[vsnet-grb-info 19184] GRB 170306B: POLAR observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20839
SUBJECT: GRB 170306B: POLAR observation
DATE:    17/03/08 14:02:46 GMT
FROM:    Haulin Xiao at PSI/POLAR  <hualin.xiao at psi.ch>

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

At 2017-03-06 14:07:20.0 UT(T0), during a routine on-ground search of data, POLAR detected GRB 170306B,
which was also observed by  Fermi-GBM (trigger # 510502047), Fermi-LAT (trigger #170306588) and SPI ACS at 2017-03-06 14:07:25.

The POLAR light curve consists of multiple peaks with duration (T90) of 25.0 +/- 1.0 s measured from T0.
The 1.00 s peak flux at T0 + 11.50 s  is equal to 2380 +/- 100 counts/sec.
POLAR recorded 31640 events from the burst.
Above measurements are in the energy range of about 15 - 300 keV.

LC_URL: http://polar.psi.ch/triggers/GRB_170306B_raw.png
     or http://polar.psi.ch/pub/lc.php?event=GRB+170306B

Using the best location from Fermi-LAT, which is (J2000):
RA : 154.650 [deg]
Dec:  51.630 [deg]
Err:  39.00  [arcmin]
the incident angle in the POLAR coordinate at T0 is:
Theta: 87.0 [deg]
Phi: 98.4 [deg]

The analysis results presented above are preliminary. 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. 

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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