GBT26A-113

HI Survey of Recently Discovered Southern Dwarf Galaxies

Abstract

We propose to extend our ongoing and very successful HI survey of Local Volume (LV) dwarf galaxies to the southern sky. The target galaxies were recently identified through a visual inspection of a wide area of the DESI Legacy Imaging Survey located outside the FASHI survey footprint. The sample has been supplemented with known LV galaxies that have not been previously observed in HI. These galaxies exhibit irregular morphologies and angular sizes of ~1 arcminute, consistent with low-mass systems within ~12 Mpc. Their blue stellar populations suggest ongoing or recent star formation and imply the presence of a significant reservoir of neutral gas.

In GBT/23B-032 and GBT/24B-157 we obtained HI spectra for 105 similar galaxies. The scientific return is substantial: HI was detected with high significance in ~73% of the sample, and 43 galaxies were confirmed to reside within the LV. Here we aim to observe 37 galaxies in order to characterize their neutral ISM for the first time. Our primary science goals are to measure the fundamental HI properties and to motivate follow-up interferometric observations to probe their physical characteristics. Our observational strategy is sensitive to HI masses as low as ~1E6 Solar masses for galaxies within the LV.

Investigators

Name	Institution
Alexandra Nazarova *	Special Astrophysical Observatory; Saint Petersburg State University
Dmitry Makarov	Special Astrophysical Observatory
John Cannon	Macalester College
Igor Karachentsev	Special Astrophysical Observatory

* indicates the PI