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GCN Circular 14674

GRB 130518A: Fermi GBM detection
2013-05-18T20:52:02Z (11 years ago)
Shaolin Xiong at UAH <>
Shaolin Xiong (UAH) reports on behalf of the Fermi GBM Team:

"At 13:54:37.53 UT on 18 May 2013, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 130518A (trigger 390578080 / 130518580).

High peak flux from the GRB caused GBM to issue a repoint request,
but the spacecraft did not slew to this burst due to the Solar TOO.

The on-ground calculated location, using the GBM trigger
data, is RA = 355.88, DEC = 46.05 (J2000 degrees,
equivalent to 23 h 43 m, 46 d 03 '), with an uncertainty
of 1 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 43 degrees.

The GBM light curve consists of several pulses
with a duration (T90) of about 48 s (50-300 keV).
The time-averaged spectrum from T0+10 s to T0+60 s is
adequately fit by a Band function with Epeak = 396 +/- 9 keV,
alpha = -0.86 +/- 0.01, and beta = -2.27 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is
(9.3 +/- 0.06)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+25.6 s in the 10-1000 keV band
is 45.4 +/- 0.4 ph/s/cm^2.

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