[vsnet-grb-info 13195] GRB 130502B: Fermi LAT Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14532
SUBJECT: GRB 130502B: Fermi LAT Detection
DATE:    13/05/02 21:50:17 GMT
FROM:    Daniel Kocevski at SLAC  <dankocevski at gmail.com>

GRB 130502B: Fermi-LAT detection of a burst

D. Kocevski (NASA/GSFC), G. Vianello (Stanford), J. Chiang (SLAC), J. Racusin (NASA/GSFC), and E. Troja (CRESST) report on behalf of the Fermi-LAT team:

At 07:51:11 UT on 2nd May 2013, Fermi-LAT detected high energy emission from GRB 130502B, which was also detected by Fermi-GBM (trigger 389173874/130502327) (GCN 14530) .

The best LAT on-ground location is found to be RA, DEC 66.648, 71.0841 (J2000) with an error radius of 0.093 deg (68% containment, statistical error only), this was about ~45 deg from the LAT boresight at the time of the trigger. The data from the Fermi-LAT show a multi-peaked light curve consistent with the GBM data. More than 100 photons above 100 MeV are observed within 200 seconds with a TS of > 158. The multi-peak structure is clearly seen in the non-standard LAT Low Energy (LLE) data selection, with a significance of ~8 sigma. The highest energy LAT photon consistent with the burst position has an energy of 30 GeV and arrived ~220s after the trigger.

A Swift TOO request has been submitted.

The Fermi LAT point of contact for this burst is Daniel Kocevski (daniel.kocevski at nasa.gov).

The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.