[vsnet-grb-info 16785] GRB 150724B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18066
SUBJECT: GRB 150724B: Fermi GBM detection
DATE:    15/07/25 16:22:15 GMT
FROM:    Peter Veres at ELTE,Budapest  <veresp at gmail.com>

P. Veres (UAH), V. Connaughton (USRA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 18:45:37.714 UT on 24 July 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150724B (trigger 459456341 / 150724782)
which was also detected by the Fermi/LAT (Bissaldi et al. 2008, GCN
18065). The GBM on-ground location is consistent with the Fermi/LAT
position.


The on-ground calculated location, using the GBM trigger
data, is RA = 350.92, DEC = +10.160 (J2000 degrees,
equivalent to 23h 24m, 10d 10'), with an uncertainty
of 1.05 degrees (radius, 1-sigma containment,
statistical only).


The GBM light curve consists of two emission episodes
with a total duration (T90) of about 38 s (50-300 keV).
The time-averaged spectrum from T0-6.1 s to T0+46 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.75 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 729 +/- 35 keV.


The event fluence (10-1000 keV) in this time interval is
(3.55 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+40 s in the 8-1000 keV band is 8.3 +/- 0.2 ph/s/cm^2.


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