High-velocity-resolution observations of OH main line lasers in the M82 starburst

TL;DR

This study used high velocity resolution VLA observations to analyze OH maser emissions in M82's starburst region, revealing detailed velocity structures and their relation to the galaxy's gas dynamics.

Contribution

It provides the first high-resolution velocity structure of OH masers in M82, enhancing understanding of gas motions in starburst environments.

Findings

Detected 13 masers, including all but one previously known.

Revealed velocity structures in several maser spectra.

Showed agreement between maser velocity distribution and HI gas dynamics.

Abstract

Using the VLA, a series of high velocity resolution observations have been made of the M82 starburst at 1.6 GHz. These observations follow up on previous studies of the main line OH maser emission in the central kiloparsec of this starburst region, but with far greater velocity resolution, showing significant velocity structure in some of the maser spots for the first time. A total of thirteen masers were detected, including all but one of the previously known sources. While some of these masers are still unresolved in velocity, these new results clearly show velocity structure in spectra from several of the maser regions. Position-velocity plots show good agreement with the distribution of H{\sc i} including interesting velocity structure on the blueward feature in the west of the starburst which traces the velocity distribution seen in the ionised gas.