[vsnet-grb-info 20960] GRB 180703B: CALET CAL gamma-ray analysis

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23058
SUBJECT: GRB 180703B: CALET CAL gamma-ray analysis
DATE:    18/07/30 09:44:28 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto at phys.aoyama.ac.jp>

K. Yoshikawa, Y. Asaoka (Waseda U), N. Cannady (LSU),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

Using the CALET CALorimeter (CAL) data, we report GeV gamma-ray search
analysis associated to GRB 180703B (Racusin et al. GCN Circ. 22884;
Takahashi et al. GCN Circ. 22888; Poolakkil and Meegan GCN Circ. 22897;
Hurley et al. GCN Circ. 22908; Frederiks et al. GCN Circ. 22914).

The CAL was operating in low energy trigger mode at the trigger time of
the CALET Gamma-ray Burst Monitor (CGBM).  We have searched for
gamma-ray events in the 1-10 GeV band from -60 sec to +60 sec from
the CGBM trigger time using the Fermi-LAT position (Racusin et al.
GCN Circ. 22884) and found no candidates.  The 90% upper limit of CAL is
1.5e-6 erg/cm2/s (1-10 GeV) assuming a power-law spectrum of a photon
index of -2.

All the quoted values are preliminary.