# UVIT view of dwarf irregular galaxy IC 2574 : Is the star formation triggered due to expanding H$~$I shells?

## TL;DR

This study uses UVIT FUV imaging to analyze star formation in dwarf galaxy IC 2574, revealing that some star formation is triggered by expanding H I shells, but other mechanisms also play a role.

## Contribution

First detailed FUV imaging analysis of IC 2574 linking star formation to expanding H I shells and other processes.

## Key findings

- 28.6% of FUV regions are in H I shells
- 30 out of 48 H I holes show triggered star formation
- Star formation rate is 0.57 solar masses per year

## Abstract

Star forming dwarf galaxies in the local volume are diverse and are ideal test beds to understand details of star formation in a variety of environments. Here, we present a deep FUV imaging study of a nearby dwarf irregular galaxy IC 2574 using the Ultraviolet Imaging Telescope (UVIT). We identified 419 FUV bright regions with radii between 15 - 285 pc in the galaxy and found that 28.6\% of them to be located in H~I shells, 12.6\% inside holes and 60.1\% to be away from the holes. The H~I column density is found to be more than $10^{21} cm^{-2}$ for 82.3\% of the identified regions. 30 out of the 48 H~I holes show triggered star formation in their shells while 16 holes do not show any related FUV emission. Cross-matching with H$\alpha$ emission, we found that 23 holes have both FUV and H$\alpha$ emission in their shells signifying very recent trigger. Therefore, star formation in the galaxy has been partly triggered due to the expanding H~I holes whereas in majority of the sites it is driven by other mechanisms. Irrespective of the location, larger star forming complexes were found to have multiple sub-structures. We report two resolved components for the remnant cluster of the super giant shell and estimated their masses. The star formation rate of IC 2574 is found to be 0.57 $M_{\odot}$/yr, which is slightly higher compared to the average value of other nearby dwarf irregular galaxies.