TITLE: GCN CIRCULAR NUMBER: 14691 SUBJECT: GRB 130521A: Swift detection of a burst DATE: 13/05/21 22:58:17 GMT FROM: David Palmer at LANL C. Pagani (U Leicester), N. Gehrels (NASA/GSFC), H. A. Krimm (CRESST/GSFC/USRA), C. J. Mountford (U Leicester), K. L. Page (U Leicester), D. M. Palmer (LANL), T. Sakamoto (AGU) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 22:49:16 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 130521A (trigger=556344). Swift could not slew to the burst due to the Sun constraint. The BAT on-board calculated location is RA, Dec 87.559, +14.452 which is RA(J2000) = 05h 50m 14s Dec(J2000) = +14d 27' 09" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single peak structure with a duration of about 6 sec. The peak count rate was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 05:50 UT on 2013 August 06. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is C. Pagani (cp232 AT star.le.ac.uk). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.)