GBT19B-144

The HI content of Ultra-Diffuse Galaxies in SMUDGes

Abstract

We propose to measure the HI content of a complete sample (m_g<19.5) of 63 Ultra Diffuse Galaxy (UDG) candidates that we have identified in our survey, Systematically Measuring Ultra-Diffuse Galaxies (SMUDGes), in order to break the degeneracy between internal and external drivers of galaxy evolution. UDGs are critical to this endeavour because they are such an extremely different population from normal galaxies, with some having the equivalent total mass of the Milky Way but only 1% as many stars. Our previous project (GBT18A-239) focused on the region around the Coma Cluster. We confirmed 9 objects as UDGs, the largest sample with deep optical and HI data. In this proposal, we select potential targets on g-band magnitude assuming standard HI mass to stellar mass scaling relations for field spirals. A subset of the targets has UV counterparts suggesting that the are gas-rich and should be detected in HI. The resulting sample spans nearly a decade in surface brightness and is largely invisible in SDSS imaging. With the HI properties of this sample, we will directly test models of UDG formation and further our broader understanding of the role of environment on galaxy evolution.

Investigators

Name	Institution
Ananthan Karunakaran *	Toronto, University of
Kristine Spekkens	Queen's University
Dennis Zaritsky	Arizona, University of
Richard Donnerstein	Arizona, University of

* indicates the PI