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GCN Circular 18685

GRB 151212A: MAXI/GSC detection
2015-12-12T15:47:28Z (9 years ago)
Satoshi Nakahira at JAXA/MAXI <>
S. Nakahira(JAXA), H. Negoro (Nihon U.),
S. Ueno, H. Tomida, M. Ishikawa, Y. E. Nakagawa (JAXA),
T. Mihara, M. Sugizaki, M. Serino, M. Shidatsu, J. Sugimoto, T. Takagi, 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.),
Y. Tsuboi, S. Kanetou, Y. Nakamura, R. Sasaki (Chuo U.),
M. Yamauchi, D. Itoh (Miyazaki U.),
K. Yamaoka (Nagoya U.),
M. Morii (ISM)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient
source at UT 2015-12-12T14:00:27.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (68.109 deg, -3.775 deg) = (04 32 26, -03 46 30) (J2000)
with statistical uncertainties of ~0.5 degree.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).

The source showed a relatively soft energy spectrum, and a simple power-law fit gives a photon
index of 2.25 and the X-ray flux over the scan was 60 +- 12 mCrab (2-10keV, 1 sigma error).

There was no significant excess flux in the previous transit at UT 12:27
and in the next transit at 15:34 with an upper limit of 20 mCrab for each.

Detection Information:
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