[vsnet-grb-info 14982] GRB 140515B: MAXI/GSC detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  16276
SUBJECT: GRB 140515B: MAXI/GSC detection
DATE:    14/05/15 23:22:58 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

M. Morii (RIKEN), S. Ueno, H. Tomida, S. Nakahira, M. Kimura, M. Ishikawa, 
Y. E. Nakagawa (JAXA), T. Mihara, M. Sugizaki, 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.), H. Negoro, M. Nakajima, K. Fukushima, T. Onodera, 
K. Suzuki (Nihon U.), Y. Ueda, M. Shidatsu, T. Kawamuro, T. Hori (Kyoto U.),
Y. Tsuboi (Chuo U.), M. Yamauchi, 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 2014-05-15T13:00:53 UT.  Assuming that the source flux was constant 
over the transit, we obtain the source position at

(R.A., Dec) = (289.354 deg, -11.701 deg) = (19 17 24, -11 42 03) (J2000)

with a rectangular error box in the following corners:

(289.185 deg, -12.277 deg) = (19 16 44, -12 16 38) (J2000)
(288.651 deg, -11.941 deg) = (19 14 36, -11 56 28) (J2000)
(289.546 deg, -10.794 deg) = (19 18 11, -10 47 39) (J2000)
(290.074 deg, -11.136 deg) = (19 20 17, -11 08 10) (J2000).

There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 80 +- 18 mCrab (4-10keV, 1 sigma error).
There was no significant excess flux in the previous transit at UT 11:28
and in the next transit at 14:33 UT with an upper limit of 20 mCrab for each.