[vsnet-grb-info 3819] GRB060908: optical observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  5653
SUBJECT: GRB060908: optical observations
DATE:    06/09/29 14:58:49 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen at iki.rssi.ru>

M. Andreev, A. Sergeev (Terskol Branch of Institute of Astronomy), A.
Kurenya (Baksan Neutrino Observatory), A. Pozanenko (IKI) on behalf of
larger GRB follow up collaboration report:

We observed the afterglow of GRB060908  (Evans et al., GCN 5544) with 2m
telescope of Terskol Observatory on Sep. 08 (UT) 20:51:45 - 21:14:45. We
detect the afterglow on a combined image of 20x60 s exposure. Based on USNO
A2.0 field stars we estimate brightness of the optical transient:

Mid time (UT), Exposure, R_mag

Sep. 08.877    20x60 s   20.70 +/- 0.27

It should be noted that R magnitude of the star  (USNO-B1.0 0903-0022606  R
= 18.29) used in GCN 5552 (Wiersema et. al) is inconsistent with the
R-magnitude of the same star USNO A2.0 (0900-00494220   R = 14.9).
R-magnitudes of other field stars of the two catalogs USNO-B1.0 and USNO
A2.0 are also inconsistent by ~2.9 mag in average.

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