GBT25B-122

Newly Discovered Local Volume Dwarf Galaxies

Abstract

We have discovered previously unknown candidates for Local Volume dwarf galaxies by visually searching a large area of the DESI Legacy Imaging Survey. This sample has been complemented by recently discovered objects that reside outside the FASHI survey area and not previously observed in HI. These dwarfs are characterized by irregular morphology and sizes of about 1 arcmin, suggesting that they are low-mass galaxies within ~12 Mpc. The blue colors of the stellar populations indicate recent star formation and the presence of a significant neutral ISM. In GBT/23B-032 and GBT/24B-157 we acquired HI spectra of 105 similar galaxies. The scientific payoff is rich: HI is detected at high significance in ~73% of the sample, and 41 of the sources are confirmed to be Local Volume dwarfs (D<12 Mpc). Here we propose observations of the 37 galaxies in order to characterise their neutral ISM for the first time. The primary science goals are to measure the fundamental HI properties of the galaxies and to motivate follow-up interferometric observations that will further probe their physical characteristics. Our observational strategy ensures that we are sensitive to HI masses as low as ~1E6 Solar masses for galaxies within the Local Volume (velocities <~3500 km/s).

Investigators

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

* indicates the PI