NUMBER:  2802
SUBJECT: GRB 041006 : Optical observations and Potential host galaxy
DATE:    04/10/14 10:17:18 GMT

J. P. U. Fynbo, B. L. Jensen, K. Pedersen, D. Watson, P. Jakobsson, G. Bjornsson, J. M. Castro Cerón, H. Pedersen, J. Hjorth (U. Copenhagen), D. Zucker (MPIA) and T. Pursimo (NOT) report:

"We have obtained two epochs of the field of GRB 041006 (Galassi et al., GCN #2770) at two epochs with the 2.56m Nordic Optical Telescope using the MOSCA instrument (R-band). At the position of the afterglow (Costa et al., GCN #2735), we detect the following:

Date (UT 2004) | t_b+  | exptime     | Seeing |  mag.
------------------------------------------------------------
Oct. 06.96       10.8h   300s+3x600s   ~0.8"    R~20.5
Oct. 11.18      112.2h   5x600s        ~1.9"    R~23.6

The photometry is relative to the magnitude of a nearby star as measured by Henden (GCN #2801). The source is clearly extended in the 2nd epoch image (although the seeing was poor), so the potential host galaxy is most likely contributing most of the flux.

A section of the 2nd epoch image can be seen at http://www.astro.ku.dk/~brian_j/grb/grb041006."

Section of the second epoch image (Oct. 11.2, 2004).
R:5x600s image taken with the NOT+MOSCA.
N up, E is left. The image section is 30x30 arcsec.
The position of the cross corresponds to the position of the OT in our first epoch image (at a position of (RA, Dec)(J2000.0) = (00:54:50.2, +01:14:04.7 -- in close agreement with the refined coordinates reported by Yamaoka et al. (GCN #2781).)