[vsnet-grb-info 20862] GRB 180718A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22960
SUBJECT: GRB 180718A: Fermi GBM detection
DATE:    18/07/19 03:53:43 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007 at uah.edu>

R. Hamburg (UAH), P. Veres (UAH), and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 01:57:44.60 UT on 18 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180718A (trigger 553571869 / 180718082),
which was also detected by the INTEGRAL SPI-ACS and subsequently
localized by IPN. Ground analysis of the Swift/BAT data revealed
a detection consistent with the IPN annulus (GCN 22959).

The angle from the Fermi LAT boresight at the GBM trigger time is 61
degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 0.08 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+0.02 s is
adequately fit by a Band function with Epeak = 187 +/- 61 keV,
alpha = -0.2 +/- 0.4, and beta = -2.3 +/- 0.5.

The event fluence (10-1000 keV) in this time interval is
(2.3 +/- 0.3)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-0.05 s in the 10-1000 keV band
is 9 +/- 1 ph/s/cm^2.

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