GCN Circular 12187
Subject
GRB 110721A: Fermi GBM detection
Date
2011-07-21T11:17:24Z (13 years ago)
From
David Tierney at UCD <david.tierney@ucd.ie>
D. Tierney (UCD) and A. von Kienlin (MPE)
report on behalf of the Fermi GBM Team:
"At 04:47:43.75 UT on 21 July 2011, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 110721A (trigger 332916465 / 110721200).
The on-ground calculated location, using the GBM trigger
data, is RA = 331.42, DEC = -36.42 (J2000 degrees,
equivalent to 22h 05m, -36d 25'), with an uncertainty
of 1.00 degree (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 43.00 degrees.
The GBM light curve consists of a fast rise, exponential decay (FRED)
with a duration (T90) of 24.45 s (50-300 keV).
The time-averaged spectrum from T0-0.32 s to T0+11.97 s is
best fit by a Band function with Epeak = 372.50 (+26.50/-23.60) keV,
alpha = -0.94 (+/-0.02), and beta = -1.77 (+/-0.02)
(C-Stat 945.78 for 591 d.o.f.).
The event fluence (10-1000 keV) in this time interval is
(3.52 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.98 s in the 10-1000 keV band
is 31.35 +/- 0.38 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."