[vsnet-grb-info 19026] GRB 170130A: POLAR Observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20568
SUBJECT: GRB 170130A: POLAR Observation
DATE:    17/02/01 08:43:20 GMT
FROM:    Radek Marcinkowski at PSI/POLAR  <radoslaw.marcinkowski at psi.ch>

R. Marcinkowski (PSI), H.L. Xiao (PSI) and W. Hajdas (PSI) report on behalf 
of the POLAR collaboration:

At 2017-01-30 07:14:45 UT(T0), during a routine on-ground search of data, 
POLAR detected GRB 170130A, which was also observed by Fermi GBM 
(trigger # 507453289). Significant detection was recorded in 9 of 25 POLAR 
modules.

The POLAR light curve consists of multi peak structure with duration (T90) 
of 35.0 +/- 1.0 s measured from T0 and is compatible with Fermi GBM light curve. 
The 1.0 s peak flux at T0 + 30.5 s is equal to 480 +/- 80 counts/sec. POLAR 
recorded about 5300 events from the burst.

Above measurements are in the energy range of about 20 - 500 keV and bases 
on data from 9 modules.

LC_URL: http://polar.psi.ch/triggers/GRB_170130A_raw_9of25.png
     or http://polar.psi.ch/pub/lc.php?event=GRB+170130A

Using the best location from Fermi GBM, which is (J2000):
RA : 271.1 [deg]
Dec: -29.1 [deg]
Err:   5.5 [deg]

the incident angle in the POLAR coordinate at T0 is:
Theta: 56.2 [deg]
Phi:  230.9 [deg]

The analysis results presented above are preliminary. Calibration of the 
instrument is ongoing. POLAR is a dedicated Gamma-Ray Burst polarimeter 
which was launched on-board the Chinese space laboratory Tiangong-2 (TG-2) 
on Sep 15, 2016. The energy detection range of POLAR is ~ 50-500 keV.
More information about POLAR can be found at http://polar.psi.ch/pub , 
http://polar.ihep.ac.cn/en/ and http://isdc.unige.ch/polar/ .

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