[vsnet-grb-info 7983] GRB 090618: AGILE observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  9524
SUBJECT: GRB 090618: AGILE observations
DATE:    09/06/18 15:21:44 GMT
FROM:    Marco Feroci at IASF/INAF  <feroci at iasf-roma.inaf.it>

F. Longo, E. Moretti, G. Barbiellini, E. Vallazza (INFN Trieste),
M.Trifoglio, A. Bulgarelli, F. Gianotti F. Fuschino, M. Marisaldi,
C.Labanti, M.Galli, G.DiCocco (INAF/IASF Bologna), S. Cutini, C.
Pittori (ASDC), M.Tavani, E.Striani, G. Pucella, F. D'Ammando, 
V.Vittorini, A. Argan, A. Trois, G. Piano, S. Sabatini
(INAF/IASF Rome), E. Del Monte, M. Feroci, Y. Evangelista, I. Donnarumma,
L. Pacciani, P. Soffitta, E. Costa, F.Lazzarotto, I. Lapshov, M. Rapisarda
(INAF/IASF Rome) A. Giuliani, A. Chen, S. Mereghetti, F. Perotti, P.
Caraveo (INAF/IASF Milano), A. Pellizzoni, M. Pilia (INAF/OA Cagliari), S. 
Vercellone (INAF/IASF Palermo), P. Picozza, A. Morselli (INFN Roma-2), M. 
Prest (Universita` dell'Insubria), P. Lipari, D. Zanello (INFN Roma-1), A. 
Rappoldi, P. Cattaneo (INFN Pavia) and P. Giommi, P. Santolamazza, F. 
Verrecchia (ASDC) and L. Salotti (ASI), on behalf of the AGILE Team, 
report:


The AGILE satellite detected GRB 090618 (P. Schady et al. GCN #9512)
at about 36 degrees off axis.
 
Super-AGILE, operating in the 18-60 keV energy range, triggered and 
localized the burst in the 1-D region of the field of view at a position
consistent with the Swift/BAT localization. The emission from this bright 
GRB with a complex lightcurve was detected at high significance despite 
the large off-axis direction.

AGILE-MCAL, operating in the 350 keV - 100 MeV energy range, triggered
this GRB at 08:28:24.772 UT (T0).  The MCAL overall burst duration is
about 100 sec. The burst is composed by three main pulses, the
brightest starting at T0+62sec and lasting about 14 seconds.
The total MCAL spectrum between T0 and T0+120 sec can be fit by a
simple powerlaw with photon index 3.16 (-0.30, +0.39) (90% c.l.),
with reduced chi^2 0.99 (9 d.o.f.), in the 0.5-10 MeV energy range.
The estimated fluence is (3.2 +/- 0.6) 10^{-5} erg cm^-2 in the same
energy range.