[vsnet-grb-info 18026] GRB 160530B: Fermi GBM Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  19474
SUBJECT: GRB 160530B: Fermi GBM Detection
DATE:    16/05/31 00:38:22 GMT
FROM:    Bagrat Mailyan at UAH  <bm0054 at uah.edu>

B. Mailyan (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:

"At 16:01:11.83 UT on 30 May 2016, the Fermi Gamma-Ray
Burst Monitor triggered and located GRB 160530B
(trigger 486316875/160530667). The on-ground calculated location,
using the GBM trigger data, is RA =  133.48, DEC = 43.48, with an
uncertainty of 1.0 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 angle from the Fermi LAT boresight at the GBM
trigger time is 78 degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 9 s (50-300 keV).
The time-averaged spectrum from T0+2.8 s to T0+12.0 s is
best fit by a BAND function, with Epeak = 188.40 +/- 2.23  keV,
alpha = -0.56 +/- 0.01, and beta = -2.53 +/- 0.04.

The event fluence (10-1000 keV) in this time interval is
 (8.898 +/- 0.055)E-05 erg/cm^2. The 1-sec peak photon flux
measured starting from T0+5.6 s in the 10-1000 keV band
is 107.7 +/- 0.7 ph/s/cm^2.

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