GRB 151210B

T. Sakamoto, A. Yoshida, I. Takahashi, Y. Kawakubo, K. Senuma, 
M. Moriyama, Y. Yamada (AGU), K. Yamaoka (Nagoya U), S. Nakahira (JAXA), 
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U), 
M. L. Cherry (LSU), S. Ricciarini (U of Florence), P. S. Marrocchesi (U of Siena) 
and the CALET collaboration:

The long-duration GRB 151210B (Fermi-GBM trigger #471401960) triggered the CALET 
Gamma-Ray Burst Monitor (CGBM) at 00:59:20.12 UT on 10 December 2015.  The burst 
was detected by all three CGBM instruments.  

The light curve of the Soft Gamma-ray Monitor (SGM; 30 keV - 20 MeV) shows the main 
peak starting from T0-3 sec, peaking at T0 and ending at T0+~40 sec.   
The T90 duration measured by the SGM data is 39 +- 3  sec (40-460 keV).  

Currently, CALET is in the commissioning phase.  Further information about CALET and 
CGBM can be found at http://calet.jp/en/ and http://www.en.yoshida-agu.net/research/calet-gbm

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

"At  00:59:16.643 UT on 10 December 2015, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 151210B (trigger 471401960 / 151210041)
which was also detected by the CALET Gamma-Ray Burst Monitor
(Sakamoto et al. 2015, GCN 18701
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 ).

The on-ground calculated location, using the GBM trigger
data, is RA = 294.0, DEC = -42.7 (J2000 degrees,
equivalent to 19 h 36 m, 42 d 42 '), with an uncertainty
of 3.4 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 13 degrees.


The GBM light curve shows an initial peak followed by a weaker emission episode
with a duration (T90) of about 37.6 s (50-300 keV).
The time-averaged spectrum from T0-4 s to T0+39 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.45 +/- 0.08 and
the cutoff energy, parameterized as Epeak, is 306 +/- 94 keV.

The event fluence (10-1000 keV) in this time interval is
(5.8 +/- 0.4)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.7 s in the 10-1000 keV band
is 2.4 +/- 0.2 ph/s/cm^2.


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