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GCN Circular 17805

GRB 150510A: Fermi-LAT detection
2015-05-10T09:22:55Z (9 years ago)
Giacomo Vianello at SLAC <>
G. Vianello (Stanford), J. Racusin (GSFC)

report on behalf of the Fermi-LAT team:

At  03:19:53.74 on May 10, 2015, Fermi-LAT detected high-energy emission
from GRB 150510A, which was also detected by Fermi-GBM (trigger 452920796/

The best LAT on-ground location is found to be

RA, Dec = 15.138,  4.985 (J2000)

with an error radius of 1.3 deg (90% containment, statistical error
only). This was 55 deg from the LAT boresight at the time of the trigger.

Our localization has an unusually large error because so far we have
received only 60 s worth of data after the trigger. Further contacts with
the spacecraft are scheduled for the next hours. We will release another
circular if the new data will allow us to refine the localization.

Our current localization is based on 5 photons between 100 and 300 MeV,
detected within 60 seconds from the trigger time.

Due to the large localization error, a Swift ToO has not been requested.

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

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.
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