TITLE:   GCN CIRCULAR
NUMBER:  5824
SUBJECT: GRB 061121: ROTSE-III Confirmation of Optical Counterpart
DATE:    06/11/21 15:46:55 GMT
FROM:    Sarah Yost at U.Michigan  <sayost@umich.edu>

S.A. Yost (U Mich), B. E. Schaefer (Louisiana State), F. Yuan (U Mich), 
report on behalf of the ROTSE collaboration:

ROTSE-IIIa, located at Siding Spring Observatory, Australia, responded 
to GRB 061121 (Swift trigger 239899). The first image was at 15:22:49.6 
UT, 20.6 s after the burst (7.6 s after the GCN notice time). The 
unfiltered images are calibrated relative to USNO A2.0. We detect a 14.9 
magnitude, fading source with coordinates:

      09:48:54.4      -13:11:42.2    (J2000), with positional 
uncertainty of 1" or better.

This is coincident with the UVOT source (GCN 5823)


start UT    	mag     mlim(of image)
----------------------------------
15:23:46.2     14.9     14.9



A jpeg image is available at 
http://www.rotse.net/images/gsb239899_3a02_img.jpg Note that the object 
marked 65 is the candidate in question.

Continuing observations are in progress.