Galaxies and Cosmology Seminar
Mar
23
2026
Mar
23
2026
Description
Chaos at Cosmic Dawn: Constraining the origins of stochasticity in galaxy formation
Successful pre-JWST galaxy formation models have failed to reproduce the observed abundance of bright galaxies at early times (𝑧 > 10). Possible explanations for this discrepancy include bursty star formation, which temporarily boosts the brightness of galaxies (particularly those in low-mass halos), or increased overall star formation efficiency, which increases the typical brightness of galaxies at a fixed halo mass. We have created a flexible analytic framework for modeling the UV luminosity function (UVLF) with mass-dependent scatter. We present a joint analysis of the HST (𝑧 = 4 − 7) and JWST (𝑧 = 8 − 12.5) UVLFs. We find that models with constant 𝜎UV cannot explain the 𝑧 ≳ 10 UVLF. However, we reproduce these data with modest global star formation efficiency provided that scatter increases at 𝑧 ≳ 9. UVLF measurements allow for significant bursty star formation, though do not require it to explain the data.
Other Events in This Series
Jan
13
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar
No meeting
12:00 pm – 1:00 pm • In Person
Jan
20
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar
Dr. Martin Luther King, Jr. Day - UT Closed
12:00 pm – 1:00 pm
Jan
27
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar
Organizational Meeting
12:00 pm – 1:00 pm
Feb
3
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar: The Mysterious Galaxy at z = 0: A Rosetta Stone for Galaxy-scale Star Formation
Neal Evans is a Professor Emeritus in the Department of Astronomy
12:00 pm – 1:00 pm
Speaker(s): Neal Evans - The University of Texas at Austin
Feb
10
2025
Galaxies and Cosmology Seminar
Special Seminar: Causal AI in Astronomy
Special Seminar by Peter Melchior of Princeton University
12:00 pm – 1:00 pm
Speaker(s): Peter Melchior - Princeton University
Feb
17
2025
Galaxies and Cosmology Seminar
Special Seminar: Machine Learning at the Cosmic Frontiers - Discovering what shaped the past lives of galaxies with novel astrostatistical methods
Special Seminar by Kartheik Iyer of Columbia University
12:00 pm – 1:00 pm
Speaker(s): Kartheik Iyer - Columbia University
Feb
24
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar: Physical Pathways for JWST-Observed Supermassive Black Holes in the Early Universe
Seminar talk by graduate student Junehyoung Jeon
12:00 pm – 1:00 pm
Speaker(s): Junehyoung Jeon - The University of Texas at Austin
Mar
3
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar
Two talks by Astronomy Department graduate students
12:00 pm – 1:00 pm
Speaker(s): Connor Painter - The University of Texas at Austin and Maria Straight - The University of Texas at Austin
Mar
10
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar
Two talks by Astronomy Department graduate students
12:00 pm – 1:00 pm
Speaker(s): Om Gupta - The University of Texas at Austin and Emily Bregou - The University of Texas at Austin
Mar
24
2025
Galaxies and Cosmology Seminar
Galaxies and Cosmology Seminar
Two talks by Astronomy Department graduate students
12:00 pm – 1:00 pm
Speaker(s): Natalia Villanueva and Kaelee Parker - The University of Texas at Austin