February 11
The Formation of Compact Elliptical Galaxies via Tidal Stripping Scenarios from Resolved Stellar Kinematics in M32
Dr. Ivanna Escala
Space Telescope Science Institute
Abstract: The formation of low-mass compact elliptical galaxies beyond the typical regime of galaxy scaling relations has long challenged our understanding of galaxy evolution. However, the tidal disruption of satellite galaxies by a massive host may provide a formation pathway for these rare systems. As the only compact elliptical close enough to resolve into individual stars, the satellite dwarf galaxy M32 offers a unique opportunity to explore whether compact ellipticals form via tidal stripping of a progenitor galaxy. M32 is a metal-rich outlier on the stellar mass-metallicity relation, contains a central black hole, and experienced a starburst 2–5 Gyr ago coincident with that of the disk of its host galaxy, M31 — all of which suggest a possible origin in a massive progenitor. Yet dynamical evidence of its interaction with M31 has remained elusive due to observational challenges. In this talk, I will present the first detection of kinematical signatures supporting the tidal distortion of M32 from interactions with M31 based on novel data from the Spectroscopic and Photometric Landscape of Andromeda’s Stellar Halo (SPLASH) survey combined with HST imaging from the Panchromatic Hubble Andromeda Southern Treasury (PHAST). I will discuss the implications of M32’s internal kinematics for our broader understanding of compact elliptical formation, and I will highlight future directions on modeling the total mass distribution and orbit of M32.
Host: Ankita Bera