GCN Circular 13776

Subject

Corrections to the Fermi-LAT upper limits for GRB 120807A, 120908A, 120909A, and 120911A

Date

2012-09-17T21:22:46Z (11 years ago)

From

Weikang Zheng at U.of Michigan <zwk@umich.edu>

Weikang Zheng and Carl Akerlof (Umich), report on behalf of the ROTSE
collaboration (the authors are not affiliated with the Fermi Collaboration),

The recent GCN Circulars we reported about Fermi-LAT upper limits for
GRB 120807A (GCN 13608), 120908A (GCN 13742), 120909A (GCN 13742), and
120911A (GCN 13752) contain an error about the upper limits estimation
due to a wrong method. We apologize for the confusion. We thank Giacomo
Vianello from LAT group for pointing it out and making suggestion to
correct it. We've updated our pipeline result with the appropriate
method (see The Fermi LAT team, Ackermann et al., 2012, ApJ, 754, 121).
We report the corrected upper limit result (100 MeV -300 GeV; T0-T0
+47.5s) for the 4 GRBs again:

GRB 120807A : 5.42e-05 ph/cm2/s
GRB 120908A : 1.79e-04 ph/cm2/s
GRB 120909A : 8.70e-05 ph/cm2/s
GRB 120911A : 3.81e-05 ph/cm2/s