The Arecibo Methanol Maser Galactic Plane Survey - II: Statistical and Multi-wavelength Counterpart Analysis

TL;DR

This study analyzes 6.7 GHz methanol masers from the Arecibo survey, revealing their association with massive star formation, estimating their galactic population, and providing spectral property insights.

Contribution

It offers the first comprehensive statistical and multi-wavelength analysis of the Arecibo methanol maser sample, including galactic distribution and spectral characteristics.

Findings

Estimated minimum of 1275 methanol masers in the Galaxy.

Detected tangent point of the Carina-Sagittarius arm at 49.6 degrees.

Mean maser line-width is 0.38 km/s, larger than previous reports.

Abstract

We present an analysis of the properties of the 6.7 GHz methanol maser sample detected in the Arecibo Methanol Maser Galactic Plane Survey. The distribution of the masers in the Galaxy, and statistics of their multi-wavelength counterparts is consistent with the hypothesis of 6.7 GHz maser emission being associated with massive young stellar objects. Using the detection statistics of our survey, we estimate the minimum number of methanol masers in the Galaxy to be 1275. The l-v diagram of the sample shows the tangent point of the Carina-Sagittarius spiral arm to be around 49.6 degrees, and suggests occurrence of massive star formation along the extension of the Crux-Scutum arm. A Gaussian component analysis of the maser spectra shows the mean line-width to be 0.38 km/s which is more than a factor of two larger than what has been reported in the literature. We also find no evidence that faint methanol masers have different properties than those of their bright counterparts.