//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12044 SUBJECT: LAT Observations of GRB110529A DATE: 11/05/29 21:31:17 GMT FROM: Julie McEnery at NASA/GSFC Julie McEnery (NASA/GSFC), Johan Bregeon (INFN Pisa) and Dan Kocevski (SLAC) report on behalf of the Fermi-LAT collaboration. The Fermi Large Area Telescope (LAT) detected emission from GRB 110529A also detected by GBM (trigger 328322924) at 00:48:42.87 UT on May 29, 2011. The GBM location was inside the LAT field of view at an angle of ~30 degrees to the LAT boresight; no significant excess is seen using standard analysis procedures. Using a non-standard data selection, over 30 counts above background were detected within a 0.1 s interval coinciding with the time of the GBM emission. This data selection has insufficient spatial resolution to provide a reliable LAT localization. Since an excess of events were not seen using the standard analysis selection, this detection is likely due to low energy gamma-rays (below 100 MeV). Further analysis is ongoing. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12045 SUBJECT: Konus-Wind observation of GRB 110529A DATE: 11/05/30 13:48:54 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report: The short hard GRB 110529A (GBM trigger 328322924, GCN 12044) triggered Konus-Wind at T0=2920.249s UT (00:48:40.249) The burst light curve consists of a single sharp pulse with a total duration of ~0.57 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB110529_T02920/ As observed by Konus-Wind the burst had a fluence of (5.1 ± 1.1)x10-6 erg/cm2, and a 16-ms peak flux, measured from T0, of 7.0(-3.0,+2.2)x10-5 erg/cm2/s (both in the 20 keV - 5 MeV energy range). The time-integrated spectrum of the burst (from T0 to T0+0.256 s) is best fitted in the 20 keV - 5 MeV range by the GRB (Band) model, for which: the low-energy photon index alpha = -0.43 (-0.36, +0.89), the high energy photon index beta = -1.7 (-0.3, +0.2), the peak energy Ep = 428(-226, +363) keV, chi2 = 14.3/26 dof. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12047 SUBJECT: GRB 110529A: Fermi GBM detection DATE: 11/05/30 16:42:47 GMT FROM: Michael Burgess at UAH J. Michael Burgess (UAH) and Sylvain Guiriec (UAH) report on behalf of the Fermi GBM Team: "At 00:48:42.87 UT on 29 May 2011, the Fermi Gamma-Ray Burst Monitor triggered and located the very bright and short GRB 110529A (trigger 110529034 / 110529034). The on-ground calculated location, using the GBM trigger data, is RA = 118.33, DEC = 67.91 (J2000 degrees, equivalent to 7h 53m, +67d 54'), with an uncertainty of 1.5 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The angle from the Fermi LAT boresight is 30 degrees. This GRB was also observed by Konus-Wind (GCN 12045). The GBM light curve consists of two short bright peaks with a duration (T90) of about 0.41s (50-300 keV). The time-averaged spectrum from T0-0.0 s to T0+.44s is adequately fit by a Band function with Epeak = 1161 +/- 265 keV, alpha = -0.88 +/- 0.06, and beta = -2.05+/- 0.15 The event fluence (10-1000 keV) in this time interval is (2.32 +/- 0.01)E-6 erg/cm^2. The 0.256-sec peak photon flux measured starting from T0+0.00 s in the 10-1000 keV band is 23.6826 +/- 0.68 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 12061 SUBJECT: GRB 110529A: Suzaku WAM observation of the prompt emission DATE: 11/06/03 06:33:41 GMT FROM: Satoshi Sugita at Aoyama Gakuin U. S. Sugita (Nagoya U.), Y. E. Nakagawa (Waseda U.), W. Iwakiri, Y. Terada, M. Tashiro, K. Takahara, T. Yasuda (Saitama U.), T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.), K. Yamaoka (Aoyama Gakuin U.), M. Ohno, M. Kokubun, T. Takahashi (ISAS/JAXA), N. Ohmori, M. Akiyama, M. Yamauchi (Univ. of Miyazaki), Y. Urata, P. Tsai, C-J. Chuang (NCU), K. Nakazawa, K. Makishima (Univ. of Tokyo), on behalf of the Suzaku WAM team, report: The bright short GRB 110529A (McEnery et al., GCN 112044) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 2011-05-29 00:48:42.855 UT (=T0). The observed light curve shows a single FRED-like peak starting at T0s, ending at T0+0.438s, with a duration (T90) of 0.344 +/- 0.049 seconds. The fluence in 100 - 1000 keV was 1.93 (+/- 0.12) x 10^-6 erg/cm^2. The 1-s peak flux measured from T0s was 7.16 (+/- 0.45) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0s to T0+0.5s is well fitted by a power-law with exponential cutoff model: dN/dE ~ E^{-alpha} * exp(-(2-alpha)*E/Epeak) with alpha 1.02 (-0.20, 0.16)), and Epeak 1052 (-196, +254) keV (chi^2/d.o.f. = 55.9/52). We also shows the results with the same spectrum fitted by a GRB Band model fixing beta of -2.5 the low-energy photon index alpha: -0.80 (-0.26, 0.34), the high-energy photon index beta: -2.5 (fixed), and the peak energy Epeak: 791 (-161, 242) keV (chi^2/d.o.f = 53.6/52). All the quoted errors are at statistical 90% confidence level. The light curves for this burst are available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html