AR 16628 (Archival Research)

Sun Jul 14 20:50:19 GMT 2024

Principal Investigator: Ekta Patel
PI Institution: University of Utah
Investigators (xml)

Title: Establishing a New Framework for Quantifying Quenching in Low-Mass Satellite Galaxies using Gaia and HST
Cycle: 29

We propose to combine Gaia- and HST-based orbital histories with HST-based star formation histories (SFHs) for five classical Milky Way (MW) satellites (M* = 10^5-10^7 Msun; Carina, Fornax, Leo I, Leo II, Phoenix I) to quantify the processes by which low-mass satellites galaxies quench. Specifically, we will correlate the timing and frequency of orbital parameters (e.g., location in halo, velocity, number of orbits) with star formation episodes (bursts, dips, overall decline) to provide data-driven insight into how low-mass satellites transition from star-forming to quenched as they orbit within the halo of a massive galaxy. These five classical MW satellites have exquisite 6D phase space information (3D position + 3D velocity) from Gaia and HST, and well-populated color-magnitude diagrams (CMDs) from archival HST programs, allowing for precise SFH recovery over the past several Gyr. In the era of precise SFHs and orbital histories, this program will establish the framework necessary to move beyond two point comparisons of infall time and quenching time commonly used in studies of low-mass galaxy quenching. Through a joint analysis of detailed SFHs and precise orbital histories, we will paint a clear picture of where, when, and how low-mass MW satellite galaxies quench. This program leverages substantial ongoing HST investments aimed at measuring SFHs and proper motions (PMs) of Local Group dwarf galaxies. The results and infrastructure established and published by this program will serve as important templates for quantifying the quenching process as more low-mass satellite galaxy SFHs and PMs are measured by HST and JWST.