Detection of an OH 1665-MHz Maser in M33

TL;DR

This paper reports the first detection of an OH 1665-MHz maser in the galaxy M33, using VLA observations, revealing a source with luminosity comparable to the brightest Galactic masers.

Contribution

The study presents the first confirmed OH 1665-MHz maser detection in M33, expanding understanding of extragalactic maser occurrences.

Findings

First OH 1665-MHz maser detected in M33

Source luminosity comparable to brightest Galactic masers

Detection at specific coordinates with flux density of 24.1 mJy

Abstract

We report one OH 1665-MHz detection in new observations with the NSF's Karl G. Jansky Very Large Array. To the authors' knowledge, this is the first OH maser detection in M33. The source occurs at a position of $\alpha=23.50069(9)^{\circ}$ and $\delta = 30.67984(9)^{\circ}$ (J2000) and is unresolved at the beam size ($9."7$). Two H$\alpha$ sources from the Moody et al. (2017) catalogue --- C1-1 and C1-2 --- are consistent within the beam size. We find a peak flux density of 24.1 mJy in a 1.5 km s$^{-1}$ channel. At the distance of M33, the source's specific luminosity is consistent with the brightest Galactic OH 1665-MHz masers.