GCN Circular 20616
Subject
GRB 170206A: Fermi GBM observation
Date
2017-02-06T18:04:50Z (8 years ago)
From
Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>
A. von Kienlin (MPE) and O.J. Roberts (USRA/NASA-MSFC) report
on behalf of the Fermi GBM Team:
"At 10:51:57.70 UT on February 6th 2017, the Fermi Gamma-Ray
Burst Monitor triggered and located GRB 170206A
(trigger 508071122 /170206453). The on-ground calculated
location, using the GBM trigger data,
is RA = 211.80, DEC = +13.06, (J2000 degrees, equivalent to
J2000 14h 07m, +/- 13d 03')
with an uncertainty of 1.14 degrees (radius, 1-sigma
containment, statistical only; there is additionally a
systematic error which we have characterized as a
core-plus-tail model, with 90% of GRBs having a 3.7 deg.
error and a small tail suffering a larger than 10 deg.
systematic error. [Connaughton et al. 2015, ApJS, 216, 32]).
The trigger resulted in an Autonomous Repoint Request (ARR)
by the GBM Flight Software owing to the high peak flux of the
GRB. This ARR was accepted and the spacecraft slewed to the
GBM in-flight location. The initial angle from the Fermi-LAT
boresight to the GBM ground location is 67 degrees.
The GBM light curve shows a short, bright burst with a duration
(T90) of about 1.2 s (50-300 keV). The time-averaged spectrum
from T0+0.1s to T0+1.3 s is best fit by a BAND function, with
alpha= -0.28 +/- 0.04, beta= -2.55 +/- 0.12 and Epeak,
is 341 +/- 13 keV.
The event fluence (10-1000 keV) in this time interval is
(1.34 +/- 0.02) E-05 erg/cm^2. The 64 ms peak photon flux
measured starting from T0+0.6 s in the 10-1000 keV band is
57.0 +/- 2.1 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."