TITLE: GCN CIRCULAR NUMBER: 16120 SUBJECT: GRB 140419A: ROTSE-III Detection of Optical Counterpart DATE: 14/04/19 04:40:43 GMT FROM: Tolga Guver at UA GRB 140419A: ROTSE-III Detection of Optical Counterpart T. Guver (Istanbul Univ.), F. V. Ferrante (SMU), H. Flewelling (IfA/Hawaii), R. Kehoe (SMU), G. Dhungana (SMU) report on behalf of the ROTSE collaboration: ROTSE-IIIb, located at McDonald Observatory, Texas, responded to GRB 140419A (Swift trigger 596426, GCN 16118). The first image was at 04:07:18.7 UT, 27.3 s after the burst (8.7 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: 08:27:57.7 +46:14:25.9 (J2000), with positional uncertainty of 1' or better start UT mag mlim(of image) ---------------------------------- 04:07:18.7 13.5 15.0 The object first detected with a magnitude of ~13.5, brightened to 12.5 magnitudes in ~70 seconds then the brightness decayed fast to ~14.3 magnitudes at about 350 seconds. A jpeg image is available at http://www.rotse.net/images/gsq596426_3b01_img.jpg Note that the object marked 8 is the candidate in question. Continuing observations are in progress. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.