[vsnet-grb-info 20199] GRB 180102A: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  22295
SUBJECT: GRB 180102A: Fermi GBM detection
DATE:    18/01/02 20:38:51 GMT
FROM:    Peter Veres at UAH  <veresp at gmail.com>

P. Veres (UAH) reports on behalf of the Fermi GBM Team:

"At 15:49:47.21 UT on 2 January 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180102A (trigger 536600992 / 180102660) which
was also detected by Swift/BAT (Page et al., GCN 22292).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 60 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 16 s (50-300 keV).
The time-averaged spectrum from T0-6.1 s to T0+2.0 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.40 +/- 0.44 and
the cutoff energy, parameterized as Epeak, is 54.9 +/- 6.7 keV.

The event fluence (10-1000 keV) in this time interval is
(4.31 +/- 0.45)E-7 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.7 s in the 10-1000 keV band
is 1.76 +/- 0.19 ph/s/cm^2.

A Band function fits the spectrum equally well with Epeak= 41.8 +/- 9.2 keV,
 alpha = 0.59 +/- 1.18 and beta = 2.52 +/- 0.35.

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