[vsnet-grb-info 14568] GRB 140219A: MAXI/GSC detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15882
SUBJECT: GRB 140219A: MAXI/GSC detection
DATE:    14/02/26 03:08:11 GMT
FROM:    Motoko Suzuki at RIKEN  <motoko at crab.riken.jp>

M. Serino (RIKEN), S. Ueno, H. Tomida, S. Nakahira, 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, R. Usui, T. Yoshii, Y. Tachibana (Tokyo Tech), 
A. Yoshida, T. Sakamoto, Y. Nakano, Y. Kawakubo, H. Ohtsuki (AGU), 
H. Tsunemi, M. Sasaki (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 (Miyazaki U.), K. Yamaoka (Nagoya U.) 
report on behalf of the MAXI team:

The MAXI/GSC detected a rapid increase of the count rate in
all six working counters at 2014-02-19T19:45:58.15 UT.
The time is consistent with GRB 140219A 
(Hurley et al., GCN 15864; Zhang, GCN 15866; Guiriec et al., GCN 15867;
Golenetskii et al., GCN 15870).
The IPN postion of GRB 140219A was not in the field of view of any of the 
MAXI Gas Slit Cameras, implying that the detected counts are produced by the 
hard X-rays that penetrated the Ti counter walls with Pb shiled, or the phosphor 
bronze collimator with Al housing of GSC, or by the Compton-scattered electrons 
induced by the gamma-rays. It suggests that this GRB was exceptionally bright 
and hard.

The light curve shows an intense spike with a duration of ~0.2 s followed by
a bright emission until T0+~2.5 s. A weak emission lasts until T0+~20 s.
The peak count rate is ~2000 c/s per counter (GSC_3).
The MAXI/GSC light curve of this GRB is available at
http://maxi.riken.jp/news/en/?p=1101 .

There was no significant excess flux in the transits before and after the
GRB at UT 19:40 and 21:13 with an upper limit of 20 mCrab (4-10 keV, 1 sigma)
for each.

-- 
Motoko SERINO <motoko at crab.riken.jp>