[vsnet-grb-info 2999] GRB200618: optical polarimetry and photometry

[GCN Circulars]

TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  4836
SUBJECT: GRB200618: optical polarimetry and photometry
DATE:    06/02/26 15:25:13 GMT
FROM:    Valeri Larionov at NIAI SpBU  <vlar at crao.crimea.ua>

V. Larionov and L.Larionova from St.Petersburg University (Russia)
<vml at VL1104.spb.edu>, <vlar at nm.ru> report:

We imaged GRB20060218 with 70-cm telescope of Crimean Astrophysical
observatory (Ukraine) and ST-7 camera of St.Petersburg University
in photometric and polarimetric mode. Observations were made in R band from 
February 20.17 to February 23.18. The rate of brightening in this period was 
0.18 mag/day. The polarization reached maximum of 6% on February 21
and decreased to 3% on February 23. The positional angle remained 
practically unchanged, 110+\-5 deg. The high and variable polarization
gives evidence of strongly aspherical or non-thermal component in
GRB20060218/SN2006aj radiation.

This message is citeable.