[vsnet-grb-info 19129] GRB 170214A: Fermi-LAT detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20676
SUBJECT: GRB 170214A: Fermi-LAT detection
DATE:    17/02/15 00:13:48 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin at nasa.gov>

J. L. Racusin (NASA/GSFC), G. Vianello (Stanford), and J. Perkins (NASA/GSFC), 
report on behalf of the Fermi-LAT team:

At 15:34:26.92 on February 14, 2017, Fermi-LAT detected high-energy 
emission from GRB 170214A, which was also detected by Fermi-GBM 
(trigger 508779271 / 170214649, Mailyan et al., GCN 20675). 

The best LAT on-ground location is found to be
RA, Dec:  256.33, -1.88 (degrees, J2000)
with an error radius of 0.08 deg (90% containment, statistical error only). 

This was 33 deg from the LAT boresight at the time of the trigger, and 
triggered an autonomous repoint of the spacecraft.

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.  More than 160 photons above 100 MeV and more than 13 
photons above 1 GeV are observed within 1000 seconds. The highest-
energy photon is a 7.8 GeV event which is observed ~105 seconds after 
the GBM trigger.

A Swift ToO has been approved for this burst.

The Fermi-LAT point of contact for this burst is 
Judith Racusin (judith.racusin 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.