TITLE:   GCN CIRCULAR
NUMBER:  7891
SUBJECT: GRB080607: optical observation
DATE:    08/06/21 12:16:51 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

V. Rumyantsev (CrAO),  A. Pozanenko (IKI) report on behalf of larger GRB 
follow-up collaboration:

We observed the field of  Swift GRB 080607 (Mangano  et al., GCN 7847)  on 
June 07 between (UT) 19:54 - 21:05  with Zeiss-1000 (Simeiz) telescope of 
CrAO observatory. We detect faint optical  source in coordinates

RA(J2000):  12 59 47.24
Dec(J2000): +15 55 08.74

with uncertainties of 0.5".

The source looks extended. The source is within enhanced XRT position 
(Osborne et al., GCN 7853), however the source position is apart ~2" from 
coordinates reported for the afterglow (Rujopakarn et al., GCN 7846, Mangano 
et al., GCN 7847, Chornock et al., GCN 7856).
 It is not clear is the source of  a putative host galaxy + afterglow or the 
source is not  related.
A photometry is obtained in comparison with nearby USNOB-1.0 star 12 59 
45.62   +15 54 19.10  assuming R=17.91:

T0+       Exposure  R_mag  UL
(mid)

0.5985 d   35x120  s    22.00 +/- 0.25  22.5

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