Project:	Census of low-mass galaxies with the Hubble Space Telescope
Disciplines:	Astronomy, Astrophysics
Mentor:	Michael Jones, Assistant Scientist, (PMA), mgjones@ipac.caltech.edu
Background:	One of the fundamental questions in extra-galactic astronomy is: how typical is the Milky Way? The Milky Way hosts dozens of dwarf galaxy satellites, which, owing to their proximity, are some of the best-studied low-mass galaxies. Galaxy formation simulations have been tuned to reproduce the abundance and global properties of these satellites, yet recent work has called into question how representative the Milky Way’s satellite system is, and raised the possibility that we may be aligning models with an outlier. Our ongoing imaging program with the Hubble Space Telescope is directly addressing this issue by performing a complete census of hundreds of dwarf galaxies around dozens of nearby Milky Way-like hosts. The exceptional resolution of Hubble images means that our target dwarf galaxies are fully resolved into individual stars, enabling their stellar populations to be characterized in a level of detail that would be impossible from the ground. This census will provide a definitive assessment of the abundance and properties of satellites in such systems, forming a foundational dataset for future studies and models of satellite galaxies.
Description:	The SURF student will work on the analysis of the resolved stellar populations in these Hubble Space Telescope images, determining highly accurate distances to our targets and separating genuine satellites from interlopers; a vital step that is only possible with space-based imaging. Working mostly in Python (and some Matlab) the student will help to refine our existing distance measurement algorithm so that it can be run en masse for the entire dataset. The student’s primary advisor will be Dr. Michael Jones at Caltech, however, they will also interact with the entire project team, based all across the US, on Zoom. Preference will be given to Caltech students, but all those interested in applying for the project should email mgjones@ipac.caltech.edu and include a description of their relevant experience and interests.
References:	Detailed star formation histories of three ultra-faint dwarf galaxies near Andromeda from fitting their resolved stellar populations: https://ui.adsabs.harvard.edu/abs/2025arXiv250800984J/abstract Demonstration of the distance determination method for dwarf galaxies in the nearby galaxy group Centaurus A: https://ui.adsabs.harvard.edu/abs/2019ApJ...872...80C/abstract Comparison of satellite properties in existing samples: https://ui.adsabs.harvard.edu/abs/2023MNRAS.524.5314K/abstract Parent sample of satellite candidates: https://ui.adsabs.harvard.edu/abs/2022ApJ...933...47C/abstract
Student Requirements:	Applicants do not need to have prior experience working with astronomy data, but should have a background and interest in astronomy/astrophysics/physics. They should also have experience programming in Python (experience with Matlab is also beneficial) and be familiar with fundamental statistical concepts.
Programs:	This AO can be done under the following programs:   Program    Available To        SURF    both Caltech and non-Caltech students  Click on a program name for program info and application requirements.