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GCN Circular 14969

GRB 130628A: Fermi GBM detection
2013-07-03T11:40:30Z (11 years ago)
David Byrne at UCD <>
D. Byrne (UCD), C. Meegan (UAH) and M. Burgess (UAH) report on behalf
of the Fermi GBM Team:

"At 12:44:02.12  UT on 28 June 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130628A (trigger 394116245/130628531)

High peak flux from the GRB caused GBM to issue a repoint request
that reoriented the satellite to place the GRB near the LAT boresight
for 2.5 hours, subject to Earth limb contraints.

The on-ground calculated location, using the GBM trigger
data, is RA = 6.29, DEC = -5.07 (J2000 degrees,
equivalent to 00 h 25m, -5 d 0'), with an uncertainty
of 1.71 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which is currently estimated to be 2 to 3 degrees).
The angle from the Fermi LAT boresight is 67 degrees.

The GBM light curve consists of two pulses
with a duration (T90) of about 22 s (50-300 keV).
The time-averaged spectrum from T0-3.1 s to T0+25.6 s is
well fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.51 +/- 0.04 and
the cutoff energy, parameterized as Epeak, is 128 +/- 11 keV.

The event fluence (10-1000 keV) in this time interval is
(9.9 +/- 0.3)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.8 s in the 10-1000 keV band
is 14.5 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

David Byrne BSc.
School of Physics,
Science Center North,
University College Dublin,
Belfield, Dublin 4,
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