Anthony Gomes | 2026 I.S. Symposium
±·²¹³¾±ð:ÌýAnthony Gomes
°Õ¾±³Ù±ô±ð:ÌýQuantifying Clumpy Galaxies: Inferring Turbulent Jeans Mass from Galaxy Imaging
²Ñ²¹Âá´Ç°ù:ÌýPhysics
Advisor: Laura DeGroot
High-redshift galaxies around cosmic noon frequently display irregular, clumpy appearances quite different from the smooth, spiral galaxies common in the nearby universe. This work
develops a physically motivated method for characterizing where and why galaxies form clumps, applied to James Webb Space Telescope (JWST) imaging from the Cosmic Evolution Early Release Science (CEERS) Survey. For a sample of 24 galaxies, we calculated two key quantities: the Toomre stability parameter Q, which measures how susceptible a rotating gas disk is to gravitational collapse, and the turbulent Jeans mass MJ , which estimates the minimum mass of gas needed for a clump to collapse under its own gravity despite turbulent pressure. Both star formation rate surface density and gas surface density increased systematically with redshift, consistent with galaxies at earlier cosmic times containing larger reservoirs of raw star-forming material. Galaxies in the low-stability regime (Q = 1–20) had a median gas surface density of 17.6 M⊙ pc^−2 and a median clump mass scale of 2.95 ×10^9 M⊙, consistent with the observed masses of giant star-forming clumps seen in high-redshift imaging, while more gravitationally stable systems showed clump mass scales roughly 2.6 times larger and star formation rate surface densities three orders of magnitude lower, which was confirmed though visual inspection of JWST images. Together, these results show that standard observable galaxy properties, combined with disk instability theory, provide a reproducible and physically grounded framework for quantifying clump formation in distant star-forming galaxies.
Posted in Symposium 2026 on May 1, 2026.
