[vsnet-grb-info 14349] GRB 140102A: MAXI/GSC detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15663
SUBJECT: GRB 140102A: MAXI/GSC detection
DATE:    14/01/03 14:11:53 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

M. Kimura (JAXA), T. Sakamoto (AGU), S. Nakahira (JAXA), 
S. Ueno, H. Tomida, M. Ishikawa, 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, K. Ishikawa, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, Y. Nakano, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, M. Sasaki, D. Uchida (Osaka U.), 
H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, K. Suzuki (Nihon U.),
Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.), 
Y. Tsuboi, M. Higa (Chuo U.), 
M. Yamauchi, K. Yoshidome, Y. Ogawa, H. Yamada, Y. Morooka (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 21:19:54 UT on 2014-01-02.  Assuming that 
the source flux was constant over the transit, we obtain the source position at 

(R.A., Dec) = (211.813 deg, 1.477 deg) = (14 07 15, +01 28 37) (J2000) 

with a statistical 90% C.L. elliptical error region in long and short radii of 
0.46 deg and 0.35 deg respectively.  The roll angle of long axis from the north 
direction is 40.0 deg counterclockwise.  There is an additional systematic 
uncertainty of 0.1 deg (90% containment radius).  This uncatalogued X-ray 
source is temporary and positionally coincident with the Swift detected 
GRB 140102A (Hagen et al. GCN #15653).   

Using the data available from 21:16 to 21:23 UT, the MAXI/GSC spectrum 
is created from T0(BAT)+58.2 sec to T0(BAT)+219.2 sec (T0(BAT) is the trigger 
time of the Swift/BAT).  An absorbed power-law model gives an acceptable 
fit to the data.  The best fit photon index is 2.7 (-0.8/+1.0).  The unabsorbed 
2-20 keV flux is 2.3 (-0.8/+0.9) x 10^-9 erg/cm2/s.  All the quoted errors 
are at the 90% confidence level. 

There was no significant excess flux in the previous transit at 
19:47 UT and in the next transit at 22:53 UT with an upper limit 
of ~20 mCrab for each.