MAXI/GSC detection of a new hard X-ray transient source MAXI J1659-152
ATel #2873; H. Negoro (Nihon U.), K. Yamaoka, S. Nakahira (AGU), K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), T. Mihara, Y. E. Nakagawa, M. Sugizaki, M. Serino, T. Yamamoto, T. Sootome, M. Matsuoka (RIKEN), N. Kawai, M. Morii, K. Sugimori, R. Usui (Tokyo Tech), A. Yoshida (AGU), H. Tsunemi, M. Kimura (Osaka U.), M. Nakajima, H. Ozawa, F. Suwa (Nihon U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), Uzawa, K. Yamazaki, K. Matsumura (Chuo U.), report on behalf of the MAXI team
on 25 Sep 2010; 16:12 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Hitoshi Negoro (firstname.lastname@example.org)
Subjects: X-ray, Request for Observations, Transient
Referred to by ATel #: 2874, 2875, 2877, 2880, 2881, 2884, 2887, 2888, 2890, 2900, 2906, 2912, 2918, 2926, 2927, 2951, 2976, 2999, 3201, 3249, 3250, 3298, 3339, 3517
The MAXI/GSC auto-detection alert system independently detected
a new transient source at a position (R.A., Dec) = (+254.79 deg, -15.27 deg)
= (16h59m10s, -15d16m05s) (J2000) with a typical systematic uncertainty of 0.2 deg,
consistent with GRB 100925A detected by Swift/BAT (Mangano et al. GCN #11296).
MAXI/GSC data, however, suggests that the source has brightened
since around 2010-09-25 02:30, and almost linearly increased.
The 2-10 keV flux was 20+-8 mCrab during a transit around
2010-09-25 05:33 (UT), 19+-8 mCrab (07:04), 30+-9 mCrab (08:36), and
43+-9 mCrab (10:08). The latest (11:39) data show the flux is about 52 mCrab.
Note that Swift/BAT triggered the source at 2010-09-25 08:05:05.
These data show that the source is not a simple GRB as speculated by
Kann (GCN #11299), but a galactic X-ray transient. Further
followup observations are strongly encouraged.
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