TITLE: GCN CIRCULAR NUMBER: 13446 SUBJECT: Konus-Wind observation of GRB 120711A DATE: 12/07/11 18:35:12 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 long hard intense GRB 120711A (detected by the INTEGRAL/IBAS Gotz et al., GCN 13434; MAXI/GSC detection: Serino et al., GCN 13436; Fermi/GBM trigger 363667496/120711115: Gruber & Palassa, GCN 13437; Fermi/LAT detection: Tam, Li & Kong, GCN 13444) triggered Konus-Wind at T0=09955.810s UT (02:45:55.810) The light curve starts with a precursor at ~T0-65s followed by a strong hard double pulse lasting from ~T0-3 s to ~T0+50 s. Several short (100 - 200 ms) bright spikes are well detected over the general burst light curve in the ~T0+30 s to ~T0+40 s time interval. A a weak decaying emission tail in the soft energy channel G1(25-90 keV) is detectable till at least ~T0+400s. The emission during the main phase of the event is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB120711_T09955/ As observed by Konus-Wind the burst had a fluence of 3.8(-0.2,+0.2)x10-4 erg/cm2, and a 64-ms peak flux, measured from T0+32.576 s, of 3.6(-0.4,+0.4)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum of the burst (measured from T0 to T0+46.336 s) is best fit in the 20 keV - 10 MeV range with the GRB (Band) model, for which: the low-energy photon index alpha = -0.97 (-0.02, +0.02), the high energy photon index beta = -2.7 (-0.3, +0.2), the peak energy Ep = 1060(-60, +60) keV, chi2 = 95.7/87 dof. The spectrum at the maximum count rate (measured from T0+30.208 to T0+34.560 s) is best fit in the 20 keV - 10 MeV range with the GRB (Band) model, for which: the low-energy photon index alpha = -0.93 (-0.04, +0.04), the high energy photon index beta = -2.5 (-0.5, +0.3), the peak energy Ep = 1400(-160, +170) keV, chi2 = 85.5/87 dof. Assuming the likely GRB redshift of z=1.405 (Tanvir et al., GCN 13441) and a standard cosmology model with H_0 = 71 km/s/Mpc, Omega_M = 0.27, Omega_Lambda = 0.73: the isotropic energy release E_iso is (1.95 ± 0.1)x10^54 erg, the isotropic peak luminosity L_iso_max is (4.5 ± 0.5)x10^53 erg/s, and Ep_rest is (2550 ± 150) keV. All the quoted results are preliminary. All the quoted errors are at the 90% confidence level.