TITLE: GCN CIRCULAR NUMBER: 1582 SUBJECT: GRB 021004: Optical observations DATE: 02/10/05 16:38:36 GMT FROM: T.P. Prabhu at Indian Astro. Obs. G.C. Anupama, D.K. Sahu, B.C. Bhatt and T.P. Prabhu, (Indian Institute of Astrophysics, Bangalore) report on behalf of a larger collaboration optical observations of GRB 021004 obtained from the 2-m Himalayan Chandra Telescope, Indian Astronomical Observatory, Hanle: We have monitored GRB 021004 in BVRI bands and obtained spectra with a resolution of 1.8 nm on 2002 October 4. The spectrum in the range of 500-1000 nm at October 4.883 UT shows z=1.38 and 1.60 reported in GCN #1569 and also indicates a higher redshift of z=1.72. The absorption-lines identified are: Obs (A) ident (A) z 5576 FeII 2343 1.38 6093 FeII 2343 1.60 6166 FeII 2586 1.38 6654 MgII 2796 1.38 6669 MgII 2803 1.38 6757 FeII 2599 1.60 7269 MgII 2796 1.60 7296 MgII 2803 1.60 7601 MgII 2796 1.72 7629 MgII 2803 1.72 Assuming the USNO star has R=15.64, the R magnitudes at the beginning and end of observing run were: 2002 October 4.70 UT R=17.44 4.95 UT R=18.59 [GCN OPS NOTE (05oct02): This submission was received at 13:52 05 Oct 02 UT, but was delayed in distribution due to the lack of an entry in the vetting list. A new entry was added and the submission manually invoked.]