TITLE: GCN CIRCULAR NUMBER: 18203 SUBJECT: Konus-Wind observation of GRB 150824A DATE: 15/08/25 16:37:18 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko, A. Kozlova, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, bright GRB 150824A (Fermi-GBM detection: Bissaldi & Burns, GCN 18201; IPN triangulation: Hurley et al., GCN 18202) triggered Konus-Wind at T0=6810.119 s UT (01:53:30.119). The light curve shows several pulses in the interval from ~T0-0.5 s to ~T0+15 s. The emission is seen up to ~5 MeV. As observed by Konus-Wind, the burst had a fluence of 1.8(-0.2,+0.2)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.896 s, of 7.6(-0.8,+0.9)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+16.384 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.96 (-0.16,+0.11), the high energy photon index beta = -3.11 (-6.89,+0.44), the peak energy Ep = 197 (-16,+22) keV, chi2 = 106/97 dof. The spectrum near the peak count rate (measured from T0 to T0+8.192 s) is best fit in the 20 keV - 15 MeV range by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.83 (-0.11,+0.12), the high energy photon index beta = -2.79 (-0.56,+0.29), the peak energy Ep = 200 (-19,+20) keV, chi2 = 90/92 dof. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150824_T06810/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.