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[vsnet-grb-info 584] GRB021004, late time optical observations



TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  1717
SUBJECT: GRB021004, late time optical observations
DATE:    02/12/02 16:51:59 GMT
FROM:    Vladimir Sokolov at SAO RAS  <sokolov@sao.ru>

T.A. Fatkhullin, V.N. Komarova, A.V. Moiseev (SAO RAS) report for the
larger GOSH collaboration:


The field of the GRB 021004 optical transient was observed with the SCORPIO
instrument at the 6-m telescope of SAO RAS. The images were taken
starting from 15:30 to 17:45 UT on Nov 29 and from 18.55 to 20.00 UT on Nov 30
under conditions of thin cirrus with seeing of about 1.2 arcsec in the first
night and 1.5 arcsec in the second one. The V, Rc and Ic filters were used.
The absolute astrometry was done relatively to USNO-B1.0 stars with internal
error of 0.3 arcsec. We detect an object which coincides with the position
of the optical transient (Henden et al. GCN #1592)  within the astrometric
error. Photometric calibration was performed using 6 standards
(Henden et al. GCN #1630) in our FOV.
The results of the photometry are given below:

 Data    Filter  Exp.       OT mag.     Aperture
------------------------------------------
 29 Nov   Rc   15x180s   24.36+/-0.18   3.5 arcsec
 29 Nov    V    5x450s   24.53+/-0.18   3.5 arcsec
 30 Nov   Ic   14x120s   >23.9
------------------------------------------

At this stage it is not clearly whether the object is the pure host
galaxy. Further observations are planned.
Images can be seen at URL:
http://www.sao.ru/~sokolov/GRB/FOLLOWUP/GRB021004/GRB021004.html

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