[AAVSO-HEN] GRB 070406: Star in XRT error circle S2 is an AGN?

[grb at aavso.org]

The following is a GCN Circular circulated via the AAVSO network.
For an archive and more information on circulars visit:
http://lheawww.gsfc.nasa.gov/docs/gamcosray/legr/bacodine/gcn3_archive.html

TITLE:   GCN CIRCULAR
NUMBER:  6266
SUBJECT: GRB 070406: "Star" in XRT error circle S2 is an AGN?
DATE:    07/04/10 21:45:34 GMT
FROM:    Edo Berger at Carnegie Obs  <eberger at ociw.edu>

E. Berger (Carnegie Observatories) reports:

"Inspection of our Gemini-North/GMOS images taken on 2007 April 8.39 UT in 
0.55" seeing reveal that the source near the center of XRT source S2 (GCN 
6265), which is classified as a star in SDSS, is embedded within a clearly 
extended source.  This may be a chance superposition of a star on top of a 
background galaxy, or more likely, it is a bright AGN, similar to the 
source coincident with XRT source S1 (GCN 6262).  Additional XRT 
observations are required to verify whether the source is steady.

We also note that in addition to the galaxy located 3.7" from the XRT 
position, our images reveal five fainter extended sources within the error 
circle."