TITLE: GCN CIRCULAR NUMBER: 5698 SUBJECT: GRB 061004: Optical afterglow candidate and redshift DATE: 06/10/05 21:08:41 GMT FROM: Pall Jakobsson at U Hertfordshire Pall Jakobsson (U. Hertfordshire), Johan P. U. Fynbo, Brian L. Jensen , Jens Hjorth (DARK, NBI), Andrew Levan (U. Hertfordshire), Nial Tanvir (U. Leicester), Paul Vreeswijk and Cedric Ledoux (ESO) report on behalf of a larger collaboration: Using FORS1 on the Very Large Telescope, we have imaged the GRB 061004 field (Ziaeepour et al. GCN 5691) on Oct 5.369 (0.542 days post-burst). Inside the revised XRT circle (Page et al. GCN 5695) we find an R ~ 23 mag point source, using photometric zeropoints from the ESO webpages. At present we cannot confirm that the source is fading. Its coordinates are: R.A.(J2000) = 06:31:10.71 Dec(J2000) = -45:54:28.7 with a 0.3" error in each coordinate. We obtained a 30 min spectrum (300V grating) of this source immediately after imaging. The spectrum displays an absorption feature around 5230 A, with the flux dropping substantially blueward of this feature. Associating it with Ly-alpha gives a redshift of z ~ 3.3 for this proposed afterglow candidate. A finding chart can be found at: http://www.dark-cosmology.dk/~brian_j/grb/grb061004.827/ We thank the Paranal staff, especially Chris Lidman and Rachel Gilmour for excellent support.