//////////////////////////////////////////////////////////////////////// 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.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11802 SUBJECT: GRB 110318A: Swift-BAT refined analysis DATE: 11/03/18 18:14:45 GMT FROM: Scott Barthelmy at NASA/GSFC S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (GSFC/UMBC), B. Sbarufatti (INAF-OAB/IASFPA), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (MSU) (i.e. the Swift-BAT team): Using the data set from T-114 to T+595 sec from the recent telemetry downlink, we report further analysis of BAT GRB 110318A (trigger #449542) (Sbarufatti, et al., GCN Circ. 11798). The BAT ground-calculated position is RA, Dec = 338.292, -15.278 deg, which is RA(J2000) = 22h 33m 10.0s Dec(J2000) = -15d 16' 40.9" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 27%. The mask-weighted light curve shows a small precursor peak between T-8 and T-2 sec. The main peak starts at ~T-1 sec, peaks at ~T+1 sec, and ends at ~T+15 sec. T90 (15-350 keV) is 16.0 +- 1.7 sec (estimated error including systematics). The time-averaged spectrum from T-13.0 to T+10.6 sec is best fit by a power law with an exponential cutoff. This fit gives a photon index 1.05 +- 0.23, and Epeak of 94.3 +- 23.7 keV (chi squared 43.1 for 56 d.o.f.). For this model the total fluence in the 15-150 keV band is 4.9 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured from T+1.95 sec in the 15-150 keV band is 8.0 +- 0.5 ph/cm2/sec. A fit to a simple power law gives a photon index of 1.58 +- 0.05 (chi squared 59.4 for 57 d.o.f.). All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/449542/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 11805 SUBJECT: GRB 110318A: Fermi GBM detection DATE: 11/03/18 22:15:54 GMT FROM: Gerard Fitzpatrick at UCD G. Fitzpatrick (UCD) reports on behalf of the Fermi GBM Team:  "At 13:14:16.70 UT on 18th March 2011, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 110318 (trigger 322146858 / 110318552),  which was also detected by the Swift/BAT (Sbarufatti et al. 2011,  GCN 11798). The GBM on-ground location is consistent with the Swift  position. The angle from the Fermi LAT boresight is 70 degrees. The GBM light curve consists of single peak with a duration (T90) of about 12 s (50-300 keV).  The time-averaged spectrum from T0-1 s to T0+10 s is   fit well with  a power law function with an exponential high-energy cutoff.  The power law index is -0.86 +/- 0.04 and the cutoff energy, parameterized as Epeak, is 114.70 +/- 3.72 keV A Band function fits the spectrum equally well with Epeak= 107.00 +/- 5.18 keV, alpha =-0.80 +/- 0.05, and beta = -2.74 +/- 0.25. The event fluence (10-1000 keV) in this time interval is  (8.05 +/- 0.15)E-6 erg/cm^2. The 1-sec peak photon flux measured  starting from T0-1 s in the 8-1000 keV band  is 10.97 +/- 0.29 ph/s/cm^2. The spectral analysis results presented above are preliminary;  final results will be published in the GBM GRB Catalog." [GCN OPS NOTE(19mar11): Per author's request, the citation for GCN Circ 11798 was corrected.]