[vsnet-grb-info 23901] GRB 191011A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  26000
SUBJECT: GRB 191011A: Fermi GBM observation
DATE:    19/10/11 14:23:34 GMT
FROM:    Peter Veres at UAH  <veresp at gmail.com>

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

"At 04:35:58.58 UT on 11 October 2019, the Fermi Gamma-Ray Burst Monitor
(GBM) triggered and located GRB 191011A (trigger 592461363 / 191011192), which
was also detected by the Swift/BAT (Laha et al. 2019, GCN 25988).

The GBM localization statistic exhibited two minima, one of which is
consistent with the Swift location (75% containment).  The localization
centroid in the Real-time Localization notice (GCN 25987) is for the other
minimum, which is near the Earth limb and is inconsistent with the Swift
location.

The angle from the Fermi LAT boresight at the GBM trigger time is 39
degrees.

The GBM light curve shows several pulses
with a duration (T90) of about 13 s (50-300 keV).
The time-averaged spectrum from T0-2.0 s to T0-0.38 s is
adequately fit by a simple power law function with index -1.76 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(4.33 +/- 0.50)E-7 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-1.8 s in the 10-1000 keV band is 3.29 +/- 0.30 ph/s/cm^2.

A power law function with an exponential high-energy cutoff
fits the spectrum equally well. The power law index is -1.24 +/- 0.29 and
the cutoff energy, parameterized as Epeak, is 89 +/- 23 keV.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support
Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"