[vsnet-grb-info 21449] GRB 181222A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23548
SUBJECT: GRB 181222A: Fermi GBM observation
DATE:    18/12/22 17:37:52 GMT
FROM:    Peter Veres at UAH  <veresp at gmail.com>

P. Veres (UAH) and E. Bissaldi (Politecnico & INFN Bari)
report on behalf of the Fermi GBM Team:

"At 06:41:34.25 UT on 22 December 2018, the Fermi Gamma-Ray Burst
Monitor triggered
and located GRB 181222A (trigger 567153699 / 181222279) which was also
detected by MAXI/GSC
(Sakamaki et al., GCN 23547). The GBM on-ground location is consistent with
the MAXI position.


The angle from the Fermi LAT boresight at the GBM trigger time is 89
degrees.


The GBM light curve shows four separate pulses
with a duration (T90) of about 131 s (50-300 keV).
The time-averaged spectrum from T0-1 s to T0+151 s is
adequately fit by a Band function with Epeak = 264 +/- 32 keV,
alpha = -0.95 +/- 0.04, and beta = -1.47 +/- 0.01.

The event fluence (10-1000 keV) in this time interval is
(1.83 +/- 0.01)E-4 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+94.9 s in the 10-1000 keV band
is 74.7 +/- 0.7 ph/s/cm^2.


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