[vsnet-grb-info 1909] GCN GRB observation 050713A

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  3747
SUBJECT: GCN GRB observation 050713A
DATE:    05/08/03 19:30:58 GMT
FROM:    Alessandro De Angelis at INFNandUdineU.  <deangeli at fisica.uniud.it>

TITLE:   GCN GRB OBSERVATION REPORT
SUBJECT: GRB 050713A:  Observation at very high energy by MAGIC

N. Galante and Stamerra (INFN/Siena)
D. Bastieri, M. Fagiolini, M. Gaug, M. Garczarczyk, T. Lenisa, F. Longo, 
K. Mannheim, S. Mizobuchi, A. Moralejo, R. Paoletti, L. Peruzzo, A Piccioli, S. Shore
on behalf of the MAGIC Collaboration:

"The MAGIC Cherenkov telescope in La Palma has observed GRB050713A 40s after T0. 
This observation, started 20 seconds after the alert given
by Swift (Trigger #145675; Falcone et al., GCN Circ 3581), thanks to the 
capability of fast pointing by MAGIC and to the prompt reaction by the operators; it
overlapped for around 30 seconds with Swift during the main burst, 
and lasted 2400 s. The first look at the MAGIC data did not reveal strong gamma ray 
emission above 175GeV. The flux limit derived at very 
high energies by MAGIC is 2-3 orders of magnitude lower than the extrapolation from
the X band [1]. A detailed analysis is in progress. To our knowledge, this is the first
simultaneous observation of a GRB in the X band and in the HE gamma region."

[1] A. Falcone, private communication.