GCN Circular 20646
Subject
GRB 170208B: Fermi GBM Detection
Date
2017-02-09T15:19:35Z (7 years ago)
From
Oliver J Roberts at USRA/NASA <oliver.roberts@nasa.gov>
O.J. Roberts (USRA/NASA) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:
"At 22:33:36.53 UT on the 8th of February 2017,
the Fermi Gamma-Ray Burst Monitor triggered and
located GRB 170208B (trigger 508286021 / 170208940),
which was also detected by Konus-Wind
(Svinkin et al. 2017, GCN 20643) and Swift
(Siegel et al. 2017, GCN 20632). The GBM on-ground
location is consistent with the Swift position.
The angle from the Fermi LAT boresight at the GBM
trigger time using the Swift-XRT position is 54 degrees.
The GBM light curve consists of a long GRB with
overlapping episodes of bright emission over a
duration (T90) of about 22 s (50-300 keV). The
time-averaged spectrum from T0-8.0 s to T0+14.0 s is
adequately fit by a Band function with
Epeak = 104.1 +/- 5.5 keV, alpha = -0.83 +/- 0.05, and
beta = -2.33 +/- 0.09
The event fluence (10-1000 keV) in this time interval is
(1.13 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux
measured starting from T0-7.9 s in the 10-1000 keV band
is 12.1 +/- 0.3 ph/s/cm^2.
The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."