Summer Student Talks

Andrew Robertson

Thursday, June 25, 2026 - 11:00am

Mapping the Universe with the Nancy Grace Roman Space Telescope

The Nancy Grace Roman Space Telescope is a major NASA observatory scheduled to launch on August 30 - just two months from now! With a field of view roughly 100 times larger than that of the Hubble Space Telescope, Roman will survey large areas of the sky while retaining Hubble-like image quality. Its observations will address a wide range of questions, from the nature of planets around other stars to the evolution of galaxies and the expansion history of the Universe.

In this talk, I will give an overview of Roman and then focus on its Galaxy Redshift Survey, which will measure the positions of and distances to millions of galaxies. Together, these galaxies will provide a three-dimensional map of the Universe spanning billions of years of cosmic history. I will explain how astronomers can use this map to study the growth of cosmic structure and test possible explanations for the accelerating expansion of the Universe. I will also discuss some of the practical challenges involved in preparing for the survey, including creating realistic simulated universes that we can “observe” with a virtual Roman telescope. These mock observations provide a controlled test: we generate a universe using a particular model of dark energy, observe it as Roman would, and then see whether our analysis recovers the model we put in.

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Geoffrey Mo

Thursday, July 2, 2026 - 11:00am

Cerberus: a new high-speed imager for the 200-inch Hale telescope's prime focus

Binary systems, especially those involving compact objects, often exhibit behavior on short timescales of minutes or less. While sometimes this activity can be discovered through wide-field surveys, detailed characterization requires high-speed imagers on large telescopes. We are building Cerberus, a new high-speed prime focus imager for the Hale telescope at Palomar Observatory. It will offer simultaneous three-band imaging in u, g, and r/i/z filters, as well as narrow-band capabilities. Taking advantage of recent development driven by consumer technology, Cerberus uses CMOS detectors which have extremely low read noise (0.3 e-) and very high frame rates. We have conducted on-sky testing of the detectors, with system first light slated for 2027.

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Kiersten Boley

Thursday, July 9, 2026 - 11:00am

Elemental Abundances Influence Planet Formation and Rocky Planet Evolution

Planet formation is fundamentally linked to the chemical evolution of the galaxy. For planet formation to occur, there must first be sufficient material within the protoplanetary disk. The growing number of planet discoveries have revealed distinct planet populations (e.g., lava worlds, water worlds, etc.). These populations suggest a diversity of compositions and formation mechanisms that arise from variations in the initial conditions. As more data from spectroscopic surveys becomes available, we can constrain the materials from which planets form and how that impacts their long-term evolution. In this talk, I will show how changes in the planet birth environment controls when and where planets form in the Milky Way and what that tells us about their likely formation mechanism.  I will also present the first evidence for a strong dependence of super-Earth formation on iron abundance. Using the material properties inferred from their birth environment, I will lastly describe how planet composition impacts the long-term evolution of rocky planets through the lens of mineral physics. 

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Grace Olivier

Thursday, July 16, 2026 - 11:00am

Exploring the Production of High-Energy Photons with Galaxies from Local Analogues to Cosmic Noon

One of the main goals of JWST is to see the earliest galaxies in the universe and determine what stars or black holes they produced to ionize the universe during the Epoch of Reionization. Unfortunately, the observational and theoretical toolbox cannot discern between accretion onto black holes or hot massive stars as the source of ionizing photons for the galaxies we are observing during cosmic reionization. The key to understanding the physical processes responsible for reionizing the universe are both the nearby galaxies that are analogues to galaxies during the Epoch of Reionization and the high spatial resolution observations of galaxies at higher redshift that are produced with gravitational lensing. In the last decade an exciting population of extremely low-metallicity star-forming galaxies have been discovered in the local universe. This sample provides the first laboratories of massive star populations at metallicities similar to those during the Reionization Era. Using deep UV and optical spectra of two galaxies in this sample, we have found that both galaxies have unprecedentedly large emission lines from very high-ionization species. We demonstrate that canonical photoionization models, using typical stellar populations, catastrophically fail to reproduce the high-ionization emission lines. We propose an additional ionizing source to reproduce the entire suite of emission lines observed in these extreme emission line galaxies. Finally, we will show the next steps to test which sources might produce these emission lines in other local galaxies with additional data from IR to X-rays and how they might change in galaxies at higher redshift with spatially-resolved data from gravitational lensing with JWST.

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Michael Blanton

Thursday, July 23, 2026 - 11:00am

Title TBA

Abstract TBA

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Even Nuñez

Thursday, July 30, 2026 - 11:00am

Unveiling Galaxy Evolution using Distant Dark “Clouds"

In this talk I will summarize my academic journey thus far, and various aspects of galaxy evolution that can be studied using distant, light absorbing “clouds" known as QSO absorbers. In particular, I will show QSO absorbers' utility in placing empirical constraints on galactic chemical evolution during the earliest epochs of the universe, and recent exciting progress in the long standing quest to understand the role and impact of "galactic atmospheres” (also known as the circumgalactic medium) on a galaxy’s evolution throughout cosmic time.

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Samantha Wu

Thursday, August 6, 2026 - 11:00am

Viewing the volatile lives of massive stars via interacting supernovae

Observations of core collapse supernovae have revealed the presence of dense circumstellar material (CSM) near the exploding progenitors and uncovered a gap in our understanding of stellar evolution. While this CSM must originate from pre-supernova mass loss in massive stars, the underlying mechanism remains uncertain. I will discuss the successes and challenges of a few theories to explain CSM in interacting supernovae, including wave-driven mass loss and binary interactions.

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Nondh Panithanpaisal

Thursday, August 13, 2026 - 11:00am

Near-field Cosmology with Stellar Streams

The outer region of our Milky Way, known as the Galactic halo, is filled with substructures formed through hierarchical assembly. Among these substructures, stellar streams, which are the remnants of disrupted dwarf galaxies and globular clusters, stand out as powerful tools for studying both the properties of the Galactic halo and the nature of dark matter. In this talk, I will introduce populations of simulated dwarf galaxy stellar streams from the FIRE-2 cosmological simulations of Milky Way-mass galaxies. By comparing these simulated streams with those observed in the Milky Way, I will show how the number of detectable streams can be used to constrain different dark matter models. I will conclude the talk with recent efforts to simulate globular cluster stellar streams and discuss how they can provide complementary constraints on the nature of dark matter.