Optical identification of the FASHI sources: toward the extended Local Volume

TL;DR

This study identified 662 nearby HI sources from the FASHI survey and visually matched them with optical counterparts, discovering 71 new dwarf irregular galaxies with ongoing star formation.

Contribution

The paper presents the first optical identification of FASHI HI sources, including the discovery of 71 new dwarf irregular galaxies within 16 Mpc.

Findings

Discovered 71 new dwarf irregular galaxies with ongoing star formation.

Characterized the median properties of these galaxies, including magnitude, color, and HI mass.

Provided a catalog of nearby HI sources with optical counterparts.

Abstract

We extracted a list of 662 nearby (within $\sim16$ Mpc) HI-detection sources from the Five-hundred-meter Aperture Spherical radio Telescope (FAST) All Sky HI Survey (FASHI) and made a visual identification of them with optical counterpart. This inspection led to the discovery of 71 new dwarf galaxies. All of them are dwarf irregular galaxies with ongoing star formation. They are characterized by the following median parameters: visual magnitude of $g=17.8$ mag and color $(g-r)=0.29$ mag, HI-flux $S_\mathrm{HI}=718$ mJy km/s, HI-mass $M_\mathrm{HI}=3.7\times10^7$ $M_\odot$, as well as the HI line-width of $W_{50}=37$ km/s.