MAXI/GSC detection of a possible X-ray flare from an RS CVn star V824 Ara
ATel #6908; H. Ohtsuki (AGU), S. Kanetou (Chuo U.), S. Nakahira (JAXA) ,M. Serino, (RIKEN), Y. Tsuboi, A. Kawagoe (Chuo U.), S. Ueno, H. Tomida, M. Kimura, M. Ishikawa, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Kawakubo (AGU), H. Tsunemi, D. Uchida (Osaka U.), H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki, T. Namba, M. Fujita, F. Honda (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team
on 13 Jan 2015; 12:06 UT
Credential Certification: Yohko Tsuboi (tsuboi@phys.chuo-u.ac.jp)
Subjects: X-ray, Binary, Star, Transient, Variables
MAXI/GSC observed a possible X-ray flare from an RS CVn star V824 Ara. The flux increase was detected at 16:28:18 UT on January 11th 2015. The flux decay was confirmed at 18:02:38 UT on the same day.
The position of the X-ray enhancement is (260.142 deg, -67.092 deg) = (17 20 34, -67 05 30) (J2000) with a statistical 90% C.L. circle error region with a radius of 0.37 deg. The position was determined with the data obtained at the scan transit from 16:28:18 UT on January 11th to 16:37:14 UT on the same day. There is an additional systematic uncertainty of 0.1 deg (90% containment radius). This position is consistent with that of an RS CVn star, V824 Ara, which is listed in the ROSAT Bright Source Catalog. No other source listed in the catalog is in the error region. The 4-10 keV flux at 16:28:18 UT on January 11th was about 90+-23 mCrab. These are corresponding to a luminosity of 2× 10 32 ergs/s for an assumed distance of 31 pc. This is the first detection of this source with MAXI/GSC.
