Class I methanol masers in low-mass star formation regions

TL;DR

This study reports the detection of Class I methanol masers in low-mass star formation regions, expanding understanding of maser phenomena beyond high-mass star-forming environments.

Contribution

It presents the first detections of Class I methanol masers in low-mass star formation regions and compares their properties to those in high-mass regions.

Findings

Detected four new masers at 44, 84, and 95 GHz in low-mass regions.

Brightness temperatures exceed 2000 K in some sources, indicating strong maser activity.

Masers in low-mass regions share properties with those in high-mass regions.

Abstract

Four Class I maser sources were detected at 44, 84, and 95 GHz toward chemically rich outflows in the regions of low-mass star formation NGC 1333I4A, NGC 1333I2A, HH25, and L1157. One more maser was found at 36 GHz toward a similar outflow, NGC 2023. Flux densities of the newly detected masers are no more than 18 Jy, being much lower than those of strong masers in regions of high-mass star formation. The brightness temperatures of the strongest peaks in NGC 1333I4A, HH25, and L1157 at 44 GHz are higher than 2000 K, whereas that of the peak in NGC 1333I2A is only 176 K. However, rotational diagram analysis showed that the latter source is also a maser. The main properties of the newly detected masers are similar to those of Class I methanol masers in regions of massive star formation. The former masers are likely to be an extension of the latter maser population toward low luminosities of both the masers and the corresponding YSOs.