TITLE:   GCN CIRCULAR
NUMBER:  20559
SUBJECT: GRB 170124A: POLAR Observation
DATE:    17/01/28 12:40:29 GMT
FROM:    Zhao Yi at POLAR  <yizhao@ihep.ac.cn>

Yi Zhao (IHEP), R. Marcinkowski (PSI), Xing Wen (IHEP),
H. Xiao (PSI), Minzi Feng (IHEP) and W. Hajdas (PSI)
report on behalf of the POLAR collaboration:

At 2017-01-24T20:58:06.00 UT (T0), during a routine on-ground 
search of data, POLAR detected the GRB 170124A, 
which was also detected by the 
Fermi/GBM (trigger 506984291/170124873), Konus-Wind and 
the CALET Gamma-ray BurstMonitor (Circ 20556).

The POLAR light curve consists of multiple peaks,
with a duration (T90) of 22.38 s measured from T0+2.26 s.
The 1-s peak rate measured from T0+8.00 s is 514.8 cnts/s.
The total counts is about 7657 cnts. The above measurements
are in the energy range of about 80-500 keV.

LC_URL:
http://polar.ihep.ac.cn/grb/2017/01/GRB170124A/lc/POLAR_lc_grb170124A.png

Using the best location from the Fermi/GBM, which is (J2000):
RA:     282.040  [deg]
Dec:    -75.510  [deg]
Err:    1.00     [deg]

the incident angle in POLAR coordinate at T0 is:
theta:  111.4    [deg]
phi:    -143.2   [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/.