[vsnet-grb-info 7173] GRB 081230: ROTSE-III Detection of Optical Counterpart

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8754
SUBJECT: GRB 081230: ROTSE-III Detection of Optical Counterpart 
DATE:    08/12/30 21:20:41 GMT
FROM:    Fang Yuan at ROTSE  <yuanfang at umich.edu>

F. Yuan (U Mich), E.S. Rykoff (UCSB), report on behalf of the ROTSE  
collaboration:

ROTSE-IIIc, located at the H.E.S.S. site at Mt. Gamsberg, Namibia,  
responded to GRB 081230 (Swift trigger 338633). The first image was at  
20:47:53.4 UT, 700.8 s after the burst (8.4 s after the GCN notice  
time). The unfiltered images are calibrated relative to USNO A2.0. We  
detect a 19.1 magnitude, steady source in the XRT error box with  
coordinates:

      02:29:19.35      -25:08:49.22    (J2000), with positional  
uncertainty of 1" or better

start UT    	mag     mlim(of image)
----------------------------------
20:49:23.0     19.1     19.2


This source is not visible in DSS (second epoch), 2MASS or the  
MPChecker database.

A jpeg image is available at http://www.rotse.net/images/gsb338633_3c021-030_key.jpg

Continuing observations are in progress.