GCN Circular 10714
Subject
GRB 100503A: Fermi GBM detection
Date
2010-05-04T21:01:06Z (15 years ago)
From
David Tierney at UCD <david.tierney@ucd.ie>
Dave Tierney (UCD) and Sheila McBreen (UCD/MPE)
report on behalf of the Fermi GBM Team:
"At 13:18:03.89 UT on 03 May 2010, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 100503A (trigger 294585485 / 100503554).
The on-ground calculated location, using the GBM trigger
data, is RA = 147.5, DEC = 4.0 (J2000 degrees,
equivalent to 09 h 50 m, 4 d 0 '), with an uncertainty
of 1.5 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 63 degrees.
The GBM light curve consists of multiple peaks
with a duration (T90) of 129.5 +/- 9.9 s (50-300 keV).
The time-averaged spectrum from T0-4 s to T0+52 s is
best fit by a power law function with an exponential
high energy cutoff. The power law index is -0.99 (+0.06/-0.05)
and the cutoff energy, parameterized as Epeak,
is 211.60 (+18.30/-15.50) keV (Cstat 877 for 601 d.o.f.).
The event fluence (10-1000 keV) in this time interval is
(1.23 +/- 0.03)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+46.5 s in the 10-1000 keV band
is 5.8 +/- 0.2 ph/s/cm^2.
A Band function fits the spectrum equally well
(Cstat 871 for 600 d.o.f.) with Epeak= 162.60 (+21.60/-17.00) keV,
alpha = -0.85 (+0.09/-0.09) and beta = -2.24 (+0.13/-0.21).
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."