[vsnet-grb-info 16531] GRB 150513A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17812
SUBJECT: GRB 150513A: Fermi-LAT detection
DATE:    15/05/14 04:43:47 GMT
FROM:    Daniel Kocevski at GSFC  <daniel.kocevski at nasa.gov>

GRB 150513A: Fermi-LAT detection

D. Kocevski (NASA/GSFC), G. Vianello (Stanford), and M. Arimoto (Tokyo Tech),
report on behalf of the Fermi-LAT team:

At 20:33:15.25 on May 05, 2015, Fermi-LAT detected high-energy emission from GRB 150513A, which was also detected by Fermi-GBM (trigger 453241998) and Swift-BAT (Kocevski et al. 2015, GCN 17810).

The best LAT on-ground location is found to be

RA, Dec 49.2, -23.2 (J2000)

with an error radius of 0.4 deg (90% containment, statistical error only). This position was 50 deg from the LAT boresight at the time of the trigger and consistent with the position found by Swift-BAT.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The highest-energy event is a 2.1 GeV event detected at T0 + 60 s. The GRB was observable from T0 to T0 + 385 s, before the spacecraft entered the South Atlantic Anomaly, where data gathering is disabled.

The Fermi-LAT point of contact for this burst is Makoto Arimoto (arimoto at hp.phys.titech.ac.jp<mailto:arimoto at hp.phys.titech.ac.jp>).

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.