//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9446 SUBJECT: GRB 090528: Fermi GBM detection DATE: 09/05/30 15:34:09 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 04:09:01.14 UT on 28 May 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090528 (trigger 265176543 / 090528173). The on-ground calculated location, using the GBM trigger data, is RA = 134.9, DEC = -35.8 (J2000 degrees, equivalent to 09h 00m, -35d 48'), with an uncertainty of 3.4 degrees (radius, 1-sigma containment, statistical only; there is additionally a systematic error which is currently estimated to be 2 to 3 degrees). The GBM on-ground location is within two sigma of the Vela X-1 position, nevertheless we think this event is due to a real gamma-ray burst because intensity, duration and spectrum are unusual for Vela X-1 observed outburst. The angle from the Fermi LAT boresight is 81 degrees. The GBM light consists of one major structured pulse with a duration (T90) of about 68 s (8-1000 keV). The time-averaged spectrum from T0-5.120 s to T0+29.696 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -1.7 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 99 +/- 26 keV (chi squared 357 for 359 d.o.f.). The event fluence (8-1000 keV) in this time interval is (9.3 +/- 0.9)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+3.072 s in the 8-1000 keV band is 7.6 +/- 0.3 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: 9447 SUBJECT: GRB 090528B: Fermi GBM detection DATE: 09/05/30 15:35:59 GMT FROM: Andreas von Kienlin at MPE A. von Kienlin (MPE) reports on behalf of the Fermi GBM Team: "At 12:22:31.29 UT on 29 May 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090528B (trigger 265206153 / 090528516). The on-ground calculated location, using the GBM trigger data, is RA = 312.2, DEC = 32.7 (J2000 degrees, equivalent to 20h 49m, 32d 42'), with a statistical uncertainty of less than 1 degree (radius, 1-sigma containment) and an additional systematic error which is currently estimated to be 2 to 3 degrees. The angle from the Fermi LAT boresight is 65 degrees. This burst was also independently detected by INTEGRAL SPI-ACS. The GBM light curve shows a strong multiple peak event follwed by a weaker structered tail with a duration (T90) of about 102 s (8-1000 keV). The time-averaged spectrum from T0-2.048 s to T0+57.345 s is best fit by a Band function with Epeak = 172 +/- 12 keV, alpha = -1.10 +/- 0.04, and beta = -2.3 +/- 0.1 (chi squared 516 for 477 d.o.f.). The event fluence (8-1000 keV) in this time interval is (4.65 +/- 0.15)E-05 erg/cm^2. The 1-sec peak photon flux measured starting from T0+9.216 s in the 8-1000 keV band is 14.7 +/- 1.3 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: 9468 SUBJECT: GRB 090528B: MASTER-II Kourovka optical limit DATE: 09/06/01 08:30:40 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs V.Krushinski, I.Zalognikh, A.Popov, T.Kopytova Ural State University, Kourovka E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Belinski, N.Shatskiy, N.Tyurina, D.Kuvshinov, P.Balanutsa, V.V.Chazov, P.V.Kortunov, A.Kuznetsov Sternberg Astronomical Institute, Moscow State University K.Ivanov, S.Yazev Irkutsk State University A. Tlatov, A.V. Parhomenko, Kislovodsk Solar Station of the Pulkovo Observatory MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru, 2x500mm,2 x 4 square degrees, 2 x 16Mpx Apogee CCD) located at Kourovka Observatory has observed FERMI error box GRB_RA: 313.740d {+20h 54m 58s} (J2000) GRB_DEC: +32.350d {+32d 21' 00"} (J2000) 1.18 degres error box radius (Trigg Number 265206153) starting after sunset (19:18:23.275, ~7 hours after GRB time) with 180s exposure in R and V filters simultaniuosly at ~60 degrees zenit distance. Robot do not detect OT with limit: R>19.0 V>18.1 Our images cover 30% last 1 sigma error box (A. von Kienlin, GCN Circ 9447) The R-image is available at http://observ.pereplet.ru/images/GRB090528B/grb090528B.jpeg The black circle is A. von Kienlin, GCN Circ 9447 error box. The message may be cited. mailto: lipunov@sai.msu.ru //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9479 SUBJECT: GRB 090528B: Suzaku WAM observation of the prompt emission DATE: 09/06/02 11:09:48 GMT FROM: Yoshitaka Hanabata at Hiroshima U Y. Hanabata, T. Uehara, T. Takahashi, Y. Fukazawa (Hiroshima U.), K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi, K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara (Saitama U.), Y. Urata (NCU), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), Y. E. Nakagawa, T. Tamagawa (RIKEN), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team, report: The long GRB 090528B (Fermi-GBM trigger 265206153 / 090528516; von Kienlin et al., GCN9447) triggered the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 12:22:29.849 UT (=T0). The observed light curve shows a bright multi-peaked structure starting at T0-5 s, ending at T0+60 s, and very weak emission is seen up to T0+120 s. The total T90 duration is about 77 seconds. The fluence in 100 - 1000 keV was 3.08 (-0.16, +0.14) x10^-5 erg/cm2. The 1-s peak flux measured from T0+11s was 3.53 (-0.32, +0.27) photons/cm2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-5 s to T0+120 s is fitted by a single power-law with a photon index of 2.00 (-0.10, +0.11) (chi^2/d.o.f = 32.1/20). The light curves for this burst will be available at: http://www.astro.isas.jaxa.jp/suzaku/HXD-WAM/WAM-GRB/grb/trig/grb_table.html //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9483 SUBJECT: GRB 090528: Suzaku WAM observation of the prompt emission DATE: 09/06/03 01:55:34 GMT FROM: Yujin E. Nakagawa at RIKEN Y. E. Nakagawa, T. Tamagawa (RIKEN), K. Yamaoka, S. Sugita (Aoyama Gakuin U.), T. Uehara, Y. Hanabata, T. Takahashi, Y. Fukazawa (Hiroshima U.), M. Ohno, M. Suzuki, M. Kokubun, T. Takahashi (ISAS/JAXA), K. Kono, E. Sonoda, M. Yamauchi, N. Ohmori, H. Hayashi, K. Noda, A. Daikyuji, Y. Nishioka (Univ. of Miyazaki), W. Iwakiri, M. Tashiro, Y. Terada, A. Endo, K. Onda, T. Sugasahara (Saitama U.), Y. Urata (NCU), T. Enoto, K. Nakazawa, K. Makishima (Univ. of Tokyo), S. Hong (Nihon U.), N. Vasquez (Tokyo Tech.), on behalf of the Suzaku WAM team, report: The long GRB 090528 (Fermi/GBM trigger 265176543 / 090528173, von Kienlin et al., GCN 9446) was detected by the Suzaku Wide-band All-sky Monitor (WAM) which covers an energy range of 50 keV - 5 MeV at 04:09:01.00 UT (=T0). The observed light curve shows a single-peaked structure lasting from T0-8s, ending at T0+28s, with a duration (T90) of about 26.0 seconds. The fluence in 100 - 1000 keV was 1.9 (+0.2/-0.7) * 10^-6 erg/cm^2. The 1-s peak flux measured from T0+2.5s was 0.5 (+0.2/-0.3) photons/cm^2/s in the same energy range. Preliminary result shows that the time-averaged spectrum from T0-4s to T0+22s is well fitted by a single power-law with a photon index of 2.6 (+0.7/-0.5) (chi^2/d.o.f = 13/13). All the quoted errors are at statistical 90% confidence level, in which the systematic uncertainties are not included. The light curves for this burst are available at: http://www.astro.isas.ac.jp/suzaku/research/HXD-WAM/WAM-GRB/grb/untrig/grb_table.html