MAXI/GSC detection of a renewed activity of the RS CVn star IM Peg
ATel #6322; A. Kawagoe, Y. Tsuboi (Chuo U.), M. Fujita (Nihon U.), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, M. Morii, M. Serino , J. Sugimoto, T. Takagi, A. Yoshikawa, M. Matsuoka (RIKEN), N. Kawai, R. Usui, T. Yoshii, Y. Tachibana (Tokyo Tech), A. Yoshida, T. Sakamoto, Y. Nakano, Y. Kawakubo, H. Ohtsuki (AGU), H. Tsunemi, M. Sasaki (Osaka U.), , H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), M. Yamauchi, Y. Morooka (Miyazaki U.), K. Yamaoka (Nagoya U.) report on behalf of the MAXI team
on 17 Jul 2014; 08:36 UT
Credential Certification: Yohko Tsuboi (tsuboi@phys.chuo-u.ac.jp)
Subjects: X-ray, Binary, Star
Referred to by ATel #: 6339
MAXI/GSC observed an X-ray enhancement at a position consistent with that of an RS CVn star IM Peg.
The flux started to increase at 06:56:57 UT on July 16th 2014, and dimmed at 14:41:31 UT on the same day.
Also, another enhancement was seen at 20:53:02 UT on July 16th.
The position of the X-ray enhancement is
(R.A., Dec) = (343.374 deg, 16.871 deg) = (22 53 29, +16 52 15) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.21 deg and 0.17 deg respectively.
The roll angle of long axis from the north direction is 76.0 deg
counterclockwise.
The position was determined with the data from 06:56:57 UT on July 16th to 20:53:02 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, IM Peg, which showed an X-ray active state
from 20:12:21 UT on July 5th to 17:52:19 UT on July 6th (Kawagoe et al. 2014, ATEL#6296).
No other source listed in the ROSAT Bright Source Catalog is in the error region.
The 4-10 keV flux averaged over four scan transits from 06:56:57 UT to 14:41:31 UT on July 16th
was about 35+-9 mCrab.
These are corresponding to a luminosity of 8× 10 30 ergs/s
for an assumed distance of 9.6 pc.
The light curve is updated daily at the following URL:
http://maxi.riken.jp/top/index.php?cid=1&jname=J2253+168 .
