Detection of Dense Clusters of Water Vapor Maser Sources during Powerful Flares in the IRAS 16293-2422

Abstract

Based on long-term monitoring data of the water maser transition at 22.2 GHz from 2019 to 2021 we were able to detect two powerful phenomena in IRAS 16293-2422 that lasted in total about a year and that occurred at radial velocities near 6 and 8 km s–1. In both cases, powerful short flares were located on the top of less powerful, but more prolonged ones (4 and 0.6 kJy). Their radiation initiated the release of more powerful flares. Thanks to long-term detailed observations of water masers, the exist-ence of the several emitting maser spot configurations with very close radial velocities, located in the line of sight of the observer were confirmed for the first time. This made it possible to demonstrate the correctness of the water maser activation hypothesis based on an increase in the amplification length of the maser due to several maser condensations located in the line of sight of the observer. The unsaturated state of the most powerful and shortest maser flares, as well as the saturated state of the weaker ones, has been observed. New important parameters of the water masers and the as-sumed location of the maser spots have been obtained.