Triggered star formation in giant HI supershells: ionized gas

TL;DR

This study investigates triggered star formation within giant HI supershells in three dwarf galaxies, revealing faint ionized shells inside the HI structures and exploring their impact on galaxy evolution.

Contribution

It presents the first observation of faint giant ionized shells inside supergiant HI shells in dwarf galaxies, linking ionized gas morphology to star formation processes.

Findings

Discovery of faint giant ionized shells inside HI supershells.

Analysis of gas morphology and kinematics in three dwarf galaxies.

Insights into how star formation influences supershell evolution.

Abstract

We considered the regions of triggered star formation inside kpc-sized HI supershells in three dwarf galaxies: IC 1613, IC 2574 and Holmberg II. The ionized and neutral gas morphology and kinematics were studied based on our observations with scanning Fabry-Perot interferometer at the SAO RAS 6-m telescope and 21 cm archival data of THINGS and LITTLE THINGS surveys. The qualitative analysis of the observational data performed in order to highlight the two questions: why the star formation occurred very locally in the supershells, and how the ongoing star formation in HI supershells rims influence its evolution? During the investigation we discovered the phenomenon never observed before in galaxies IC 2574 and Holmberg II: we found faint giant (kpc-sized) ionized shells in H-alpha and [SII]6717,6731 lines inside the supergiant HI shells.