[vsnet-grb-info 23839] GRB 191001A: Fermi GBM observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  25938
SUBJECT: GRB 191001A: Fermi GBM observation
DATE:    19/10/03 17:42:48 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007 at uah.edu>

E. Bissaldi (Politecnico & INFN Bari), R. Hamburg (UAH)
and C. Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 06:41:50.58 UT on 1 October 2019, the Fermi Gamma-Ray
Burst Monitor (GBM) triggered and located GRB 191001A
(trigger 591604915 / 191001279). The on-ground calculated
location has been reported in GCN #25893, and an IPN
annulus consistent with the GBM localization was reported
in GCN #25926. The ATLAS and DDOTI (GCN #25911) optical
counterpart position are consistent with the GBM localization.

The GBM light curve consists of several pulses
with a duration (T90) of about 24 s (50-300 keV).
The time-averaged spectrum from T0-4.99 s to T0+25.73 s
is best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.8 +/- 0.1
and the cutoff energy, parameterized as Epeak, is 114 +/- 9 keV.

The event fluence (10-1000 keV) in this time interval is
(4.7 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+15.7 s in the 10-1000 keV band
is 10.5 +/- 0.4 ph/s/cm^2.

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/"