[vsnet-grb-info 18899] GRB 170101B: Fermi GBM detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20350
SUBJECT: GRB 170101B: Fermi GBM detection
DATE:    17/01/01 10:24:47 GMT
FROM:    Andreas von Kienlin at MPE  <azk at mpe.mpg.de>

P Veres (UAH) and C Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 02:47:17.87 UT on 01 January 2017, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 170101B (trigger 504931642 / 170101116).

The on-ground calculated location, using the GBM trigger
data, is RA = 70.6, DEC = -1.6 (J2000 degrees,
equivalent to 04 h 43 m, -1 d 35 '), with an uncertainty
of 1.2 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 angle from the Fermi LAT boresight at the GBM trigger time is 65 degrees.

The GBM light curve shows/consists of two overlapping pulses
with a duration (T90) of about 12.8 s (50-300 keV).
The time-averaged spectrum from T0 to T0 + 15.7 s is
best fit by a Band function with Epeak = 213 +/- 13 keV,
alpha = -0.57 +/- 0.05, and beta = -2.29 +/- 0.12.

The event fluence (10-1000 keV) in this time interval is
(1.26 +/- 0.03)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 + 6.1 s in the 10-1000 keV band
is 7.0 +/- 0.3 ph/s/cm^2.

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