Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

GCN Circular 5789

GRB061028: MAGIC telescope GeV observation
2006-11-08T11:45:41Z (18 years ago)
Markus Garczarczyk at MPI/MAGIC <>
Gaug M. and Garczarczyk M., Bastieri D., Fagiolini M., Galante N.,
Longo F., Mizobuchi S., Piccioli A., Scapin V. and Stamerra A.
report for the MAGIC collaboration:

The MAGIC Imaging Atmospheric Cherenkov Telescope performed a follow-up
observation of the SWIFT-BAT burst GRB061028 (GCN circular 5762, Sakamoto
T. et al.). We received the GCN alert at T0+140s. The telescope slewed
immediately to the GRB sky coordinates and started data taking 29s after
the alert, at T0+169s. Due to the long time delay of the alert and the
burst duration of T90=106s, only the early afterglow phase could be
observed by MAGIC. Our observation window covered the weak tail emission
measured by BAT and the X-ray afterglow measured by XRT (Sakamoto T. et
al.). The observation continued for 100min.

No evidence for VHE gamma-ray emission above the analysis threshold of
110GeV was found. 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 (inc. 30%
systematic error on the absolute flux level):

E(100-125 GeV)  : 1.6 x 10^(-10) erg/cm^2/s
E(125-175 GeV)  : 0.8 x 10^(-10) erg/cm^2/s
E(175-300 GeV)  : 0.7 x 10^(-10) erg/cm^2/s
E(300-1000 GeV) : 0.3 x 10^(-10) erg/cm^2/s

The upper limits apply of the time window between T0+169s and T0+1969s
(the first 30min of the MAGIC data sample).

This message can be cited.
Looking for U.S. government information and services? Visit