TITLE: GCN CIRCULAR NUMBER: 11798 SUBJECT: GRB 110318A: Swift detection of a burst DATE: 11/03/18 13:21:49 GMT FROM: Scott Barthelmy at NASA/GSFC B. Sbarufatti (INAF-OAB/IASFPA), S. D. Barthelmy (GSFC), M. M. Chester (PSU), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), P. A. Evans (U Leicester), N. Gehrels (NASA/GSFC), J. M. Gelbord (PSU), C. Gronwall (PSU), C. Guidorzi (U Ferrara), S. T. Holland (CRESST/USRA/GSFC), J. A. Kennea (PSU), R. Margutti (INAF-OAB), A. Melandri (INAF-OAB), K. L. Page (U Leicester), P. Romano (INAF-IASFPA), C. J. Saxton (UCL-MSSL), M. H. Siegel (PSU), E. Sonbas (GSFC/USRA/Adiyaman Univ.) and C. A. Swenson (PSU) report on behalf of the Swift Team: At 13:14:19 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 110318A (trigger=449542). Swift did not slew to the burst because of the Sun observing constraint. The BAT on-board calculated location is RA, Dec 338.274, -15.282, which is RA(J2000) = 22h 33m 06s Dec(J2000) = -15d 16' 55" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows two main peaks with a duration of about 20 sec. The peak count rate was ~7000 counts/sec (15-350 keV), at ~2 sec after the trigger. Due to a Sun observing constraint, Swift cannot slew to the BAT position until 05:00 UT on 2011 April 11. There will thus be no XRT or UVOT data for this trigger before this time. Burst Advocate for this burst is B. Sbarufatti (boris.sbarufatti AT brera.inaf.it). 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.)