GBT20A-089

The HI content of Field Ultra-Diffuse Galaxies in SMUDGes

Abstract

We propose to measure the HI content of 58 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 their properties differ strongly from those of more typical, higher surface brightness systems, with some having the equivalent total mass of the Milky Way but only 1% as many stars. HI follow-up of field UDG candidates provides an efficient alternative to optical spectroscopy. Our initial HI follow-up campaign (GBT18A-239) confirmed 9 objects as UDGs, the largest sample with deep optical and HI data. The first stage of the full program (GBT19B-144) will target 63 UDG candidates in SDSS Stripe82 and in the Coma Cluster region, and will begin soon. This proposal to follow up an additional 58 candidates will complete our survey of Stripe82 and Coma. The 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 deepen 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