LEFT: i:3x300s smoothed image (ca. 1x1 arcmin, N up, E left) taken with NOT+ALFOSC at May 07.13, 2006 UT at an airmass of 4.
   RIGHT: i:5x500s smoothed image taken with NOT+ALFOSC at May 09.00, 2006 UT.

The circle marks the revised 90% confidence XRT error-circle, the position of the OT is marked by lines.
The insert shows an un-smoothed close-up of the OT position.
(The elongation of the PSF of the sources is due to atmospheric diffraction caused by the high airmass. The wavy lines are caused by fringing.)
 

NUMBER:  5094
SUBJECT: GRB060507: optical afterglow detection
DATE:    06/05/09 

Christina C. Thoene, Brian L. Jensen, Johan Fynbo (Dark Cosmology Centre), Jan-Erik Solheim (University of Oslo) report

We observed the field of GRB060507 (GCN 5084) in the I-band with the NOT and ALFOSC on La Palma, starting at May 7th, UT 03:08:19 (1.13h after the burst) at high airmass. On the edge of the XRT revised error circle (90% confidence) (GCN 5087) we detect a new source at the position (J2000)

RA = 05:59:50.52 Dec = +75:14:55.9

The preliminary I-band magnitude obtained from 3x300s stacked images with a mean time of 1.3h after the burst is

I = 19.1 +- 0.1
(compared to four nearby USNO stars)

5x300 I-band images from May 9th show that the source is transient and therefore likely to be the afterglow of GRB060507

A finding chart is available at: http://www.astro.ku.dk/~brian_j/grb/grb060507.079/ "