7) AGN from JWST observations with rest-frame NIRSpec PRISM spectra resolution. These sources robustly populate the AGN clades, validating the method's redshift independence. Furthermore, we place LRDs onto the tree, finding they consistently reside within AGN clades, strongly supporting their identification as AGNs. This phylogenetic framework provides a powerful, redshift-independent tool for classifying the growing zoo of high-redshift JWST sources. It places seemingly disparate populations like LRDs into a unified evolutionary context, offering a new path to understand the co-evolution of the first galaxies and their central black holes.

ABSTRACT. A total solar eclipse will cross Australia on Saturday 22 July 2028 with three more in 2030, 2037 and 2038. The path of totality crosses the north of Western Australia, across the middle of the Northern Territory, the western corner of Queensland then right across NSW including Sydney, Australia's largest city. Totality lasts from over 5 minutes in the west to 3 minutes over Sydney. 6.7 million people live directly under the path of totality whilst everywhere in the country will experience at least a partial eclipse. Realising the potential of this as a national STEM opportunity and public event the Astronomical Society of Australia established an Eclipse Working Group in 2024. The EWG comprises several panels including Safety, Communications, Education, and others. A website is already established and the information online will grow as resources are developed: https://eclipse.asa.astronomy.org.au/ Preparations for such an event are complex and involve discussions and notifications with many bodies including Federal, State and Local governments, police, education authorities, sporting bodies, Indigenous communities and many more. Safety has been identified as a key priority, working with standards agencies, ophthalmologist and optometrists to ensure safe standards and messaging for how to view the eclipse safely. The eclipse provides an exciting opportunity to engage the public and students across the nation so relevant resources need to be developed and disseminated. Teacher training has been identified as a key method to aid this so planning has commenced to roll out professional development across the country from 2027. Our EWG is fortunate to be able to draw on the expertise, experience and resources of organisations such as the American Astronomical Society and the Astronomical Society of the Pacific from the recent north American eclipses. As previous eclipses have shown, tourism, both local and international, will be massive for such an event, especially as it can be viewed easily from a major city, Sydney, weather permitting. Liaison with tourism authorities across the path of the eclipse will be vital. The EWG structure, membership, issues identified and challenges to be tackled are discussed. We invite you to start planning for your trip to Australia in 2028.

ABSTRACT. Planetariums are among the most effective tools for fostering engagement and conceptual understanding in astronomy. However, the high cost of conventional dome systems limits access, particularly in developing regions and rural schools across the Asia-Pacific. This workshop introduces a scalable, low-cost DIY planetarium model designed to democratize immersive astronomy education. Participants will collaboratively construct a modular geodesic dome made from triangular cardboard panels and assemble a spherical mirror projection system capable of producing fulldome visualization. The system operates with freely available software such as Stellarium enabling real-time sky simulation, interactive instruction, and fulldome media playback. The setup is portable, easy to reproduce, and adaptable for classrooms, outreach programs, science festivals, and traveling exhibitions. Since 2022, the model has been implemented by NARIT (National Astronomical Research Institute of Thailand) National Astronomical Research Institute of Thailand in more than 170 partner schools, demonstrating its practicality, affordability, and educational impact at scale. By the end of the workshop, participants will gain the technical knowledge and operational framework necessary to establish similar low-cost immersive systems within their own institutions, contributing to more equitable access to astronomy education across the region.

ABSTRACT. Compared to many other regions, Southeast Asia still lacks many astronomy infrastructures. Yet, the interest in astronomy is quickly emerging and many new advancements is being made in both facilities such as telescopes, planetariums, and the engagements with the public. The unique challenges each countries face in engaging with the public in an emerging countries often results in unique solutions that could be fundamentally different from those found in developed countries. However, one might find that these challenges and solutions might be more common with other countries in the region.

The Southeast Asia Planetarium, Education, and Outreach Conference (SEA-PEO) aims to bring together like-minded individuals around Southeast Asia to share their common struggles and solutions often find in the region. It has the goal to bring activities that are highly relevant to the cultural context, while introducing new ideas and making the region recognizing its own potential. This conference was held for the first time ever in November 25-28, 2024 and was met with overwhelming interest with applications from over 250 participants from over 24 countries within and outside of Southeast Asia. The overwhelmingly positive feedback from the participants highlight the needs for such conference where content are tailored with high adaptability and relevancy to the participants in mind. Moreover, this also advocate for conferences that directly address the cultural preference in Asia that might set itself apart from the western culture.

ABSTRACT. The Southeast Asian Astronomy Network (SEAAN) emerged from a foundation of friendship, mutual trust, and a shared aspiration to strengthen astronomy across Southeast Asia. What began as informal connections among colleagues who supported one another in research, training, and resource sharing has evolved into a structured regional mechanism that drives scientific collaboration and development in the region. SEAAN provides a platform where countries at different stages of development help each other overcome challenges, share practical solutions, and grow together—an approach especially valuable for nations facing similar technological or institutional limitations. As part of this collective effort, the National Astronomical Research Institute of Thailand (NARIT), as the host of the Southeast Asian Regional Office of Astronomy for Development (SEA-ROAD) under the Office of Astronomy for Development (OAD), plays a crucial coordinating role and ensures that astronomy contributes meaningfully to sustainable development across the region.

SEAAN facilitates joint research initiatives, capacity-building programs, and shared access to telescopes, instrumentation, and data, thereby enhancing scientific capabilities throughout its member countries. It supports the development of young astronomers, engineers, and science communicators through training opportunities, mobility programs, and international partnerships. Beyond scientific collaboration, SEAAN actively promotes outreach and unifying engagement, inspiring greater scientific curiosity and strengthening the role of astronomy in society. As it continues to grow, SEAAN stands as a testament to how developing countries can combine their strength and can evolve together into a powerful regional framework that transforms shared ambitions into collective progress in using astronomy to achieve sustainable development in Southeast Asia.

ABSTRACT. Astronomy education has received more interest in recent years, with growing demand for professional astronomical resources. However, accessibility gaps remain a recurring problem in many regions around the world. To help bridge this gap and promote equal access to educational opportunities, the ITCA Teacher Training Workshop was developed for international audiences. The primary objective of this workshop is to equip educators as key contributors to passing on knowledge to future generations with practical tools, accurate content, and inclusive approaches to improve astronomy instruction in diverse classroom settings.

Many educational systems and cultures, particularly in developing countries, still rely on traditional, passive learning methods that struggle to keep up with the needs of today’s learners. As such, hands-on and active learning activities, connecting astronomy to real-life experiences relevant to teachers and students are keys to implementing impactful changes to the participants. For instance, reconceptualizing familiar phenomena through an activity comparing themselves to the Earth to learn the moon phases more clearly. Realizing the vast scale of the solar system simply by walking through a scale model. The materials used in all activities are widely available and easily adaptable with local resources—ensuring that teachers could confidently bring these activities into their own classrooms. The workshop has been conducted with collaboration with local partners across Southeast Asia, including Laos, Myanmar, Malaysia, Timor-Leste, Singapore, Indonesia, and Vietnam. It has also expanded to other regions, such as Nepal and Botswana.

Participants gained effective and accurate methods for communicating astronomy in simple and accessible manners, and they were inspired by unique experiences and fresh ideas that they can apply and implement in their instructional contexts—passing on knowledge from generation to generation. These outcomes help ensure that astronomy can connect people across borders in a sustainable way. Future collaborations with interested partners from around the world are welcomed, with the aim of continuing to encourage educators globally, aligning with NARIT’s mission “Leave no one behind.”

ABSTRACT. This abstract highlights the importance of developing a website framework that is tailored, specific, and built in-house for the Office for Astronomy Outreach of the International Astronomical Union. Its purpose is to support the creation of educational materials, public resources for the development of scientific knowledge, and initiatives that promote astronomy in places that lack free access to it.

Throughout 2024 and 2025, the OAO implemented a series of internal reforms aimed at improving the distribution of material, educational, and communication resources for all events and for the network of National Outreach Coordinators it supports. Within this new structure, we proposed the design, development, and production of a new web platform intended for use by the general public, our outreach network, and the OAO itself. Additionally, the platform needed to provide statistics and results by region, date, and type of activity in order to conduct reliable, data-driven analyses. These analyses would then inform improvements to the structure of the international NOC community, help identify recurring challenges, and support the evaluation of astronomy outreach activities at a global scale.

All of this is grounded in the development of an internally built database within the OAO website, created through a process of content organisation, analysis, and the design of an architecture capable of collecting data securely, efficiently, and in accordance with international established parameters. This work lays the foundation for a new approach to research in astronomy communication and the communities it serves.

ABSTRACT. Space debris is an important factor affecting the long-term sustainability of outer space, and the prosperity of space activities inevitably leaves space debris in outer space. In order to better mitigate the trend of continuous growth of space debris and avoid the threat of space debris to the safety of spacecraft flight and the safety of outer space activities, we need to master the orbit and related characteristics of all space debris. This report introduces NAOC work on space debris observation, orbit determination, prediction, etc., and introduces the basic public database of space debris that can be used for related scientific research, algorithm verification, and data exchange, as well as the concept and practice of the Space Debris Data Alliance launched by NAOC.

ABSTRACT. Space systems are vital for the future of humanity, but the rapid growth of the space industry is endangering that future, in-orbit and on Earth. From the in-orbit impact of space debris, to the in-atmosphere impact of launch; from the terrestrial impact of industrial mining, to the light and radio pollution of our skies, this once niche industry is now having a measurable global impact. Our research has shown that discussions of ‘Space Sustainability’ prioritise expert perspectives and abstract impacts; we struggle to articulate the real, human impact of our growing industry, and foster inclusive discussions about how to tackle these sustainability challenges. At the University of Manchester, we are developing models that can provide a holistic understanding of the impact of our global space industry and put people at the centre of the discussion. In this talk we will show our augmented reality model of space, which can allow people to see the full extent of satellites in orbit, and experience what our future night sky might look like if growth of the space industry continues without mitigation. By integrating our sustainable design research within the tool, we can understand how design choices and regulatory changes made today can go on to shape a sustainable space future. By providing these visions of possible space futures, we aim to support development of technologies and techniques that can provide a step-change in sustainable space mission design.

ABSTRACT. In the current context of the rapid growth in satellite launches and orbital objects, it is crucial to precisely understand the space object population and its evolution over time. Satellites and space debris represent a growing concern for astronomers and an increasing risk for space operators.

This work presents a pipeline developed to detect space objects in archival data from large field-of-view telescopes, focusing specifically on the VST/OmegaCAM dataset. Our aim is to reliably identify objects serendipitously captured by the OmegaCAM imager, assess their impact on VST’s scientific operations, and prepare detections for photometric studies to characterize the objects.

We describe the adapted deep learning architecture used for streak detection in astronomical images, along with the datasets employed for training, validation, and testing. Additionally, we introduce a convolutional neural network classifier trained to distinguish true detections from false positives. Using this pipeline, we analyze five years of OmegaCAM data.

The detection algorithm achieves an F1-score exceeding 95%, and when combined with the classifier to discard false positives, the overall F1-score improves beyond 97%, demonstrating impressive reliability and detection capability. Over the five-year period, our study reveals a clear trend of increasing impact of space object streaks on scientific images, especially following the deployment of mega-constellations.

Understanding and characterizing the space object population is now more important than ever. Our pipeline serves as a valuable tool for assessing the impact of streaks on astronomical images and for detailed studies of the detected objects. It is easily adaptable to other telescopes, and in support of open science, we are making our detection results freely accessible through a web interface.

ABSTRACT. The presence of space debris and the growing number of satellites present considerable challenges to the sustainability of orbit and the safety of missions. This research explores data-driven methods for mitigating space debris and managing orbital traffic through the application of advanced data science methods, including machine learning, predictive analytics, and big-data processing. We analyze real-time observational data collected from radar, optical sensors, and satellite telemetry to enhance the detection of debris, assess conjunction risks, and improve the accuracy of collision predictions. Machine learning algorithms are used to project orbital paths, categorize debris features, and refine maneuver planning for operational satellites. Moreover, data fusion and visualization techniques improve space situational awareness by integrating diverse datasets into practical insights. The results underscore the potential of data-driven frameworks to facilitate automated decision-making, decrease operational uncertainties, and bolster long-term safety and sustainability in orbit.

ABSTRACT. Space debris laser ranging signals are easily disturbed by complex noise, and traditional filtering algorithms are difficult to extract effective data reliably. Aiming at this problem, this paper proposes an effective signal extraction method based on DBSCAN density clustering. This method uses DBSCAN to perform adaptive clustering on ranging data, which can automatically distinguish effective signals from noise and improve the extraction performance under complex noise environment. Experimental results show that the proposed method outperforms traditional filtering algorithms with simple process and strong applicability, providing technical support for space debris laser ranging data processing.

ABSTRACT. Stars like our Sun are continually forming throughout our home galaxy, the Milky Way. The Atacama Large Millimeter/submillimeter Array (ALMA), located in the Atacama Desert of northern Chile, is currently the most powerful radio interferometric array on Earth. With its unprecedented sensitivity and resolution, ALMA allows us to observe star-forming regions in extraordinary detail. In this talk, I will present our ALMA observations that reveal the earliest stages of star formation with exceptional clarity. In particular, I will discuss our findings on accretion disks and jets around forming stars and explore the physical mechanisms that govern their formation. These accretion disks are expected to evolve into protoplanetary disks, where planets eventually form.

ABSTRACT. Radio Frequency Interference remains one of the most critical challenges in the development of radio astronomy facilities, particularly in rapidly expanding regions where human activity increasingly contaminates the radio spectrum. This study addresses the need to evaluate the suitability of potential observation sites for Pusat Astronomi Borneo in establishing a Radio Quiet Zone and supporting Very Long Baseline Interferometry operations. The primary objective is to conduct a comprehensive, broadband RFI assessment covering DI, HI, OH, and CH frequencies while integrating environmental parameters to determine combined impact on radio quietness. The measurement employed a Circular Patch Antenna at Spectrum Analyzer with Data Logging System enabling continuous acquisition of peak, average and RFI variations at four selected site. Findings reveal that Tengah_PDG and Parit_Kuala possess the most favorable environmental and spectral characteristics, with RFI levels consistently below –80 dBm and minimal temporal variability, making them strong candidates for RQZ designation. This study benefits national observatory planners, VLBI network coordinators and the wider Malaysian radio astronomy community, providing a scientific foundation for long term spectrum protection and Malaysia’s strategic participation in international VLBI arrays. The methodology presented offers a replicable framework that can guide regional RFI management policies, optimize site-specific instrumentation deployment and support the advancement of radio astronomy capabilities across Southeast Asia.

ABSTRACT. Spectral line surveys are crucial to determine the chemical composition and physical characteristics of interstellar objects. We present the last results of the ultrasensitive line survey QUIJOTE carried out with the Yebes 40m telescope at millimeter wavelengths, reaching an unprecedented sensitivity of 60 µK. It has led to the detection for the first time of nearly 100 new molecules in space in the last five years, including the unexpected detection of PAHs, as well as a large number of sulphur (S) molecules. These observations are at the origin of a new golden age in astrochemistry, leading to a more accurate census of molecules present in the interstellar medium (ISM), which allows to address some of the major open questions in astrochemistry. This is the case of the sulphur depletion problem, which attempts to explain why there is an unexpected scarcity of S species in star-forming regions compared to the diffuse ISM, a mystery that has remained unresolved since decades.

Sulphur is the tenth most abundant element in the Universe and, over 330 molecules detected in the ISM, about 10% contain S atoms. Nevertheless, S-bearing molecules are not as abundant as expected in the ISM; in diffuse regions, the observed gaseous sulphur accounts for its total solar abundance, however, in dense molecular clouds and star-forming regions there is an unexpected paucity of S species. In fact, to reproduce observations in hot cores/corinos, a significant S depletion of at least one order of magnitude lower than the solar elemental S abundance must be considered. According to models, S could be locked on the icy mantles covering dust grains, however, up to date only two solid S species have been detected in space. Models and laboratory experiments also suggest that sulphur might be locked into pure S-allotropes (Sx) or into hydrogen sulphides (HxSy), but they have not been detected in dense molecular clouds up to date.

Thanks to the ultra-high sensitivity ever achieved by QUIJOTE, we have recently detected the first molecule with more than one S atom, HS2, in a dark cloud (TMC-1). We will present this result and will evaluate how this detection, together with the other fifteen sulphur molecules recently detected in TMC-1, shed light on the sulphur depletion problem in star-forming regions. We will also present recent laboratory and model results on the main formation and destruction mechanisms of HS2 in dense clouds, as well as a comparison with its oxygen counterparts since both elements share the same electron configuration. We will review how all these results significantly improve our knowledge on interstellar sulphur chemistry.

ABSTRACT. Binary post-AGB systems surrounded by compact Keplerian disks represent a key transitional phase between late stellar evolution and circumbinary disk dynamics. These evolved binaries often display a rich phenomenology involving gas rotation, dust growth, and mass outflows, reflecting the complex interplay between the central stars and their surrounding material. Understanding the physical and chemical nature of these disks is essential to trace their evolution and to evaluate their potential as cradles of second-generation planet formation.

We present new multiwavelength observations that provide a comprehensive view of the physical structure and dynamical behavior of these disk-bearing systems. Our study combines IRAM-30m CO surveys, OH maser detections with the GBT/NRAO, and detailed dust analyses from NOEMA, revealing a clear radial segregation of large and small grains, as well as chemical gradients shaped by disk irradiation and binary interaction. Fast disk winds, launched by the companion star and detected with MeerKAT, trace ongoing mass-loss channels that contribute to angular momentum redistribution within the circumbinary environment.

High-angular-resolution ALMA observations resolve the inner disk regions down to sub-au scales, unveiling asymmetric and ring-like structures associated with dust trapping and grain growth—key precursors of planet formation. These data, together with the multiwavelength observations, confirm that these long-lived circumbinary disks are not passive remnants of stellar mass loss, but active environments where the seeds of second-generation planets are forming.

Importantly, by analyzing the ratio between the disk mass and the total system mass, we identify a clear dichotomy between disk-dominated and outflow-dominated sources. Systems with a higher disk-to-total mass ratio exhibit stronger Keplerian signatures and more settled dust components, whereas outflow-dominated sources show enhanced mass ejection and turbulent gas kinematics. This classification provides a physical framework that links the observed diversity of post-AGB binaries to their evolutionary status and angular momentum evolution.

The combined new evidence from IRAM, GBT, NOEMA, MeerKAT, and ALMA reinforces this dichotomy and highlights the coupling between disk dynamics, mass-loss processes, and dust evolution. These findings position post-AGB circumbinary disks as laboratories for studying the late stages of binary evolution and the conditions under which second-generation planets may emerge from the relics of stellar mass loss.

ABSTRACT. Intermediate-mass late-B and A-type stars display a broad distribution of rotation rates and have drawn attention following the discovery of extended main-sequence turnoffs in young and intermediate-age clusters. In these systems, rapidly and slowly rotating stars preferentially populate the red and blue sides of the turnoff, respectively. While fast rotation is expected for stars with radiative envelopes, the origin of the slow-rotating population remains unclear. Proposed mechanisms include tidal braking, mergers, and pre-main-sequence (PMS) disk–star interactions. In this talk, I will present our recent work on disk and X-ray activity among intermediate-mass PMS stars in the young, massive cluster Trumpler 14. Using infrared spectral indices derived from multi-band spectral energy distributions, we identified 21 disk-bearing candidates (4 Class II and 17 Class III) with masses exceeding 1.5 M⊙, most of which lie outside the strongly irradiated cluster core. Combining these results with existing rotational-velocity catalogs, we observed that both disks and companions can contribute to angular-momentum loss at early ages. Moreover, we highlight X-ray activity during the PMS phase as an additional observational signature of high-energy processes capable of influencing the spin evolution of intermediate-mass stars.

ABSTRACT. Neutral atomic hydrogen (HI) is widely distributed throughout the universe and plays a fundamental role in galaxy evolution as well as star and planet formation. However, previous HI observations toward the Galactic Center have been constrained by low observing frequencies and limited spatial resolution, which hindered detailed investigations of the structure and kinematics of the interstellar medium. MeerKAT, a precursor to the Square Kilometre Array (SKA), overcomes these limitations with its array of 64 dishes, providing high sensitivity, excellent uv-coverage, and significantly improved angular and spectral resolution for HI studies.

In this study, we analyze high-resolution MeerKAT HI data and construct detailed maps of the HI gas distribution in the Galactic Center region. These observations enable us to probe the spatial structure, column density variations, and dynamical properties of HI with unprecedented precision. Furthermore, we identify several previously unreported point sources within the field and present an initial assessment of their physical characteristics based on their HI signatures and radio continuum properties.

ABSTRACT. In a decade, since the landmark discovery in 2015, gravitational wave astronomy has rapidly evolved, with several hundred compact binary merger events having been observed, predominantly involving black holes. The talk will provide key highlights of the gravitational wave transient events, transient searches and the population studies. It will give future projections of gravitational wave astronomy with the network of gravitational wave detectors including the indian LIGO India.

ABSTRACT. Geodetic Very Long Baseline interferometry (VLBI) is capable of measuring the apparent proper motion of the extragalactic radio sources at 8.4 GHz with high accuracy. Using the time series of the radio source positions over 1993-2025 one could estimate the proper motion of the radio sources and the tiny dipole and quadrupole systematic effects. While the individual apparent proper motion reach 1 mas/year, very special mathematical procedures are required to extract the systematic signal.

Kristian and Sachs in 1966 have noted that the quadrupole systematic may be originate by the primordial gravitational waves in the early Universe. We detected the quadrupole terms with magnitude of 1 $\mu$as/year at 10-$\sigma$ level of statistical significance. It is not clear whether this detected systematic is a manifestation of the primordial gravitational waves, or just an artefact of the astrometric instability due to physical processes in the AGNs.

ABSTRACT. The stability criteria of rapid mass transfer and common-envelope evolution are fundamental in binary star evolution. They determine the mass, mass ratio, and orbital distribution of many important systems, such as X-ray binaries, type Ia supernovae, and merging gravitational-wave sources. In the limit of extremely rapid mass transfer, the response of a donor star in an interacting binary becomes asymptotically one of adiabatic expansion. We built the adiabatic mass-loss model and systematically surveyed the thresholds for dynamical timescale mass transfer over the entire span of possible donor star evolutionary states. Many studies indicate that new mass transfer stability thresholds play an essential role in the formation and properties of double compact object populations and the progenitors of SNe Ia and detectable GW sources. For example, our studies show that the mass transfer in the red giant and the asymptotic giant branch stars and the massive stars can be more stable than previously believed. Consequently, detailed binary population synthesis studies, using updated unstable mass transfer criteria, predict that the non-conservative stable mass transfer may dominate the formation channel of double stellar-mass black holes and can explain the population of the large mass ratio double stellar-mass black holes. Using our updated mass transfer thresholds, binary population thesis studies by Li et al. show that Ge et al.'s results support the observational double white dwarfs quite well.

ABSTRACT. A rotating star with non-axisymmetric deformation continuously emits gravitational waves at a fixed frequency. The detection is important to explore the interior of neutron stars. In this paper, we consider the magnitude of the deformation sustained by the elastic force in the crust in an evolutionary scenario. Stellar deformation is assumed to be large due to an energetic state before the solidification in a hot era of the proto neutron star. However, the deformation shrinks with decrease of driving force as the star cools. Without elastic force, the deformation vanishes. The deformation is imprinted on the crust. We discuss how much deformation remains. Our theoretical estimate will be tested in gravitational wave astronomy.

Reference: arXiv:2601.13550 MNRAS(2026) 546 "Relic of quadrupole deformation produced in a hot neutron star era"

ABSTRACT. We propose the use of gravitational waves as a direct probe to break the NS-BH degeneracy as central engine of core-collapse supernovae. This degeneracy may be resolved by GW-calorimetry, given the $\sim 160$Mpc horizon distance to emissions of gravitational energy, $E_{GW}$, of the order of few\% $M_\odot c^2$, within the LIGO bandwidth of $<1$KHz. Here, we report on a deep search for gravitational radiation from the nearby event SN 2023ixf at 6.85\,Mpc. A black hole central engine is expected to reveal itself by a long-duration gravitational-wave chirp powered by BH spin-down. By universality of black holes, this signal is well-defined by mass-scaling of GW170817B powered by the low-mass black hole produced in delayed gravitational collapse following GW170817. Given the proximity of SN 2023ixf, a long-duration GW spin-down signal comparable to that inferred in GW170817B would have been detectable in the available data. The lack of detection of such signal disfavors central engines involving long-lived, rapidly rotating BHs and instead supports scenarios consistent with a NS remnant with the progenitor mass is likely below $\sim 20 M_\odot$.

ABSTRACT. Growing interest in white dwarf-neutron star (WD-NS) mergers has been driven by recent detections of kilonova-like transients associated with long-duration gamma-ray bursts (GRBs), such as GRB 211211A and GRB 230307A. Owing to the relatively lower densities and longer free-fall timescales of WDs, WD-NS mergers have emerged as promising progenitor candidates. Compared to binary neutron star (BNS) and neutron star-black hole (NS-BH) systems, the intrinsically low density and extended structure of WDs impart unique characteristics to WD-NS mergers. In particular, they can trigger substantial early mass transfer and lead to the formation of a massive, extended accretion disk, ultimately producing polar-dominated unbound ejecta outflows, consisting primarily of original WD material and synthesized iron-group elements. Despite these intriguing prospects, multimessenger investigations of WD-NS mergers are still at an early stage and remain comparatively underexplored.

Motivated by this, our works not only investigate the prospects for gravitational-wave (GW) detections of WD-NS mergers, with the help of early warnings from two space-borne decihertz GW observatories, but also explore how the intrinsically non-spherical geometry of WD-NS wind ejecta affects the viewing-angle dependence of their thermal electromagnetic (EM) counterparts. With a sufficient 1-d early-warning time, the expected annual detection rate reaches a few thousand for DO-Optimal and tens of thousands for DECIGO. More importantly, most WD-NS mergers can be localized to within ~ 0.01 deg2. Using a two-dimensional axisymmetric ejecta configuration and incorporating heating from the radioactive decay of 56Ni, we employ a semi-analytical discretization scheme to simulate the observed viewing-angle-dependent photospheric evolution, as well as the resulting spectra and lightcurves. The observed photosphere evolves over time and depends strongly on the viewing angle: off-axis observers can see deeper, hotter inner layers of the ejecta and larger projected photospheric areas compared to on-axis observers. For a fiducial WD-NS merger with an ejecta mass of 0.3 solar mass and a 56Ni mass of 0.01 solar mass, the resulting peak optical absolute magnitudes span from -12 mag along the polar direction to -16 mag along the equatorial direction, corresponding to luminosities of 1e40-1e42 erg s-1, with characteristic timescales of 3-10 d. Lower ejecta and 56Ni masses should yield fainter, more rapidly evolving EM transients.

Our results offer valuable guidance for forthcoming GW detectors and EM follow-up campaigns. Future multimessenger observations hold the potential to shed further light on WD-NS mergers, allowing tighter constraints on their properties and deepening our understanding of these systems.

ABSTRACT. Starting in 2018, observations of galaxy clusters through the world’s best telescopes have revealed unusual phenomena: short-lived fluctuations in brightness, and sometimes position, localized to compact regions within gravitationally lensed images (the bending of light due to mass, predicted by Einstein’s theory of general relativity). Sometimes, these transient events also manifest as the complete appearance or disappearance of lensed images. Despite the increasing number of observed transients, their origin still remains a topic of debate.

Amongst several hypotheses, a leading contender is that the individual stars in the background galaxies are being gravitationally lensed by intervening stars in the foreground galaxy cluster, thus being sufficiently magnified (or demagnified) in brightness to be detected in observations. Here, I will show how the recent JWST observations of more than 40 transient events within a single gravitationally lensed arc, known as the Dragon Arc, can be used to probe the nature of Dark Matter (DM) - a mystery withstanding nearly a century and considered one of the most pressing problems in modern physics. These observations show a preferred spatial clustering inside rather than outside the cluster critical curve (a region where the light magnification reaches the highest values).

We find that the pervasive density modulations predicted by ultra-light DM particles such as Axions can create such an effect, while ultra-massive DM particles predict the opposite effect. This finding follows on the wake of our previous work, featured on the front cover of Nature Astronomy (Amruth et al. 2023), where we demonstrated that the two-decade long flux anomaly problem in galaxy lensing can also be resolved if DM is composed of ultra-light particles, providing independent support and pointing the path towards new physics.

ABSTRACT. High-redshift galaxy clusters show a striking diversity in their star-formation activity, raising the question of what keeps some systems “fresh” while others are already quenched. I will present an observational–theoretical synthesis of how large-scale structure (LSS) and the cosmic web regulate star formation in clusters at z < 1.4. Multiobject spectroscopy of ∼20 overdensities at 0.6 < z < 1.3 first revealed that clusters and groups embedded in extended (~10 Mpc) LSS have significantly lower quiescent-galaxy fractions than more isolated systems, suggesting continuous replenishment by infalling star-forming galaxies (“more connected, more active”). Deep Magellan/IMACS spectroscopy in the UDS field then confirmed two z ∼ 0.95 clusters with similar halo masses (log M200/M⊙ ∼ 14) but strongly contrasting quiescent fractions; their surrounding filaments and infalling populations are again consistent with the LSS–quenching anticorrelation. Extending to a statistical sample of 68 cluster candidates at 0.3 ≤ z ≤ 1.4 in COSMOS2020, we find that clusters with lower quiescent fractions are preferentially connected to more extended LSS, while IllustrisTNG simulations show that group and galaxy infallers remain more star-forming than cluster members and can lower cluster quiescent fractions. I will discuss how these results jointly constrain the cosmic web-feeding picture and outline future prospects with various upcoming surveys.

ABSTRACT. Galaxies’ distribution and their redshift evolution are essential elements in cosmological research. The Analysis of Resolved Remnants of Accreted Galaxies as a Key Instrument for Halo Surveys (ARRAKIHS) is an upcoming European Space Agency mission designed to advance our understanding of the Universe. ARRAKIHS aims to image faint extended halos of nearby galaxies, providing insight into the nature of dark matter. Moreover, the wide field of view and unprecedented flux sensitivity (31 magnitude/square arcsec) of ARRAKIHS give us a unique opportunity to constrain cosmological parameters using dN/dz, the redshift-dependent differential number density of background galaxies. This study utilizes the dataset from COSMOS2020, which is a comprehensive multi-wavelength photometry and photometric and spectroscopic redshift catalog of approximately 1.7 million sources across a 2-square-degree area of the sky. We transform this dataset into the ARRAKIHS framework, using its total throughput for each photometric band. Using machine learning techniques to predict redshifts from transformed photometric data, ARRAKIHS’ potential to provide accurate, reliable measurements of galaxy redshift distributions is assessed. This advancement in measuring galaxy redshift distributions will significantly deepen our understanding of the universe, especially by testing the Λ Cold Dark Matter cosmological model and the role of dark matter in galaxy formation. The preliminary Fisher-matrix forecasts indicate that an ARRAKIHS-like dN/dz analysis can achieve uncertainties of approximately σ(Ωₘ) ≈ 0.05 and σ(w) ≈ 0.3 with σ(z) ≈ 0.07(1+z) at z < 1.0, which translates to 95% confidence intervals of ΔΩₘ ≈ ±0.1 and Δw ≈ ±0.6 even in the pessimistic case. The derived constraints, though a bit coarse compared to the leading cosmic probes and standard candles, provide orthogonal constraints and different systematics on the Ωₘ-w plane, which could significantly improve cosmological constraints and may shed new light on the Hubble tension.

ABSTRACT. Simulation-based inference (SBI) provides a rigorous framework for performing Bayesian analysis using only forward simulations. Its key strength lies in their capability to account for complex physical processes and observational influences within these simulations. In our earlier work (Tam et al. 2022), we demonstrated the promise of likelihood-free forward modeling for cosmological inference by jointly analyzing the redshift evolution of galaxy cluster abundance with weak-lensing mass calibration.

In this talk, I will present our latest application of this statistical framework to the joint XXL-HSC weak-lensing mass calibration of clusters selected from the XMM-XXL survey. I will begin by outlining the fundamentals of SBI and describing our updated forward model, in which key cosmological parameters—such as Ωₘ and σ₈—are directly inferred while marginalizing over astrophysical and observational systematics, including miscentering, lensing mass bias, and photometric redshift uncertainties. I will conclude with our unblinded cosmological constraints and the calibrated mass–observable scaling relation for XXL clusters.

ABSTRACT. Galactic disks experienced a critical phase of rapid evolution 8–10 billion years ago (Cosmic Noon; redshift = 1–3), shaping the morphological types seen in the local Universe. Thanks to JWST, we can now resolve the characteristic substructures like galactic bars, spiral arms, and star-forming clumps. Studying their properties provides a glimpse into the evolutionary state of the host disks. I will present results from a series of works where we have successfully modelled the various substructures and thereby revealed their properties. We find that the large fraction of bars in Cosmic Noon star-forming galaxies feature flat profiles, usually seen in mature quiescent systems in the local Universe. Meanwhile, the abundant massive (0.1 pc–1 kpc) star-forming clumps in these systems are found to have a hierarchical nature similar to star-forming regions of local galaxies, suggesting fundamental similarities. These clumps may also be sheared by the differential rotation of the disk, giving rise to spiral arms. However, some of the spiral arms feature clear density-wave-like characteristics, suggesting the presence of sustained quasi-static global oscillations in disks by z ~ 1. The presence of apparently long-lived well established bars and spirals in Cosmic Noon galaxies challenges the pre-JWST expectations of the galactic disks in this epoch being unable to sustain such features.

ABSTRACT. In recent years, JWST has discovered a new type of astrophysical bodies called Little Red Dots (LRDs), which have been believed to be highly accreting supermassive black holes (SMBHs) in the early universe, perhaps the early phase of Active Galactic Nuclei (AGN) observed at lower redshift. We have previously proposed a two-phase accretion scenario for forming SMBHs with masses around billion solar masses at high redshifts z>~6 (Hu etal., MNRAS, 365:345-351, 2006; doi:10.1111/j.1365-2966.2005.09712.x). We also proposed a model in which a single intrinsic luminosity function can explain the observed apparently different luminosity functions of Type-I and Type-II AGNs, by taking into account the inclination effects of the AGN accretion disk radiation (Zhang, ApJ, 618:L79-L82, 2005; doi:10.1086/427800). Applying the key ingredients of our two models above, the basic properties of LRDs, in particular the recent discovery of two LRDs transitioning into quasars (Fu et al. arXiv:2512.02096), can be consistently understood.

ABSTRACT. Projects to send humans to Mars are underway, including NASA's Artemis program. Therefore, it is conceivable that by the time today's middle and high school students reach adulthood, we may enter an era where humans reside on Mars. To highlight the value of collaborative efforts and generative AI support in space education, we held a workshop where participants created flipbook animations depicting the life of a Mars colonist. We used generative AI to enable middle and high school students who are interested in space but not deeply knowledgeable to create animations in a single day. However, we carefully designed it so that participants can learn, through experience, to use generative AI effectively as a support tool without over-reliance. Therefore, we structured the workshop as group work. As a preparatory step for the workshop, participants bring images that align with their consolidated thoughts, using the information we provided about the Martian environment as a reference. It is because group work cannot be conducted effectively without participants having pre-organized their thoughts. At the beginning of the workshop, we shared the information again and showed an example flipbook animation to help participants imagine the final deliverable. Participants then split into groups. After introductions and explanations of their thoughts using their images, each group discussed and clarified what would be needed to live on Mars. These activities were the first half of the workshop. Subsequently, participants interacted with our developing system, powered by a story-generation algorithm, to complete a narration script for the life story of Mars colonists. During the script creation process, participants used the system's generative AI to draft scripts, which they revised to reflect their group's thoughts. We specifically emphasized that they should not use the AI-generated drafts as-is, but rather revise them to incorporate the group's clarified thoughts from the first half of the workshop. It resulted in significant differences in the tone of the narration scripts produced by each group.　Furthermore, using the completed scripts as a basis, they finished flipbook animations as the final deliverables with AI movie editing software. At the workshop, we held a presentation session at the end where each group showcased the animations they had created as a culmination of their work. The group work involved two groups of three junior high and high school students each, plus one group of four adults as a comparison. We found, through text analysis of the narration scripts using KH Coder, that despite our providing the same information to the groups, the completed animations differed significantly between groups, and the tendencies of the junior high/high school groups differed markedly from those of the adult group. We will introduce the workshop content, animations, system, and analysis results. We believe our presentation will serve as a practical example for the audience on how individuals with limited space knowledge can complete an animation in a single day through a workshop, and as a reference for utilizing generative AI as a supporting tool, demonstrating its educational potential.

ABSTRACT. Children from migrant, low-income, and rural communities in India face substantial barriers to engaging with science. National Education Policy surveys underscore the scale of this challenge, reporting that India has over 33 million out-of-school children and that more than half of Grade 5 students are unable to read Grade 2–level texts. Frequent school disruptions, limited teaching resources, and socio-economic instability further restrict children’s exposure to STEM subjects, particularly astronomy, which, despite the sky being open to all, is rarely introduced through hands-on or inquiry-driven methods. These systemic gaps disproportionately affect the very communities that Khagolvani seeks to serve.

Khagolvani is an astronomy outreach initiative of the Department of SPASE, Indian Institute of Technology Kanpur, supported by the IAU Office of Astronomy for Development (IAU-OAD). It addresses these gaps by designing accessible, contextually grounded astronomy learning experiences for underserved learners. The program adopts a child-centred outreach model built around hands-on activities, night-sky introductions, and simple observational exercises that demystify celestial phenomena through low-cost and locally reproducible materials.

In its first six months, Khagolvani has delivered foundational astronomy activities, developed learning materials, and established partnerships with village schools, migrant settlements, and community learning centres across Kanpur, Uttar Pradesh. To date, the program has reached over 2,000 children through activity-based workshops and stargazing sessions. Core modules cover foundational concepts such as the solar system, celestial motions, lunar phases, eclipses, seasons, and basic optics, all explained through engaging interactive models. They also include hands-on activities such as building simple optical and radio telescopes. These activities encourage children to connect astronomical ideas to the natural world, make observations, record patterns, and ask questions, thereby strengthening scientific curiosity and exploratory thinking.

A parallel teacher-engagement component equips educators with simple demonstrations and adaptable lesson formats suitable for resource-constrained classrooms. A major goal of the program is long-term sustainability by supporting schools and community centres in establishing Astronomy Clubs and providing low-cost activity kits that enable them to run sessions independently. A growing network of university volunteers contributes to facilitation, documentation, and content development, reinforcing both community participation and student leadership in science communication. Further, the development of a portable observatory is also being planned for future phases to extend Khagolvani’s programs to low-resource communities.

ABSTRACT. The IAU South West and Central Asian Regional Office of Astronomy for Development (SWCA ROAD, https://iau-swa-road.aras.am/) was founded in 2015 in frame of the IAU Strategic Plan and Office of Astronomy for Development (OAD) regional network. The Byurakan Astrophysical Observatory (BAO, Armenia) is hosting the office. Armenia, Georgia and Iran and later Kazakhstan, Tajikistan and Turkey agreed for this regional collaboration. SWCA ROAD is active in all three main directions: 1) professional astronomy, 2) astronomy education and 3) public outreach. Among the recent activities one could mention the Regional Astronomical Workshops, Regional Astronomical Summer Schools (RASS, the last one was held in Sep 2025), organization of the joint Armenian-Georgian Colloquium in 2025 (17th in this series), collaboration with the Iranian Astronomical Society (MoU in 2025), recent Scientific (Astro) Tourism developments, collaboration with E-ROAD and Arab World ROAD (MoUs between 2 ROADs, BAO and Sharjah University, BAO and University of Jordan, etc.). Regular videoconferences are being held between the SWCA countries representatives, as well as SWCA ROAD coordinators regularly participate in OAD/ROADs videoconferences and face-to-face meetings, IAU GAs and OAD sessions there, European Annual Meetings, MEARIMs, etc. Due to collaboration between SWCA and Arab World ROADs we initiate a new format of relations between the IAU Regional Offices. In addition to the above mentioned, we combined one of the RASS in 2023 with the 1st Inter-Regional Astronomical Summer School (1IRASS), organized jointly with Arab World Regional Office. We also have signed MoU between BAO and the National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) where (in Beijing) another IAU Regional Office is hosted, the IAU East Asia ROAD. Collaboration with Silk Road project has been made. In Asia, IAU has 4 Regional Offices: South West and Central Asia (SWCA) based in Armenia, Arab World based in Jordan (also partially covering North of Africa), East Asia based in China, and South East Asia based in Thailand. Moreover, we collaborate with the IAU European ROAD, namely in frame of EU Erasmus+ project and may serve as a link between Asia and Europe. Our further plans include involvement of new regional countries, development of the regional VO network both for scientific and educational purposes, development of Astronomy-related inter- and multi- disciplinary sciences and strengthening of the role of the Regional Centre aimed at regional collaboration between all natural sciences. To strengthen the inter-regional collaboration, namely in frame of the IAU Regional Offices, we plan to discuss and promote the building of Asian (and Australian) telescope network (especially given that several big/medium-size telescopes appeared in Asia): China, Indonesia, India, Kazakhstan, Iran, Armenia, Turkey, etc.), collaboration in frame of the Virtual Observatories; building an Asian VO network (in Asia, only 6 countries have VO projects: Japan, China, India, Russia, Kazakhstan and Armenia, and the others need to be involved), joints meetings and schools for young astronomers, development of Astro Tourism in Asia, mutual visits (during the recent years, we have visited China, India, Korea, Indonesia, Iran, UAE, Jordan, Kazakhstan, Uzbekistan, Tajikistan and Georgia), etc.

ABSTRACT. Access to empirical science in fields such as observational astronomy, cosmology, and high energy physics remains highly centralized. Large scale facilities—such as major radio telescopes, gravitational wave observatories, and high energy experimental infrastructures are typically concentrated within elite research institutions. Teaching focused colleges and resource constrained institutions, particularly in developing regions, often lack the infrastructure necessary for meaningful hands-on engagement in observational science. This structural imbalance limits participation in empirical research, restricts local scientific capacity building, and reinforces global inequities in knowledge production. Our initiative emerges from the conviction that science must be inclusive, participatory, and regenerative. Rather than positioning advanced scientific infrastructure as inherently exclusive, we explore how distributed, low cost, and modular instrumentation can create new pathways into observational astronomy. Since 2022, we have designed and implemented an affordable observational framework tailored for undergraduate institutions with limited resources. The system includes modular tools capable of observing solar phenomena, basic galactic radio emissions, and radio-frequency signals, integrated directly into undergraduate curricula to ensure pedagogical continuity rather than stand-alone demonstration use. The model combines three complementary components: (1) low cost, scalable instrumentation; (2) integration with open access archival data; and (3) a distributed learning ecosystem that encourages collaboration and local ownership. Students participate actively in instrument calibration, data acquisition, signal processing, and interpretation. This transforms the classroom from a passive learning space into an inquiry driven environment that simulates authentic research workflows. Faculty observations and preliminary indicators suggest increased student curiosity, improved conceptual understanding of observational methods, and greater ownership of scientific inquiry. Student led mini projects have emerged organically, demonstrating that meaningful engagement in empirical science is possible even in the absence of centralized mega facilities.

ABSTRACT. There are several types of astro-tourism activities, which have been widely enjoyed by astronomy enthusiasts all over the world, such as stargazing, starbathing, eclipse watching etc. In 2025 we develop a new type of activity which combines marine and celestial tourism, namely, starfishing. This activity has the potential to provide a tourism comparative advantage for an archipelagic region with high fraction of clear sky and low light pollution. The aim of starfishing is providing experience to tourists about the way ancient fishers go fishing at night using the stars as the navigation guide. The first experiment to evaluate this concept was performed at Menia beach, Sabu Island. The site was chosen because it has been recorded to have the highest fraction of clear sky in Indonesia. The island also has low light pollution due to low economic level, therefore starfishing is expected to contribute significantly to the economy of the island if it becomes a regular tourism activity in the future. From the experiment we formulated a set of guidance for performing starfishing. The concept was then introduced to a marine tourism village, Jasri, on Bali Island, as an experiment in a more realistic tourism environment and service provider. We concluded that longer coaching is needed to get them ready to provide starfishing services. The concept will be applied to other selected tourism villages in the dry regions of Indonesia

ABSTRACT. The Sky Explorers Festival, organized annually by SINA since 2013 in Iran, is a unique educational initiative that blends environmental engagement with experiential astronomy learning. Developed to inspire curiosity about the universe while strengthening students’ connection with nature, the festival brings participants together in small, collaborative groups for a full day and night of immersive outdoor activities. This structure not only enriches their scientific understanding but also supports personal growth and social development.

The program begins in the afternoon as students arrive at the natural site and familiarize themselves with the environment. Before sunset, participants construct simple, hand-made astronomical tools—such as star wheels or basic angle-measuring devices—which they later use during guided nighttime observations. Creating these tools themselves promotes creativity, problem-solving, and a practical grasp of core astronomical concepts.

After nightfall, the festival shifts to its central educational component. Students are introduced to observational astronomy, including constellation identification, celestial motion, and the cultural and scientific relevance of the night sky. Under the guidance of trained instructors, they observe planets, nebulae, star clusters, and other deep-sky objects using telescopes. These direct observational experiences reinforce theoretical knowledge while cultivating a sense of wonder and an appreciation for natural darkness, increasingly endangered by global light pollution.

Complementing the scientific components, the festival includes group games, cooperative tasks, and overnight camping. These activities foster teamwork, communication, resilience, and social interaction, allowing students to develop key interpersonal skills in a supportive outdoor environment. Spending the night in nature also deepens their environmental awareness and highlights the ecological dimension of astronomy.

In recent years, the success of the Sky Explorers Festival has led to the development of a comprehensive festival proposal that is now available to countries around the world seeking to implement a similar experience. This international framework enables other organizations and educational institutions to adopt, adapt, and localize the program, expanding its impact and encouraging global engagement with astronomy and nature-based learning.

Overall, the Sky Explorers Festival aims to offer a holistic learning journey that unites science, nature, and social development. By integrating hands-on observation with environmental immersion, the festival helps students appreciate the value of the night sky, understand its relationship with natural ecosystems, and develop essential scientific and social skills that extend far beyond the event itself.

ABSTRACT. The threat of the Kessler syndrome is very real and increasing just as the ramping upof LEO launches accelerates and the plans for massive satellite constellations gather pace. There is a serious disconnect between plans and threats to the very ecosystem into which vast asset numbers are foreseen in the next decade where the current modelling predicts the Kessler syndrome of cascading catastrophic collapse of the entire LEO ecosystem comes to pass. Something has to change and soon. In this presentation we will present the "S3+1" concept of the orbital Space commons as Space for Safety, Science and Sustainability via a HKSAR based NGO. It would need Mainland and HKSAR top level endorsement from the get-go. It would be connected to but from, the proposed new and urgently required HKSAR Space Office. It would act as an umbrella organisation for accessing talent, resources, international partners and top-level global connectivity. It would utilise homegrown and international talent. It would host a top level centre of orbital satellite and debris data for sharing with the world for STM imperatives. It would overall be impactful, influential and reputationally strong and based solidly on the strong structural cards HKSAR holds in finance, compliance and arbitration, insurance, investment, regulation and globally elite universities all within a respected common law jurisdiction and global super-connector city.

ABSTRACT. This research taked the upper stage of the CZ4C rocket as the research object, and developed a set of photometric modeling and attitude inversion methods for space debris attitude analysis, which were applied to the attitude determination of telescope-observed light curves. The study takes the 2022-027B target as the main research object, and obtains the light curves of the target during its orbital flight through optical telescopes. We use genetic algorithm to solve the attitude parameters and systematically study the relationship between the attitude parameters and the fitness of the genetic algorithm. Through the joint analysis of 1-day, 3-day and 30-day observation data, we found that the relationship between the average attitude parameters and fitness exhibits time-independence, which allows us to integrate all the photometric data to constrain the attitude parameter range. Random sampling verification shows that the simulated light curves are well consistent with the observed data. The method was further applied to the CZ4C target launched at different periods (21 years, 10 years, and 1 year after launch). The results showed that the relationship between their attitude parameters and fitness remained basically stable, indicating that the targets could maintain a stable rotation state under the solved attitude parameters during this period. This finding provides a new research approach for studying the long-term attitude evolution of space debris.

ABSTRACT. With the advancement of space activities, the safe disposal of navigation satellites that have completed their mission tasks has become increasingly critical. The safe disposal of these satellites not only involves the efficient utilization of orbital resources but also directly impacts the control of space debris and collision risks. Based on studies of orbital evolution of objects near GNSS orbits, analyzing the long-term dynamical characteristics of these orbits to identify suitable ones for end-of-mission satellites to maintain a safe state and reduce collision risks with other space objects is an urgent issue that needs to be addressed. Coordination of disposal strategies becomes a common task and a general problem.

The disposal strategy based on the use of long-period eccentricity perturbations to ensure guaranteed re-entry has a drawback. For MEO, even for an object with a high area-to-mass ratio, it takes several decades for re-entry. In doing so, the satellite will repeatedly pass through areas where active satellites are operating. We mean all satellites, not just navigation satellites. We propose that satellites after end-of-mission should be placed above the operational orbits of the system. The requirement for disposal orbits is that the satellite should not enter the area of active satellites at intervals of 100-200 years. We hope that during this time effective systems of active space debris removal will be developed.

We consider the problem of selecting orbits for the deployment of end-of-life global navigation system satellites. The orbital evolution of objects is modeled numerically over 200 years for near GNSS region in MEO and 175 years for near BeiDou-IGSO area.

Our study focuses on analyzing the long-term evolution of eccentricity due to luni-solar secular perturbations and solar radiation pressure. We varied longitude of the ascending node of the orbit and the satellite area-to-mass ratio. Since the long-term evolution of eccentricity depends on the initial orientation of the orbital plane relative to the direction to the Sun, we chose orbits with minimal eccentricity variation as disposal orbits. Such orbits correspond to long-term evolution outside of inclined luni-solar resonances. On the other hand, the influence of secondary secular apsidal-nodal resonance caused by solar radiation pressure in the zone of inclined luni-solar resonance at certain area-to-mass ratio values leads to a significant reduction in the amplitude of eccentricity oscillations. These regions may have a higher density of space debris compared to neighboring regions, where orbits may have higher eccentricity values.

We propose placing the satellites in orbits from 100 to 500 km higher on the semi-major axis with respect to corresponding operational orbits in MEO region and from 250 to 500 km above IGSO. By suitable positioning of the orbital plane with respect to the direction to the Sun, it is possible to achieve a minimal change in eccentricity over a long-time interval of up to 100 years and more for area-to-mass ratios less than 1 m2/kg.

ABSTRACT. The rapid growth of active satellites and space debris, driven by cheaper launches has increased the need for frequent, accurate orbit updates for collision avoidance. In the context of space sustainability, ground-based optical telescope networks provide routine monitoring, but a key challenge remains manual identification of satellite streaks and their association across frames into tracklets.

We present a deep-learning method to automatically classify regions of interest (ROIs) extracted from reduced telescope images as either moving-object tracklets or stars. Using 185,000 labelled ROIs, we benchmark several models and show that data augmentation is critical for robust performance. The best configuration reaches 99.99% classification accuracy when trained directly on raw CCD pixel values.

This approach is intended for integration into an existing tracking software deployed on multiple telescopes, enabling real-time astrometric updates to support the growing demands of modern SST operations.

ABSTRACT. Over the past decade, the rapid expansion of satellite mega-constellations has severely disrupted ground-based optical astronomy, while together with space debris, it has posed a dual challenge to space security. Large field-of-view telescopes, capable of covering extensive sky areas in a single observation, are highly valuable for detecting moving space targets. Yet, their utility is constrained by complex observational backgrounds and the presence of multiple objects moving at varying speeds and directions, which complicates the reliable detection and tracking of space objects. Addressing these challenges is crucial for maximizing telescope performance, mitigating satellite constellations interference, and strengthening space situational awareness. This study presents a method for detecting and tracking multiple space objects with diverse motion patterns against complex backgrounds. The method first extracts multidimensional features of the targets, then employs a star registration and clustering approach to automatically annotate targets and stars. After balancing the data, an artificial neural network model is constructed and trained to accurately classify point-like targets and stellar streaks. Combining the model's classification results, further techniques of trajectory association and morphological statistical analysis are adopted to effectively detect tracked targets and other moving patterns. Finally, an improved DeepSORT method is utilized for real-time tracking of multiple moving targets. Experimental results on simulated images show that the method achieves a multi-target tracking accuracy of 94.96% and an IDF1 score of 96.22%. Experimental results based on observational images from the 1-meter large field-of-view telescope demonstrate that this method achieves a multi-target tracking accuracy of 90.89% and an IDF1 score of 89.66%. This method is highly flexible and adaptable, significantly reducing the demand for training data volume. Even under typical interference scenarios such as intersecting target trajectories or the temporary disappearance of faint targets over multiple frames, it can achieve accurate identification and stable tracking of both low-Earth orbit and high-altitude space objects.

ABSTRACT. The rapid expansion of satellite constellations is fundamentally transforming the orbital environment, creating new and increasingly complex challenges for the protection of dark and quiet skies. Astronomy, which has historically driven major scientific and technological advances—from our understanding of the Universe to practical applications such as navigation, medical imaging, and communications—is now facing sustained impacts from both optical and radio interference.

This presentation outlines the principal mechanisms through which satellite systems affect astronomical observations, including sunlight reflection producing optical streaks, downlink radio emissions, and unintended electromagnetic radiation (UEMR) from onboard electronics. These impacts are no longer isolated events but are becoming a steady-state condition as the number of satellites continues to grow rapidly. Emerging space-based applications, such as direct-to-device communications and orbital data centers, may further exacerbate these effects.

A range of technical mitigation measures is being developed by both satellite operators and the astronomical community, including reduced reflectivity, improved emission control, operational coordination, and advanced data processing techniques. However, these solutions remain largely voluntary, unevenly implemented, and insufficient on their own.

The presentation explores the ongoing efforts across multiple domains, including international frameworks such as the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) and the International Telecommunication Union (ITU-R), as well as national regulations and emerging standardisation initiatives. It emphasises the need to move from awareness to coordinated global action, combining technical, regulatory, and collaborative approaches to ensure the long-term sustainability of the space environment and the preservation of the Dark and Quiet Skies for science and society.

ABSTRACT. A workshop convened by the Secure World Foundation and related academic initiatives defined space sustainability through three core elements: peace and security, environmental conditions, and socio-economic equity. Notably, this framework did not include indigenous culture, despite extensive scholarly work demonstrating the profound connection between ancient civilizations and celestial knowledge. In the contemporary context, this connection is exemplified by astrotourism, a niche tourism sector centered on night-sky experiences—such as stargazing and eclipse viewing—that often aims to foster socio-economic development and environmental conservation. This presentation investigates the potential linkage between astrotourism and the preservation of indigenous astronomical knowledge within Indonesia. As Indonesia is developing a new observatory and considers designating its surrounding area as an astrotourism site, this presentation aims to inform the ongoing policy discussion. Employing a qualitative methodology, this presentation conducted benchmarks against successful models in South Africa and Namibia, where astrotourism has effectively helped sustain indigenous knowledge systems. The analysis was guided by a tourism sustainability theory, which examines the interrelations between tourists, the environment, and capital, and is further contextualized using the United Nations Declaration on the Rights of Indigenous Peoples. The findings indicate that astrotourism can simultaneously advance the goals of space sustainability and safeguard indigenous knowledge. Based on this conclusion, the presentation formulates practical policy recommendations for the Indonesian government to integrate these dual objectives into its developing astrotourism strategy.

ABSTRACT. With the recent rapid development of satellite constellations, we face an increasingly challenging radio spectrum environment for observations. From both known communication frequencies regulated by the International Telecommunication Union (ITU) and incidental electromagnetic radiation and leakage.

Although satellite ephemerides are generally known, the growing complexity of constellation operations and telescope arrays spread across large areas such as the SKA introduces a multiplexed problem for maintaining a clean spectral environment during observations. In this paper, we present a comprehensive simulation framework designed to quantify the impact of satellite constellations on large interferometric arrays. Our multi-layered approach dynamically models satellite emission projections and provides an all-sky, all-direction, high time–resolution antenna response for observations. We then demonstrate how these simulations can be combined with satellite measurements to predict impact on interferometry. We also present application examples to improve observation planning and scheduling in an increasingly crowded radio spectrum using these simulation results.

ABSTRACT. The number of objects in orbit is rising dramatically. Identifying potential hazards in the space environment – such as space debris – is an increasingly vital and difficult task, necessary to ensure safe and sustainable activities in space as well as to preserve the night sky for astronomical research. While objects in orbit can interfere with astronomical research, there is also an under-developed opportunity in the field of astronomy to contribute to efforts to detect, characterise, identify and track these Resident Space Objects (RSOs). RSOs, including satellites and space debris, can leave streaks when passing through the fields of view of telescopes conducting astronomical surveys. Astronomers have a unique opportunity to detect RSOs by repurposing the vast volumes of data collected nightly through current and future all-sky surveys. This will open an avenue to an under-explored source of wide-field space situational awareness (SSA) data, providing a complementary use case for data already being generated as part of regular surveys. The Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST) will scan the entire southern sky every 3 days. Data collected for LSST will be rapidly processed and distributed via international data brokers, with products being available to the community just minutes after being collected. It is expected that over 10 million transient alerts will be generated each night within this survey, including detections of known and unknown RSOs. This work prepares for LSST using unique, fast-cadenced, wide-field data from the Deeper, Wider, Faster (DWF) astronomical survey. This optical data is collected via the Dark Energy Camera (DECam) on the Victor M. Blanco 4-metre Telescope in Chile. The 4-metre aperture of this telescope will allow us to detect faint objects down to sub-10cm at geostationary orbits, pushing debris monitoring capabilities compared to traditional ground-based SSA methods. Here we present a 1500-image pilot study into the RSOs that have been observed in DWF data, including 46 known and 22 unknown RSOs, as well as current rates and implications expected with LSST data.

ABSTRACT. This study investigates the photometric dynamics of the twilight bridge—the transition between day and night—utilizing extensive datasets from the Globe at Night Monitoring Network (GaN-MN). While the progression of solar depression angles traditionally dictates twilight phases, anthropogenic interference increasingly skews these natural markers. By constructing high-resolution density plots of sky brightness measurements, this research visualizes the statistical distribution of luminance across thousands of observation points globally.

The analysis reveals two critical departures from natural models. First, significant light pollution effectively compresses the duration of true astronomical darkness, altering the functional timing of twilight by elevating the brightness floor. This shift suggests that in urban environments, the biological and observational transitions associated with twilight are prematurely truncated. Second, the data confirms an empirical pattern of cloud brightening, or the urban graveyard effect, where low-altitude cloud cover amplifies artificial skyglow through enhanced backscattering.

These findings provide a quantitative framework for understanding how the nocturnal landscape is being eroded. The resulting density maps or scotograms serve as a diagnostic tool for atmospheric scientists and urban planners to assess the ecological and astronomical impact of artificial light at night (ALAN) during the sensitive twilight period.

ABSTRACT. Hanle is one of India’s most pristine astronomical sites(Indian Astronomical Observatory a field station of the Indian Institute of Astrophysics ), with a growing cast of telescopes that scan the night skies at different wavelengths. Located on the Tibetan Plateau, Hanle is also home to a unique wetland ecosystem and to pastoralists with a long cultural history. In recognition of this scientific, ecological, and cultural importance, the Hanle Dark Sky Reserve (HDSR) was established in 2022 to protect its night skies, offer sustainable economic opportunities, and emphasize local heritage. With HDSR as a case study, this talk examines the emerging challenges to our continued relationship with darkness, night skies, and the cosmos. Firstly, the increasing terrestrial light pollution due to expanding astrotourism, infrastructure development, and strategic installations. Secondly, the changing climatic trends that are reducing photometric nights and long-term observing efficiency. Finally, the rapid and largely unregulated proliferation of Low-Earth Orbit (LEO) satellites, which is contaminating observational data. Collectively, these three factors are counteracting our efforts to preserve premier dark-sky sites such as Hanle. Besides their impact on ground-based astronomy, the changing night sky and erosion of darkness is accelerating ecological and cultural loss, including traditional uses of stars for timekeeping and migration. This talk argues for a holistic space sustainability framework that links responsible astro-tourism, dark-sky–friendly energy and lighting practices, climate mitigation, documentation of cultural astronomy and deep community participation, and international coordination on satellite governance. The Hanle experience underscores the critical role of public science engagement in bringing together communities, policymakers, and the scientists to better understand and mitigate anthropogenic interference. Such long-term and comprehensive efforts are critical not just for the future of ground-based astronomy, but also for safeguarding cultural continuity, ecological integrity, and humanity’s shared relationship with the night sky.

ABSTRACT. The growing population of satellites and space debris in Earth's orbit is causing increasing interference with astronomical observations. In optical data, these objects leave streak-like features whose brightness depends mainly on size and orbital altitude. Astronomers do their best to mitigate this interference by dodging satellites or by removing contamination during post-processing.

However, the satellite streaks also contain valuable data that can be used to characterise the observed objects. To extract this information, we have developed ODLA (Orbital Debris Lightcurve Analysis), a pipeline to extract precise photometric measurements from satellite streaks in astronomical images. The pipeline correlates detected streaks with catalogued objects, performs radiometric and astrometric calibration of raw images if necessary, and utilizes aperture photometry to obtain lightcurves from the streaks. Where available, field stars contained in the GAIA DR3 or SDSS DR16 photometric catalogs are used for differential photometry to obtain precise magnitudes.

ODLA is currently applied to steaks detected in the image archive acquired with OmegaCAM on the VLT Survey Telescope (VST) at the ESO observatory of Cerro Paranal, which contains hundreds of thousands of images acquired over the last 14 years. We will present examples of extracted lightcurves and how they can be used to determine the rotational period of the observed objects. The lightcurves will be published in our Orbital Debris Lightcurve Inventory (ODLI), a publicly available repository such that they can be used by the space debris research community for further studies. The average magnitude from each lightcurve is further submitted to the Satellite Constellation Observation Repository (SCORE) database that is maintained by the IAU Centre for the Protection of the Dark and Quiet Sky from Satellite Constellation Interference (CPS) in order to support the astronomy community with valuable information required for satellite brightness modeling to better assess the impact of satellite interference with astronomical observations and to evaluate brightness mitigation strategies in satellite design and operation.

Although ODLA was developed specifically for processing ESO/VST OmegaCAM data, it can also be used with data from other telescopes, such as images acquired with the Dark Energy Camera (DECam) on the Blanco 4m telescope located at the Cerro Tololo Inter-American Observatory. The lightcurves published in ODLI provide the basis for further characterization to obtain important information that is required for example for the planning of Active Space Debris Removal (ADR) or On-Orbit Servicing (OOS) missions. Such missions will be necessary to secure long-term access to low Earth orbit in particular and to promote the sustainability of space activities.

ABSTRACT. We face a profound paradox: the very technology created to explore the cosmos is beginning to obscure it. The 2019 launch of SpaceX’s first 60 Starlink satellites starkly revealed the threat that sprawling “megaconstellations” pose to astronomy. While promising global connectivity, these bright, numerous satellites threaten to drown out the night sky, jeopardizing ground- and space-based observations. This article details the challenges for observatories, outlines current mitigation efforts, and introduces the role of the IAU Centre for the Protection of the Dark and Quiet Sky in forging solutions. We describe the efforts of the IAU-CPS with a focus on SATHUB.

Hasan, P. Dark Skies and Bright Satellites. Reson 28, 547–565 (2023). https://doi.org/10.1007/s12045-023-1582-8

ABSTRACT. Currently, about 20 asteroids have been discovered to be in mean motion resonance with Venus (i.e., co-orbitals of Venus) using Earth-based observations [1] while JPL database lists about 69 in a transient state. The research [2] showed that most of the population remains unseen, and thus some members of this population with eccentricities greater than 0.38 could pose a danger to Earth. Therefore, their discovery and classification are one of the important tasks for future work by astronomers and the space community [2].

In this study, an approach to using Venus gravity assists to enable exploration of asteroids in the inner part of the Solar System is proposed. The proposed framework integrates resonant orbit dynamics with Venus gravity assists to enable periodic flybys of asteroids. By transitioning a spacecraft into a 1:1 resonant orbit with Venus (approximate period of 224.7 days), this approach shortens trajectory arcs for transfers to asteroids while maintaining proximity to Venus, enabling repeated scientific observations. The advantage lies in the fact that these orbits allow encounters with co-orbital asteroids on the orbit of Venus, which may have been undiscovered up to this point.

The analyzed mission architecture comprises: • Section 1: Earth → Venus • Section 2: Sequential Venus-asteroid flybys • Section 3: Earth return

These architectures are evaluated using JPL ephemerides for 69 asteroids which have a period that is almost the same as the Venus orbit. The scheme construction also includes flybys of non-resonant asteroids. The analyzed period is for launch windows in 2029, 2031, and 2033-2034. Trajectory validation for these launches aligns with the upcoming Venus exploration initiatives, such as Venera-D. An initial search for encounters is performed using a patched conic approximation model. Trajectories are then refined using numerical calculations and end-to-end optimization.

The results indicate that the design of flybys around asteroids in mean motion resonance with Venus should include interspersing these with flights to non-resonant asteroids. Due to the fact that spacecraft in a quasi-resonant orbit achieved through gravity assists are not fully locked into mean motion and therefore, to maintain its quasi-resonant state, the spacecraft needs to transition between orbits each time it approaches Venus.

As an example, a flight scheme for close study asteroid 2001 CK32 has been developed, which includes flybys of that asteroid and other asteroids that closely approach Venus. In this plan, three flybys with this asteroid have been planned, and six flybys including other asteroids have been planned. It has been found that for a plan involving six asteroid flybys, the overall change in velocity (delta-v) required falls within the range of 3.9–4.2 km/s, comprising 3.77 km/s for the launch and the remainder for maneuvers.

This study was supported by the grant RSF # 25-79-00042.

[1] Carruba, V., Moreira Morais, M. H., Mourão, D. C., et al. 2024, Research Notes of the American Astronomical Society, 8, 213 [2] Carruba, V., et al. "The invisible threat-Assessing the collisional hazard posed by undiscovered Venus co-orbital asteroids." Astronomy & Astrophysics 699 (2025): A86.

ABSTRACT. This study investigates the design of low-energy trajectories that redirect near-Earth asteroids onto heliocentric orbits in 1:1 resonance with the Earth via a gravity-assist at Earth, and then exploit the ensuing geometry to search for subsequent lunar flybys. Such resonant transfers enlarge the set of favorable launch opportunities for direct exploration, in-situ resource utilization, and planetary-defense applications, in which a small redirected asteroid may later serve as an interceptor for a hazardous object.

The initial catalog of candidates filtered using geometric and dynamical criterions. The geometric filter imposes a threshold on the minimum orbit intersection distance with the Earth ≤ 0.05 AU. The dynamical resonant reachability criterion is defined by (1) a small characteristic velocity Δv to reach an orbit with period close to one Earth year; (2) only a minor offset of the semi-major axis from that of the Earth; (3) moderate eccentricity and inclination compatible with feasible rendezvous operations.

For the Aten, Apollo, Amor and Atira asteroid groups, the corresponding distributions are analyzed and maps are generated for several mission-relevant metrics: (1) the Δv of the upper stage required to depart from a 200 km circular low-Earth orbit; (2) the rendezvous Δv at the asteroid.

Five representative targets are identified for which viable departure windows exist: the upper-stage Δv does not exceed 3.6 km/s and the rendezvous Δv is below 0.7 km/s.

After rendezvous, a phasing impulse is applied at the selected asteroid to target an Earth flyby. TThe objective of this gravity assist is to keep the magnitude of the heliocentric velocity nearly constant while rotating its direction so that the post-encounter orbit achieves the desired resonant period. By targeting a period of one year, the asteroid repeatedly returns to the vicinity of the Earth, guaranteeing a sequence of further gravity-assist opportunities. In this regime, combined Earth–Moon encounters effectively act as a “double” gravity assist: the asteroid’s velocity relative to Earth is reduced while its heliocentric orbital energy remains almost unchanged. For asteroid 2000 SG344, the required impulse is 89 m/s.

The post-gravity-assist motion is propagated in a Sun–Earth–Moon ephemeris model. Resonant Earth encounters and passages through lunar-access windows are automatically detected to assess the feasibility of a subsequent cascade of lunar gravity assists. The first crossing of the lunar sphere of influence already opens scenarios for additional deceleration or capture with modest energy cost, provided that the earlier phases of the trajectory are further refined.

This study was supported by the grant RSF # 25-79-00042.

[1] Eismont, N. A., et al. "On the Possibility of the Guidance of Small Asteroids to Dangerous Celestial Bodies Using the Gravity Assist Maneuver" Solar System Research, 2013, Vol. 47, No. 4. [2] Ledkov, A.A., et al. "A method for capturing asteroids into earth satellite orbits" Astronomy Letters, 2015, Vol. 41.