Gas rich galaxies from the FIGGS survey

TL;DR

This paper presents observations of two gas-rich dwarf galaxies with extended HI disks, offering insights into dark matter distribution and baryon fractions in faint galaxies.

Contribution

It provides detailed observational data on two extremely gas-rich dwarf galaxies, highlighting their extended gas disks and dark matter properties, expanding understanding of faint galaxy composition.

Findings

Extended HI disks trace dark matter distribution.

Gas-rich dwarfs may have low baryon fractions.

Comparison with other galaxies reveals unique dark matter characteristics.

Abstract

The FIGGS (Faint Irregular Galaxy GMRT Survey) is aimed at creating a multi-wavelength observational data base for a volume limited sample of the faintest gas rich galaxies. In this paper we discuss two very gas rich galaxies that were observed as part of the FIGGS survey, viz. NGC 3741 and And IV. These galaxies are unusual in that they have extremely extended gas disks and very high ratios of dark to luminous matter. The very extended HI disks provide an unique opportunity to trace the extended distribution of dark matter around faint galaxies. We compare the baryon fraction of these galaxies with a sample of galaxies with well measured rotation curves and discuss whether extremely gas rich dwarf galaxies have abnormally small baryon fractions.