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GCN Circular 13608

GRB 120807A: Fermi/LAT upper limit
2012-08-07T22:00:53Z (12 years ago)
Weikang Zheng at U.of Michigan <>
Weikang Zheng and Carl Akerlof (Umich), report on behalf of the ROTSE

We analyzed Fermi/LAT data of GRB 120807A (Marshall et al., GCN 13602)
as a follow-up of routine search in Swift trigger catalogs in our LAT
data processing pipeline using both the matched filter technique
(Akerlof et al. 2010, ApJ, 725, L15; 2011 ApJ, 726, 22; 2012,
arXiv:1205.3066; Zheng et al. 2012, ApJ 745,72; 2012, arXiv:1203.5113)
and likelihood method. We do NOT detect high energy photon emission from
both methods by using a standard data selection (with Energy above 100
MeV) in 47.5s duration.

The burst location was about 50 degree from the LAT boresight, and the
zenith angle was about 96 degrees at trigger time. This location is very
close to Galactic plane (gb = 333.3 and gb= 3.6 degree).

Using the likelihood method, we estimated the upper limit in LAT energy
range (0.1 - 10 GeV) is 1.27e-05 (photons cm^-2 s^-1) by assuming a
spectral index of -2.2.

The pipeline result is given in the following link:
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