Stellar Populations of Three Ultra Diffuse Galaxies in the Coma Cluster from the MaNGA Survey

A large population of ultra-diffuse galaxies (UDGs) was recently discovered in the Coma cluster.  We acquired optical spectra of three such UDGs, DF7, DF44 and DF17 from an ancillary program within SDSS IV/MaNGA survey, the Deep Coma program.  Stellar population models applied to these spectra enable measurements of recession velocities, ages and metallicities.  In this talk, I will present the stellar population analysis of these three UDGs through full spectral modeling.  The UDGs in our sample are as old or older than galaxies at similar stellar mass or velocity dispersion.  They all follow the well-established stellar mass-stellar metallicity relation.  These results, combined with the fact that UDGs are unusually large for their stellar mass, suggest that stellar mass plays a more important role in setting their stellar population properties than either size or surface brightness.  I will discuss their possible formation scenario, and will describe the current status of the ancillary Deep Coma program. 

Meng Gu (Harvard)
1st meeting room, KIAA
Wed, 2017-12-20 12:00 to 13:00