Title: MAXI/GSC detected an intense X-ray flare from an RS CVn star VY Ari
ATel #9044; Y. Nakamura, R. Sasaki, Y. Tsuboi(Chuo U.), H. Negoro (Nihon U.), S. Ueno, H. Tomida, S. Nakahira, M. Ishikawa, Y. E. Nakagawa, Y. Sugawara (JAXA), T. Mihara, M. Sugizaki, M. Serino, W. Iwakiri, M. Shidatsu, J. Sugimoto, T. Takagi, M. Matsuoka (RIKEN), N. Kawai, N. Isobe, S. Sugita, T. Yoshii, Y. Tachibana, Y. Ono, T. Fujiwara (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo, Y. Kitaoka (AGU), H. Tsunemi, R. Shomura (Osaka U.), M. Nakajima, K. Tanaka, T. Masumitsu, T. Kawase (Nihon U.), Y. Ueda, T. Kawamuro, T. Hori, A. Tanimoto (Kyoto U.), M. Yamauchi, K. Furuya (Miyazaki U.), K. Yamaoka (Nagoya U.)
on 12 May 2016; 09:16 UT
Credential Certification: Yohko Tsuboi (tsuboi@phys.chuo-u.ac.jp)
Subjects: X-ray, Binary, Star, Transient, Variables
On May 12 2016, the MAXI/GSC detected an enhanced X-ray emission at a position consistent with that of an RS CVn star VY Ari. The flux peak was observed at a transit starting at 12:34 UT on 11 May 2016 with a value of 146+-35 mCrab (90% error) in the 4-10 keV band, corresponding to a luminosity of 5×1032 ergs/s for an assumed distance of 44 pc. At the next scan starting at 14:08 on 11 May 2016, the observed flux was 83+-26 mCrab (90% error) in the 4-10 keV, corresponding to a luminosity of 4×1032 ergs/s.
In the past, the MAXI/GSC detected four flares and the highest flux was recorded as 62 mCrab in July 2015 (ATel #7839).
The position was determined from the data at the flare peak, as (R.A., Dec) = (42.180 deg, 31.196 deg) = (02 48 43, +31 11 44) (J2000) with a statistical 90% C.L. circle error region with radii of 0.33 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 VY Ari . No other source is listed in the ROSAT Bright Source Catalog in this error region.
