[vsnet-grb-info 19118] GRB 170208C: POLAR Observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20664
SUBJECT: GRB 170208C: POLAR Observation
DATE:    17/02/12 01:08:15 GMT
FROM:    Zhao Yi at POLAR  <yizhao at ihep.ac.cn>

Yi Zhao (IHEP), Yuanhao Wang (IHEP), Hancheng Li (IHEP)
report on behalf of the POLAR collaboration:


At 2017-02-08T13:16:33.00 UT (T0), during a routine on-ground 
search of data, POLAR detected the GRB 170208C, 
which was also detected by the 
Fermi/GBM (trigger 508252598/170208553)
and INTEGRAL/SPIACS (trigger 7684).


The POLAR light curve consists of multiple peaks,
with a duration (T90) of 47.87 s measured from T0+2.15 s.
The 1-s peak rate measured from T0+47.00 s is 1842.1 cnts/s.
The total counts is about 20354 cnts. The above measurements
are in the energy range of about 20-500 keV.


LC_URL:
http://polar.ihep.ac.cn/grb/2017/02/GRB170208C/lc/POLAR_lc_grb170208C.png


Using the best location from the Fermi/GBM, which is (J2000):
RA:     284.420   [deg]
Dec:    -0.110    [deg]
Err:    2.52      [deg]


the incident angle in POLAR coordinate at T0 is:
theta:  93.2      [deg]
phi:    -50.0     [deg]


All analysis results presented above are preliminary.


POLAR is a dedicated Gamma-Ray Burst polarimeter (50-500 keV)
on-board the Chinese space laboratory Tiangong-2 launched on
Sep 15,2016. More information about POLAR can be found at 
http://polar.ihep.ac.cn/en/ , http://isdc.unige.ch/polar/
and http://polar.psi.ch/pub/.