[vsnet-grb-info 16063] GRB 150123A: MAXI/GSC detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17345
SUBJECT: GRB 150123A: MAXI/GSC detection
DATE:    15/01/23 16:38:25 GMT
FROM:    Motoko Suzuki at RIKEN  <motoko at crab.riken.jp>

K. Fukushima, H. Negoro (Nihon U.), M. Serino (RIKEN), S. Nakahira (JAXA),
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, H. Ohtsuki (AGU),
H. Tsunemi, D. Uchida (Osaka U.),
M. Nakajima, T. Onodera, K. Suzuki, T. Namba, M. Fujita, F. Honda (Nihon U.),
Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.),
Y. Tsuboi, A. Kawagoe (Chuo U.),
M. Yamauchi, Y. Morooka, D. Itoh (Miyazaki U.),
K. Yamaoka (Nagoya U.)
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source at 15:01:50 UT .
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (111.560 deg, -9.691 deg) = (07 26 14, -09 41 27) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.14 deg and 0.13 deg respectively.
The roll angle of long axis from the north direction is 110.0 deg counterclockwise.
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 332 +- 36 mCrab
(4-10keV, 1 sigma error).
There was no significant excess flux in the previous transit at UT 13:29
and in the next transit at 16:34 UT with an upper limit of 20 mCrab
for each.