SMA Observations of Haro 2: Molecular Gas around a Hot Superbubble

TL;DR

This study uses high-resolution CO(2-1) observations to analyze molecular gas in Haro 2, revealing two components associated with starburst activity and outflows, and suggesting feedback effects on the galaxy's molecular environment.

Contribution

It provides detailed high-resolution mapping of molecular gas in Haro 2, linking molecular features with starburst-driven outflows and feedback processes.

Findings

Molecular gas consists of bright clumps and extended emission.

Extended emission aligns with an X-ray bubble and shows expansion signatures.

Starburst winds likely entrain molecular gas, affecting galaxy evolution.

Abstract

Haro 2 , a nearby dwarf starburst dwarf galaxy with strong Ly alpha emission, hosts a starburst that has created outflows and filaments. The clear evidence for galactic outflow makes it an ideal candidate for studying the effects of feedback on molecular gas in a dwarf galaxy. We observed CO(2-1) in Haro 2 at the Submillimeter Array in the compact and extended configurations, and have mapped the molecular emission with velocity resolution 4.1 km/s and spatial resolution 2.0x1.6". With this significant increase of resolution over previous measurements we see that the molecular gas comprises two components: bright clumps associated with the embedded star clusters of the starburst, and fainter extended emission east of the starburst region. The extended emission coincides with an X-ray bubble and has the kinematic signatures of a shell or bubble expanding with velocity +-35 km/s. We suggest that the starburst winds that created the X-Ray bubble have entrained molecular gas, and that the apparent velocity gradient across the photometric axis is an artifact caused by the outflow. The molecular and X-ray activity is on the east of the galaxy and the ionized outflow and optical filaments are west; their relationship is not clear.