Methanol Masers Observations in the 3-mm Bandwidth at the Radio Telescope RT-22 CrAO

TL;DR

This paper reports initial observations of methanol masers at 95 GHz using a specialized 3-mm bandwidth receiver and spectrometer at the RT-22 radio telescope, confirming previous results and suggesting a link to molecular outflows.

Contribution

Introduction of a new observational setup for methanol masers in the 3-mm band and initial results aligning with prior findings.

Findings

Detection of methanol masers at 95 GHz in multiple regions.

Confirmation of previous maser observations with new equipment.

Indication of maser origins related to molecular outflows.

Abstract

We report the beginning of the astronomical masers investigations in the 3-mm bandwidth at the radio telescope RT-22 (CrAO, Ukraine). For this purpose the special complex for maser lines investigation in 85...115 GHz frequency band is developed. It is made on the base of the low noise cryogenic Shottky-diode receiver and the high resolution Fourier-spectrometer. The cryogenic receiver has the DSB noise temperature less than 100K. The spectral channel separation of the Fourier-spectrometer is about 4kHz and the spectrometer bandwidth is 8 MHz. Results of maser observations of 8$^{0}-7^{1} $A$^{+}$ transition of methanol (95.169 GHz) towards DR-21(OH), DR-21W and NGC7538 are in good agreement with early obtained results by other authors. On the basis of the analysis of the location of masers in the NGC7538 direction we can assume that the origin of all known class I methanol masers in this region is connected with existing molecular outflows from young stars.