IAUS379: Dynamical Masses of Local Group Galaxies

Proper Motions of M31 Satellite Galaxies: M31 Mass, Satellite Orbits, and the Dynamical State of the Satellite Plane

21 Mar 2023, 11:30

25m

Haus H, Telegrafenberg

Invited topical talk SESSION 2 : Sizes, Masses, and Formation histories of the Milky Way and of Andromeda SESSION 2 : Sizes, Masses, and Formation histories of the Milky Way and of Andromeda

Speaker

Tony Sohn (Space Telescope Science Institute)

Description

Proper motions (PMs) from HST and Gaia have revolutionized the field of Galactic archaeology in the Milky Way (MW). However, PM studies in and around our neighbor spiral galaxy M31 are still in their early stages with measurements being available for only a few satellites and M31 itself at the moment. Gaia can only detect some of the brightest stars in star forming regions at the distance of M31, so HST and JWST remain the only reliable options for measuring PMs of M31 satellite dwarf spheroidals. Three-dimensional kinematics based on PM measurements of satellites will allow constraining the total mass of M31 and testing the dynamical stability of the Great Plane of Andromeda. Furthermore, orbital histories of individual satellites based on the PM results will provide clues to disentangle the processes that have contributed to the quenching of star formation and help connect some satellite galaxies to M31 substructures. In this contribution, I will present the progress of our HST and JWST programs to measure PMs of M31 satellite galaxies.