//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9689 SUBJECT: GRB 090718: Fermi GBM detection DATE: 09/07/20 14:45:43 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the Fermi GBM Team: "At 17:16:42.93 UT on 18 July 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090718 (trigger 269630204 / 090718720). The on-ground calculated location, using the GBM trigger data, is RA = 242.5, DEC = -6.6 (J2000 degrees, equivalent to 16h10m, -6d35'), with an uncertainty of 7.4 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 51 degrees. Since the source is weak, the time-averaged spectrum is poorly constrained." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9690 SUBJECT: GRB 090718B: Fermi GBM detection DATE: 09/07/20 14:49:19 GMT FROM: Alexander van der Horst at NASA/MSFC A.J. van der Horst (NASA/MSFC/ORAU) reports on behalf of the Fermi GBM Team: "At 18:17:42.84 UT on 18 July 2009, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 090718B (trigger 269633864 / 090718762). The on-ground calculated location, using the GBM trigger data, is RA = 274.1, DEC = -36.4 (J2000 degrees, equivalent to 18h16m, -36d23'), with an uncertainty of 1.2 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 76 degrees. The GBM light curve consists of several peaks with a duration (T90) of about 28 s (8-1000 keV). The time-averaged spectrum from T0 to T0+29.7 s is well fit by a power law function with an exponential high energy cutoff. The power law index is -1.21 +/- 0.02 and the cutoff energy, parameterized as Epeak, is 198 +/- 9 keV (chi squared 507 for 480 d.o.f.). The event fluence (8-1000 keV) in this time interval is (2.52 +/- 0.05)E-5 erg/cm^2. The 1-sec peak photon flux measured starting from T0+21.5 s in the 8-1000 keV band is 32.0 +/- 0.5 ph/s/cm^2. A Band function fits the spectrum equally well (chi squared 504 for 479 d.o.f.) with Epeak = 184 +/- 9 keV, alpha = -1.18 +/- 0.03 and beta = -2.59 +/- 0.26. The temporal and spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 9703 SUBJECT: Konus-RF and Konus-Wind observations of GRB 090718B DATE: 09/07/24 11:08:04 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, E. Mazets, V. Pal'shin, P. Oleynik, M. Ulanov, and D. Svinkin on behalf of the Konus-Wind and Konus-RF teams, and T. Cline on behalf of the Konus-Wind team, report: The long GRB 090718B (Fermi/GMM trigger 269633864/09071876; A.J. van der Horst, GCN 9690) triggered Konus-RF instrument onboard CORONAS-PHOTON s/c at T0=65863.878 s UT (18:17:43.878), and Konus-Wind at T0=65882.144 s UT (18:18:02.144), The burst light curve shows a smooth structure with a duration of ~35 s. The Konus-RF and Konus-Wind light curves of this GRB are available at http://www.ioffe.ru/LEA/GRBs/GRB090718_T65882/ As observed by Konus-RF the burst had a fluence of 2.6(-0.13, +0.13)x10-5 erg/cm2, and a 64-ms peak flux measured from T0+20.904 s of 5.0(-0.24, +0.24)x10-6 erg/cm2/s (both in the 20 keV - 1 MeV energy range). The time-integrated spectrum of the burst (from T0-2.0 to T0+34.0 s) is well fit (in the 20 keV - 1 MeV range) by GRB (Band) model for which: the low-energy photon index alpha = -1.3 ± 0.1, the high energy photon index beta = -4.6( < -2.2), the peak energy Ep = 250(-50, +35) keV (chi2 = 126/106 dof). The spectrum of the burst at the maximum count rate (from T0+20.5 to T0+21.0 s) is well fit (in the 20 keV - 1 MeV range) by GRB (Band) model for which: the low-energy photon index alpha = -0.83 ± 0.13, the high energy photon index beta = -3.0( < -2.3), the peak energy Ep = 245(-40, +45) keV (chi2 = 51/60 dof). Due to uncertainties in the burst incident angle the quoted values are preliminary. All the quoted errors are at the 90% confidence level. --