GBT21B-304

Confirmation of filamentary HI structure in NGC5170 and NGC5253

Abstract

We propose to map the 21-cm emission line of neutral hydrogen, HI, in a 4 square degree region around two MHONGOOSE galaxies, NGC 5170 and NGC 5253. This will be a continuation of our previous, more shallow maps of these two galaxies, and with the addition of these proposed observations we will reach a combined HI column density 5???? detection limit of a few times 10^17cm-2 over a 20 km/s linewidth. We will build on our previous maps of these same galaxies with the goal of confirming potential filamentary structure seen at low signal-to-noise in the integrated intensity maps of both galaxies. We first observed these galaxies for 10 hours each as part of GBT project GBT/16B-212. Specifically, we propose to obtain an additional 20 hours for each galaxy, a total of 40 hours of new mapping time, for a combined (old map + new map) total integration time of 30 hours for each galaxy. A non-detection would result in setting an important constraint on the column density upper limits for detecting structure accreting from the IGM. If this structure is confirmed to be astrophysical, this will be the first direct detection of HI in emission accreting onto a galaxy.

Investigators

Name	Institution
Amy Sardone *	Ohio State University; West Virginia University
Nickolas Pingel	Wisconsin at Madison, University of; Australian National University

* indicates the PI