GCN Circular 7585
Subject
GRB080330: MAGIC telescope GeV observation
Date
2008-04-11T23:41:23Z (16 years ago)
From
Markus Garczarczyk at MPI/MAGIC <garcz@mppmu.mpg.de>
Gaug M., Garczarczyk M., Antonelli A., Bastieri D., Covino S., Galante N.,
La Barbera A., Longo F. and Scapin V. for the MAGIC collaboration
The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up
observation of the BAT burst GRB080330 (GCN circular 7537, Mao et al.).
We received the GCN alert at 03:41:33 UT (T0+16s), data taking with MAGIC
started at 03:42:47 UT (T0+91s), short after the prompt emission phase
measured to be T90=61+/-9s. The observation was carried out at a zenith
angle of 48 degrees. The observation continued for 1039s.
No evidence for VHE gamma-ray emission above the analysis threshold of
313 GeV was found. The observation was carried out in (less sensitive)
moon-observation mode.
A preliminary analysis, for the hypothesis of steady emission and
assumption of a differential photon spectral index of -2.5, yields the
following 95% CL differential flux upper limits, including a 30%
systematic uncertainty on the telescope efficiency:
E (175- 300 GeV): 0.36 * 10^-10 erg/cm^-2/s
E (300-1000 GeV): 0.49 * 10^-10 erg/cm^-2/s
for a time window from 03:42:47 UT to 03:59:01 UT
We can also exclude emission of a constant flux in any 100s time bin
smaller than:
E (175- 300 GeV): 8.42 * 10^-10 erg/cm^-2/s
E (300-1000 GeV): 2.05 * 10^-10 erg/cm^-2/s
for a time window from 03:42:47 UT to 03:59:01 UT
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