MAXI/GSC detection of a big flare from GT Mus
ATel #8285; S. Kanetou (Chuo U.), H. Negoro (Nihon U.), Y. Tsuboi, Y. Nakamura, R. Sasaki (Chuo U.), T. Takagi (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, M. Matsuoka (RIKEN), N. Kawai, M. Arimoto, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, R. Imatani (Osaka U.), M. Nakajima, K. Tanaka, T. Masumitsu (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.), M. Yamauchi, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.), M. Morii (ISM)
on 16 Nov 2015; 06:14 UT
Credential Certification: Yohko Tsuboi (tsuboi@phys.chuo-u.ac.jp)
Subjects: X-ray, Binary, Star, Transient, Variables
At 14:04:28UT on November 15th 2015, the MAXI/GSC nova alert system triggered on a bright source at a position consistent with that of an RS CVn star GT Mus. The flux started to increase at 22:38:30 UT on November 14th 2015, and it is still high at 12:30:30 UT on November 15th with a value of100+10.0-45.0 mCrab (68.00% confidence) in the 2-20 keV band. This is the largest flare from GT Mus among those detected with the MAXI/GSC. In the past, the MAXI/GSC detected three flares and the highest flux was recorded as 50 mCrab in November 2010 (M. Nakajima et al. 2010, ATEL#3021),
The position was determined with the data from 10:59:30 UT on November 15th 2015 to 12:30:30 UT on the same day, as (R.A., Dec) = (174.89 deg, -65.42deg) = (11 39 34, -65 25 14) (J2000) with a statistical 90% C.L. elliptical error region with long and short radii of 0.32 deg and 0.28 deg respectively. The roll angle of long axis from the north direction is 19.4 deg. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). This position is consistent with that of an RS CVn star GT Mus. No other source is listed in the ROSAT Bright Source Catalog in this error region.
