//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10226 SUBJECT: GRB 091123: Fermi GBM detection of a very long burst DATE: 09/12/01 18:16:00 GMT FROM: Sheila McBreen at MPE S. McBreen (UCD/MPE), V. Connaughton (UAH), C. Wilson-Hodge (NASA MSFC), M. Finger (USRA) and D. Tierney (UCD) report on behalf of the Fermi GBM Team: "At 07:08:37.26 UT on 23 November 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 091123 (trigger 280652919 / 091123298). The on-ground calculated location, using the GBM trigger data, is RA = 297.1, DEC = -29.2 (J2000 degrees, equivalent to 19 h 48 m, -29 d 12'), with an uncertainty of 2.4 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 106 degrees. This burst was also independently detected by INTEGRAL SPI-ACS and Konus-Wind. The GBM light curve consists of 4 main emission phases, each containing structure, separated by long periods of quiescence. Comparison with Konus-Wind data shows that the the event was already on-going when when it rose above the Earth's horizon. This allows a further constraint to be placed on the possible arrival direction of this burst. A plot showing the 3-sigma localization contours (statistical only) and the limb of the Earth at T0, T0-5, and T0+5 s is available at: http://gammaray.nsstc.nasa.gov/gbm/science/loc_091123298.gif In the GBM data alone, the burst has a duration of at least 650 sec (8-1000 keV). The time-averaged spectrum from T0-5 s to T0+650 s is adequately fit by a power law function with an exponential high energy cutoff. The power law index is -1.08 +/- 0.05 and the cutoff energy, parameterized as Epeak, is 101.30 (+5.16/-4.52) keV (C-stat 1008 for 355 d.o.f.). There is significant spectral evolution within the fitted time interval. The event fluence (8-1000 keV) in this time interval is (4.07 +/- 0.09)E-05erg/cm^2. The 1-sec peak photon flux measured starting from T0+11.2 s in the 8-1000 keV band is 6.1 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." We thank Valentin Pal'shin for providing the Konus-Wind lightcurves and informing us of the burst occultation by the Earth before the GBM trigger time. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10228 SUBJECT: Konus-Wind observation of very long GRB 091123 DATE: 09/12/02 15:22:37 GMT FROM: Valentin Pal'shin at Ioffe Inst S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team report: A very long GRB 091123 was detected by Konus-Wind in the waiting mode at ~T0=25585 s UT (07:06:25). The most part of the burst was also detected and localized by Fermi-GBM, while it missed the first ~130 s due to the Earth occultation (McBreen et al., GCN 10226). The burst light curve shows several pulses with a total duration of ~800 s. As observed by Konus-Wind, the burst had a fluence of (8.3 +/- 0.8)x10^-5 erg/cm2 (in the 20 - 1300 keV energy range). Modeling the K-W 3-channel time-integrated spectrum (from T0 to T0+806 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.49 +/- 0.36, Ep = 243 +/- 80 keV. The 3-channel spectrum of the most intense pulse (from T0+100 s to T0+150 s) can be modeled by a power law with exponential cutoff model with alpha = -1.03 +/- 0.11, Ep = 293 +/- 35 keV. The fluence of this pulse is (3.17 +/- 0.16)x10^-5 erg/cm2. All the quoted errors are estimated at the 1 sigma confidence level. The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB091123/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 10250 SUBJECT: GRB 091123: Suzaku WAM observation of the prompt emission DATE: 09/12/07 01:56:40 GMT FROM: Norisuke Ohmori at Miyazaki U N. Ohmori, E. Sonoda, K. Kono, H. Hayashi, A. Daikyuji, Y.Nishioka, K. Noda, M. Yamauchi (Univ. of Miyazaki), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), K. Yamaoka (Aoyama Gakuin U.), S. Sugita (Nagoya U.), T. Sugasahara, M. Tashiro, Y. Terada, A. Endo, K. Onda, W. Iwakiri (Saitama U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), N. Vasquez (Tokyo Tech.), Y. Urata, H.M Lin (NCU), Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.), on behalf of the Suzaku WAM team, report The very long GRB 091123 (Fermi-GBM trigger #280652919 / 091123298; McBreen et al., GCN 10226) was detected by the the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 07:07:42 UT (=T0). The observed light curve shows several pulses with a total duration of at least 650 s. The first bright emission episode was seen starting at T0-90 s, ending at T0+90 s. After the emission returned to the background level, three pulses was observed again at T0+220 s, T0+450 s, and T0+600 s, respectively. The fluence in 100 - 1000 keV was 3.78 (-0.59, +0.45) x10^-5 erg/cm^2. The 1-s peak flux measured from T0+45s was 2.08 (-0.31, +0.27) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-90s to T0+607s is fitted by a single power-law with a photon index of 2.30 (-0.14, +0.16) (chi^2/d.o.f. = 63.4/99). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves with 1-sec time resolution for this burst will be appeared at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html