# Gas engaged in noncircular motions in LITTLE THINGS dwarf irregular galaxies

## TL;DR

This study analyzes noncircular gas motions in 22 dwarf irregular galaxies, revealing significant noncircular gas regions, their characteristics, and lack of correlation with star formation, using detailed HI data analysis.

## Contribution

It introduces a method to decompose HI data cubes into bulk and noncircular motions, providing new insights into gas dynamics in dwarf irregular galaxies.

## Key findings

- Half of the galaxies show significant noncircular gas motions.
- Large-scale filamentary structures are observed in some galaxies.
- No strong correlation between noncircular motions and star formation activity.

## Abstract

We have examined gas engaged in noncircular motions in 22 of the nearby LITTLE THINGS dwarf irregular galaxies. The HI data cubes have been deconvolved into kinematic components - bulk rotation and noncircular motions, to produce maps of integrated gas, velocity field, and velocity dispersion in the different components. We found significant regions of gas engaged in noncircular motions in half of the galaxies, involving 1%-20% of the total HI mass of the galaxy. In one galaxy we found a pattern in the velocity field that is characteristic of streaming motions around the stellar bar potential and star formation at the end of bar. Two galaxies have large-scale filamentary structures found in their outer disks, and these filaments could be transient instabilities in the gas. We found no spatial correlation between noncircular motion gas and enhanced star formation. We found noncircular motion gas in only one galaxy associated with higher HI velocity dispersion.