[vsnet-grb-info 19227] GRB 170318B: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20913
SUBJECT: GRB 170318B: Fermi GBM observation
DATE:    17/03/18 20:28:15 GMT
FROM:    Peter Veres at UAH  <veresp at gmail.com>

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

"At 15:27:53.09 UT on 18 March 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170318B (trigger 511543678 / 170318644).
which was also detected by the Swift/BAT
(Cholden-Brown et al. 2008, GCN 20908)
The GBM on-ground location is consistent with the Swift position.


The angle from the Fermi LAT boresight at the GBM trigger time is 93 degrees.


The GBM light curve shows  a single peak
with a duration (T90) of about 4 s (50-300 keV).
The time-averaged spectrum from T0-3.3 s to T0+1.8 s is
adequately fit by a simple power law function with index -1.40 +/- 0.10.


The event fluence (10-1000 keV) in this time interval is
(8.0 +/- 1.4)E-7 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.8 s in the 10-1000 keV band
is 1.9 +/- 0.2 ph/s/cm^2.


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