Bursting activity of the 6.668-GHz CH3OH maser detected in G 358.93-00.03 using the Hitachi 32-m
ATel #12446; Koichiro Sugiyama (National Astronomical Observatory of Japan), Yu Saito, Yoshinori Yonekura, and Munetake Momose (Ibaraki University)
on 29 Jan 2019; 07:39 UT
Credential Certification: Koichiro Sugiyama (koichiro.sugiyama@nao.ac.jp)
Subjects: Radio, Variables, Young Stellar Object
A bursting activity as a drastic flux rising has been detected in the 6.668-GHz CH3OH maser associated with the star-forming region G 358.93-00.03. The 6.668-GHz CH3OH maser in G 358.93 was firstly reported by Caswell et al. (2010, MNRAS, 404, 1029) with the peak flux density of 10 Jy at Vlsr = -15.9 km/s on 2006 Mar 31. Using the Hitachi 32-m radio telescope, we initiated a flux monitor observation of the CH3OH maser in G 358.93 on 2013 Jan 2, and its flux density had been weaker than 10 Jy until 2018 Oct 31. Although the subsequent observation in our monitor had been conducted 75 days later, the peak flux density at Vlsr = -15.9 km/s increased to 11 Jy on 2019 Jan 14 and two days later on 2019 Jan 16 other spectral feature at Vlsr = -15.4 km/s suddenly showed a flux rising from 9 Jy to 19 Jy. Five days later on 2019 Jan 21 the spectral feature at Vlsr = -15.9 km/s came back to the brightest one as a flux density of 19 Jy. Daily flux monitor since then has revealed a drastic flux rising as follows: 31 Jy on Jan 22, 49 Jy on Jan 23, 70 Jy on Jan 24, 89 Jy on Jan 25, and 99 Jy on Jan 26. During the flux rising at Vlsr = -15.9 km/s, other eight spectral features in Vlsr from -19.8 to -14.3 km/s showed flux risings together.
Figures of comparisons among spectra observed in each date and flux variations for each spectral feature can be seen at the following URL:
http://vlbi.sci.ibaraki.ac.jp/iMet/G358.9-00-190114/
