GCN Circular 20624
Subject
GRB 170206A: POLAR observation
Date
2017-02-07T21:13:46Z (7 years ago)
From
Yuanhao Wang at IHEP/CAS <wangyuanhao@ihep.ac.cn>
Yuanhao Wang (IHEP), Shaolin Xiong (IHEP), Yi Zhao (IHEP)
report on behalf of the POLAR collaboration:
At 2017-02-06T10:51:57.70 UT (T0), during a routine on-ground
search of data, POLAR detected the GRB 170206A, which was
also detected by Fermi/GBM
(trigger 508071122/170206453; A. von Kienlin et al. GCN 20616),
Fermi/LAT(F. Fana Dirirsa et al. GCN 20617) and
INTEGRAL/SPIACS(trigger_num 7680).
The POLAR light curve consists of multiple peaks,
with a duration (T90) of 1.194 s measured from T0+0.147 s.
The 0.1s peak rate measured from T0+0.4s is 16145.2 cnts/s.
The total counts is about 12918 cnts.
LC_URL:
http://polar.ihep.ac.cn/grb/2017/02/GRB170206A/lc/POLAR_lc_grb170206A.png
The above result is not dead time corrected. The above
measurements are in the energy range of about 20-500 keV.
Using the best location from the Fermi/LAT, which is (J2000):
RA: 212.79��[deg]
Dec: +14.48��[deg]
Err: 0.85����[deg] (90% containment, statistical error only)
the incident angle in POLAR coordinate at T0 is:
theta: 19.5 [deg]
phi: 148.70 [deg]
The Minimum Detectable Polarization(MDP) for this burst is
estimated to be ~5.7% [1-sigma, statistical only].
Follow-up observations are strongly encouraged.
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/ .