Superflares of H$_2$O Maser Emission in the Protostellar Object IRAS 18316$-$0602

TL;DR

This study reports on the detection and analysis of three superflares in H$_2$O maser emission from the protostellar object IRAS 18316$-$0602 over 15 years, revealing their association with shock waves and high activity periods.

Contribution

First long-term monitoring of H$_2$O maser superflares in IRAS 18316$-$0602, providing insights into their timing, intensity, and possible shock wave association.

Findings

Three superflares detected with peak flux densities up to 46,000 Jy.

Superflares occurred during high maser activity periods within narrow velocity ranges.

2016 flare showed increased flux in multiple velocity features.

Abstract

The results of the study of the maser emission source IRAS 18316$-$0602 in the H$_2$O line at $\lambda =1.35$ cm are reported. The observations have been carried out at the RT-22 radio telescope of the Pushchino Radio Astronomy Observatory (Russia) since June 2002 until March 2017. Three superflares have been detected, in 2002, 2010, and 2016, with peak flux densities of 3400, 19,000, and 46,000 Jy, respectively. The results of the analysis of the superflares are given. The flares took place during periods of high maser activity in a narrow interval of radial velocities (40.5-42.5 km/s) and could be associated with the passage of a strong shock wave. During our monitoring the emission of three groups of features at radial velocities of about 41, 42, and 43 km/s dominated. The flare of 2016 was accompanied by a considerable increase in the flux densities of several features in an interval of 35--56 km/s.