[vsnet-grb-info 4952] GRB 070734B: Analysis of AGILE gamma-ray data

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  6670
SUBJECT: GRB 070734B: Analysis of AGILE gamma-ray data
DATE:    07/07/26 15:31:47 GMT
FROM:    Sandro Mereghetti at IASF/CNR  <sandro at iasf-milano.inaf.it>

A.Chen, S.Vercellone, A.Giuliani, A.Pellizzoni, F.Fornari, S.Mereghetti, 
F.Perotti, M.Fiorini, P.Caraveo (IASF-Milano), C.Labanti, M.Marisaldi, 
F.Fuschino, M.Galli, A.Bulgarelli, F.Gianotti, M.Trifoglio, G.Di Cocco 
(IASF-Bologna), M.Tavani, G.Pucella, F.D'Ammando, E.Costa, M.Feroci, 
A.Trois, A.Argan (IASF-Roma), G.Picozza (INFN-Roma), F.Longo, 
G.Barbiellini (INFN-Trieste) on behalf of the AGILE Team

and  

C. Pittori, P.Giommi, L.A.Antonelli (ASDC), and L. Salotti (ASI) report:


Further analysis of the AGILE GRID (Gamma-Ray Imaging Detector) data of 
GRB 070724B (Feroci et al. GCN 6668) confirms the absence of significant 
emission at energy above 50 MeV. Only one photon consistent with the 
direction of GRB 070724B has been detected by the GRID in a ~100 second 
interval around the time of the burst. This is consistent with the 
measured background rate.

We note that a gamma-ray flux similar to that observed with EGRET from 
GRB930131 (Sommer et al.1994, ApJ 422, L66), would have given about 20 
counts in the GRID in the same time interval.

We also analyzed the data of the AGILE Mini-Calorimeter, which provides a 
nearly whole-sky monitor in the energy range ~0.35-3 MeV (no directional 
information), without finding any statistically significant count rate 
increase in correspondence of GRB 070724B.