[vsnet-grb-info 19220] GRB 170315A: POLAR observation

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20906
SUBJECT: GRB 170315A: POLAR observation
DATE:    17/03/18 14:09:08 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 2017-03-15 13:57:53.0 UT(T0), during a routine on-ground search of data, POLAR detected GRB 170315A,
which was also observed by Fermi GBM (trigger # 511279081).

The POLAR light curve consists of multiple peaks with duration (T90) of 7.00 +/- 1.00 s measured from T0.
The 1.00 s peak flux at T0 + 4.50 s  is equal to 830 +/- 80 counts/sec.
POLAR recorded 3130 events from the burst.
Above measurements are in the energy range of about 15 - 300 keV.

LC_URL: http://polar.psi.ch/triggers/GRB_170315A_raw.png
     or http://polar.psi.ch/pub/lc.php?event=GRB+170315A

Using the best location from Fermi GBM, which is (J2000):
RA : 230.39 [deg]
Dec: 60.34 [deg]
Error: 9.18
the incident angle in the POLAR coordinate at T0 is:
Theta: 49.83 [deg]
Phi: 291.93 [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. 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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