TITLE:   GCN CIRCULAR
NUMBER:  7667
SUBJECT: GRB 080503: New candidate afterglow/host in Gemini imaging
DATE:    08/05/03 15:30:13 GMT
FROM:    Daniel Perley at U.C. Berkeley  <dperley@astro.berkeley.edu>

J. S. Bloom and D. A. Perley (UC Berkeley) report on behalf of a larger 
collaboration:

We obtained a sequence of images of the field of GRB 080503 (Mao et al. 
GCN 7665) from Gemini North using GMOS. In a stack of five 180s 
exposures starting 2008-05-03 13:23:39 UT, we detect a faint source 
("s1") consistent with the Mao et al. XRT position at:

  19:06:28.694 +68:47:37.71 J2000

With a positional uncertainty of about 250 mas. Given the faintness of 
the source, we can claim neither variability nor that the source is 
pointlike, but it is possible that the source is the host and/or the 
afterglow. Note that s1 is not the source we originally identified as 
the possible afterglow in Perley et al. (GCN 7666); we now believe that 
that object identified in the Keck guider image was outside the XRT 
error circle and unrelated to the GRB.

This and other sources of interest near the XRT position are encircled 
in green in the finder:

       http://lyra.berkeley.edu/~jbloom/grb080503.png

We thank Rachel Mason of Gemini for her assistance.