WeiKang Zheng, Carl W. Akerlof, Shashi B. Pandey, Timothy A. McKay, BinBin Zhang, Bing Zhang
Since the launch of the Fermi gamma - ray Space Telescope on June 11, 2008,
the LAT instrument has solidly detected more than 20 GRBs with high energy
photon emission above 100 MeV. Using the matched filter technique, 3 more GRBs
have also shown evidence of correlation with high energy photon emission as
demonstrated by Akerlof et al. In this paper, we present another GRB
unambiguously detected by the matched filter technique, GRB 081006A. This event
is associated with more than 13 high energy photons above 100 MeV. The
likelihood analysis code provided by the $Fermi$ Science Support Center (FSSC)
generated an independent verification of this detection by comparison of the
Test Statistics (TS) value with similar calculations for random LAT data
fields. We have performed detailed temporal and spectral analysis of photons
from 8 keV up to 0.8 GeV from the GBM and the LAT. The properties of GRB
081006A can be compared to the other two long duration GRBs detected at similar
significance, GRB 080825C and GRB 090217A. We find that GRB 081006A is more
similar to GRB 080825C with comparable appearances of late high energy photon
emission. As demonstrated previously, there appears to be a surprising dearth
of faint LAT GRBs, with only one additional GRB identified in a sample of 74
GRBs. In this unique period when both $Swift$ and $Fermi$ are operational,
there is some urgency to explore this aspect of GRBs as fully as possible.
View original:
http://arxiv.org/abs/1201.3844
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