Discovery of the first methanol (CH3OH) maser in the Andromeda galaxy (M31)

TL;DR

This paper reports the first detection of a 6.7 GHz methanol maser in the Andromeda galaxy, which could be used to measure M31's proper motion and improve understanding of the Local Group's dynamics.

Contribution

First identification of a methanol maser in M31, expanding the tools for studying galaxy motions beyond the Milky Way.

Findings

Detected a methanol maser in M31 using VLA and EVLA.

Confirmed the maser with new EVLA observations.

Failed to detect water maser at the same location.

Abstract

We present the first detection of a 6.7 GHz Class II methanol (CH3OH) maser in the Andromeda galaxy (M31). The CH3OH maser was found in a Very Large Array (VLA) survey during the fall of 2009. We have confirmed the methanol maser with the new Expanded VLA (EVLA), in operation since March 2010, but were unsuccessful in detecting a water maser at this location. A direct application for this methanol maser is the determination of the proper motion of M31, such as was obtained with water masers in M33 and IC10 previously. Unraveling the three-dimensional velocity of M31 would solve for the biggest unknown in the modeling of the dynamics and evolution of the Local Group of galaxies.