[vsnet-grb-info 16920] GRB 150824A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  18201
SUBJECT: GRB 150824A: Fermi GBM detection
DATE:    15/08/24 16:04:33 GMT
FROM:    Elisabetta Bissaldi at U.Innsbruk/IAPP  <Elisabetta.Bissaldi at uibk.ac.at>

E. Bissaldi (INFN Bari) and E. Burns (UAH)
report on behalf of the Fermi GBM Team:


"At 01:53:31.76 UT on 24 August 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 150824A (trigger 462074015 / 150824079).

The on-ground calculated location, using the GBM trigger
data, is

RA = 161.3
DEC = -55.9

(J2000 degrees, equivalent to 10h 45m, -55d 55'),
with an uncertainty of 1.0 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 74 degrees.

The GBM light curve consists of several peaks
with a duration (T90) of about 13 s (50-300 keV).
The time-averaged spectrum from T0 to T0+15 s is
best fit by a Band function with Epeak = 187 +/- 9 keV,
alpha = -0.77 +/- 0.03, and beta = -2.40 +/- 0.10.

The event fluence (10-1000 keV) in this time interval is
(2.03 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1 s in the 10-1000 keV band
is 22.2 +/- 0.5 ph/s/cm^2.

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