[vsnet-grb-info 21559] GRB 190109A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  23658
SUBJECT: GRB 190109A: Fermi GBM observation
DATE:    19/01/09 16:56:02 GMT
FROM:    Andreas von Kienlin at MPE  <azk at mpe.mpg.de>

A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team:

"At 05:12:49.45 UT on 09 January 2019, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 190109A (trigger 568703574 / 190109217), which was
also detected by the Swift/BAT (Gropp et al. 2019, GCN 23642)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 65 degrees.

The GBM light curve shows a structured emission
with a duration (T90) of about 120 s (50-300 keV).
The time-averaged spectrum from T0-4.096 s to T0+114.690 s is
best fit by a Band function with Epeak = 46.8 +/- 2.2 keV, alpha = 1.3 +/- 0.3, 
and beta = -2.71 +/- 0.13 

The event fluence (10-1000 keV) in this time interval is
(7.6 +/-  0.4)E-06 erg/cm^2. The 1.024-sec peak photon flux measured
starting from T0+30.91 s in the 10-1000 keV band
is 2.6 +/- 0.2 ph/s/cm^2.

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