TITLE: GCN GRB OBSERVATION REPORT NUMBER: 1606 SUBJECT: GRB021004: BVRc photometry DATE: 02/10/08 19:42:01 GMT FROM: Alexei Pozanenko at IKI, Moscow E.A.Barsukova (SAO), V.P.Goranskij (Sternberg Institute), G.M.Beskin (SAO), V.L.Plokhotnichenko (SAO), A.S.Pozanenko (IKI). We have observed the GRB021004 afterglow (GCN 1564) with SAO RAN 1-m Zeiss telescope and UBVRcIc photometer with Electron K-585 CCD. Observations cover time interval from 7 to 12 hours after the burst. Exposure time of each frame is 10 minutes, the field is 3'x4'. Results of the photometry are in the table below. Standards are taken relative to A.Henden and U.Munari, AsApSuppl. v.143, 343 (1999) standard near V407 Cyg. R.A., Decl, 2000 Rc V B position from A1.0 C 0 26 57.9 +18 56 07 16.35 16.71 17.15 F 0 26 58.7 +18 56 56 15.53 16.30 17.13 +/-0.01 +/-0.02 +/-0.02 a 0 26 52.0 +18 55 13 13.85 14.55 15.29 +/-0.01 +/-0.02 +/-0.02 Date UT mag (Mean epoch) filter=Rc, Typical errors=0.05 021004 18 58 12 17.89 021004 19 31 49 17.88 021004 20 05 28 18.06 021004 20 41 33 18.09 021004 21 25 37 18.17 021004 21 58 50 18.35 021004 23 08 06 18.39 021004 23 41 19 18.54 021005 00 03 05 18.57 filter=V, Typical errors=0.07 021004 19 09 24 18.33 021004 19 42 55 18.34 021004 20 19 36 18.43 021004 20 52 43 18.45 021004 21 02 35 18.60 021004 21 36 45 18.66 021004 22 09 46 18.82 021004 23 27 40 18.89 021004 23 52 09 18.87 filter=B, Typical errors=0.10 021004 19 20 49 18.67 021004 19 54 03 18.78 021004 20 30 35 18.77 021004 21 14 29 18.98 021004 21 47 49 19.10 021004 22 20 46 19.05 021004 23 30 11 19.26 The data obtained is compatible with achromatic decay. Analysis of the data set is underway and result will be improved. The figures of BVRc observations may be found in http://grb.rssi.ru/GRB021004/ This message can be cited.