Randa Asad (American University of Sharjah)

Title: Chemical Enrichment History of the Large Magellanic Cloud Galaxy

Abstract: Star clusters represent snapshots of the chemical evolution of their host galaxy at different ages. In the era of large ground-based telescopes, their integrated light can be observed for very distant galaxies. However, it is crucial to validate new techniques against nearby systems for which the results can be independently constrained via resolved stellar population studies.

This presentation discusses our ongoing work on applying both resolved and unresolved spectroscopy methods to a large high-quality sample in the Large Magellan Clouds clusters to infer detailed information about the chemical history of the galaxy. Our results match the theoretical models of the chemical enrichment history well. Motivated by these results, we develop and present a new automated tool publicly available to use for future integrated spectra observations of star clusters in galaxies as distant as 10 Mpc. This will offer new opportunities to study those galaxies at the level of detail that is currently available only in a handful of nearby Milky Way satellites.

Yijia Li (Northwestern)

Title: TBD

Abstract: TBD

Chang-Goo Kim (Princeton University)

Title: TBD

Abstract: TBD

Grace Krahm (Ohio State University)

Title: TBD

Abstract: TBD

Yilun Ma (Princeton University)

Title: From Deep Fields to the Wide Sky: Tracing Little Red Dots Across Cosmic Time
 

Abstract:  Little red dots  are an abundant population of red, compact, broad-line objects discovered by JWST at z=5-8. No existing models can fully explain their SEDs, which are V-shaped in the UV-optical and not strongly detected at other wavelengths. In this talk, I will first briefly review the challenges in understanding the SED of LRDs with JWST. I will then discuss our extensive effort to understand the demographics of LRDs across cosmic time as they are 100x more abundant than quasars at z>5 but rarely identified at cosmic noon. 

I will present our search for LRDs at 2<z<5 using wide-area, ground-based, multi-wavelength imaging surveys, spectroscopic follow-up campaigns and JWST observations. I will discuss our result from this search, including a dramatic number density decline towards lower redshift and a steep cutoff in luminosity functions of LRDs, as well as their implications to the LRD population and more broadly black hole growth. Finally, I will mention our planned multi-wavelength follow-ups of the low-redshift LRDs in the future to understand the nature of these intriguing sources.

Dr. Akash Gupta, Princeton University

Title: Connecting the Dots: From Electrons to Planets

Abstract: The most common planets observed to date fall between the sizes of Earth and Neptune. I will present how my work, together with recent studies, demonstrates that most of these planets accreted hydrogen-helium envelopes from their protoplanetary disks. Over millions to billions of years, some lose these primordial atmospheres through escape processes and emerge as rocky super-Earths, while those that retain their envelopes correspond to the population observed today as sub-Neptunes.

This evolutionary pathway has profound implications for interpreting the diversity of atmospheres now being revealed by the James Webb Space Telescope and for designing future surveys. In particular, these hydrogen-helium-dominated atmospheres are expected to interact strongly with their molten or supercritical interiors over much of their lifetime. Yet, despite their central role in planetary evolution, our fundamental understanding of these atmosphere-interior interactions remains limited, largely because they occur under extreme pressures and temperatures that are difficult to access experimentally.

I will present new quantum-mechanical insights into how key planetary materials — hydrogen, helium, water, silicates and iron — interact and transform under conditions relevant to Earth-to- Neptune-mass planets. I will discuss how these results challenge long-held views on the evolution and structure of planets and outline their implications for interpreting current and future observations, including those from JWST, as well as upcoming missions and facilities such as the Uranian Orbiter and Probe, the Habitable Worlds Observatory and ELTs.

Title: TBA

Abstract: TBA

John Wu, Space Telescope Science Institute

Title: Astronomy Re-envisioned: Investigating the Physics of Galaxy Evolution with Machine Learning

Abstract: Interpretable machine learning (ML) techniques and artificial intelligence (AI) are revolutionizing our ability to study galaxy evolution and large-scale structure. Convolutional neural networks (CNNs) can now reliably predict galaxies' physical properties, including cold gas content and metallicity, directly from three-color optical images. 

These models can even reconstruct entire optical spectra from imaging alone. Highly optimized CNNs can also robustly identify nearby dwarf galaxies from wide-area surveys, expanding the sample of known low-redshift satellite systems by over 10-fold. Meanwhile, graph neural networks (GNNs) can encode simulated galaxies amid their surroundings, learning how the galaxy–halo connection varies with large-scale environment. These applications demonstrate how explainable ML models with strong inductive biases enables new scientific insights in galaxy evolution and cosmology. 

In the era of wide-area galaxy surveys by the Vera C. Rubin Observatory, Nancy Grace Roman Space Telescope and Euclid, advanced ML and interpretable AI methods will play an increasingly prominent role in extracting physical understanding from astronomical datasets.

Title: Star formation and evolution in AGN disks, with application to Little Red Dots

Abstract: Study of stellar objects embedded in AGN accretion disks has been motivated by i) the disk(s) of stars that possibly formed in-situ in the galactic center; ii) the super-solar metallicity of classical quasars independent of redshift, as well as possible AGN+star origin of Little Red Dots; iii) quasi-periodic eruptions connected to star-disk collisions; and iv) LIGO-Virgo gravitational wave sources potentially born in gas rich environments. 

In this talk, I will introduce some recent progress on radiation hydrodynamic simulations of stellar evolution in AGN disks, focusing on their formation from fragmentation of a gravitationally unstable disk and their accretion process in a stratified gas-rich background. We argue that a population of such stars is able to power the extended, optically thick and marginally gravitationally stable disk to generate a big red bump of universal Teff~5000K in the disk SED, which can be invoked to explain continuum features of Little Red Dots.

Title: A novel view of the Milky Way disk and outer Solar system

Abstract: Combining big survey data with advanced statistical analysis is a fruitful approach to new discoveries. I will present two examples.   (1) One is a new mapping technique to provide for the first time a clear and flat view of the phase space of Milky Way disk. Applying it to Gaia data, we found sharp new structures with order-of-unity contrast in number density and metallicity. It opens a new window to study galactic dynamics, calling for theoretical explanation and observational search for similar structures in other disk galaxies.  (2) Another example is a new algorithm searching for moving objects from imaging survey. Applying it to cosmological surveys, I found a dwarf planet with the widest orbit in the Solar system, which places an interesting challenge to the Planet Nine / Planet X hypothesis.