TITLE: GCN CIRCULAR NUMBER: 9439 SUBJECT: GRB 090530A: ROTSE-III Detection of Optical Counterpart DATE: 09/05/30 03:30:24 GMT FROM: Heather Flewelling at IfA/Hawaii H. Flewelling (IfA), B. E. Schaefer (Louisiana State), Shashi Pandey (UMich) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 090530A (Swift trigger 353567). The first image was at 03:18:35.8 UT, 17.4 s after the burst (6.8 s after the GCN notice time). The unfiltered images are calibrated relative to USNO A2.0. We detect a new object, not visible in the DSS (second epoch), with coordinates: 11:57:40.5 +26:35:37.9 (J2000), with positional uncertainty of 1" or better start UT mag mlim(of image) ---------------------------------- 03:18:42.7 16.0 16.2 A jpeg image is available at http://www.rotse.net/images/gsb353567_3b00_img.jpg Note that the object marked 48 is the candidate in question. Continuing observations are in progress.