TITLE: GCN CIRCULAR NUMBER: 16117 SUBJECT: Konus-Wind observation of GRB 140416A DATE: 14/04/18 14:46:57 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, and T. Cline on behalf of the Konus-Wind team, report: The long-duration, very intense GRB 140416A (Fermi GBM detection: Jenke, GCN 16115; IPN triangulation: Hurley at al., GCN 16116) triggered Konus-Wind at T0=5196.209 s UT (01:26:36.209). The burst light curve shows multiple peaks from ~T0-24 s to ~T0+28 s. The emission is seen up to ~8 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB140416_T05196/ As observed by Konus-Wind, the burst had a fluence of 6.9(-0.1,+0.1)x10-5 erg/cm2, and a 64-ms peak flux, measured from T0+7.168 s, of 1.5(-0.1,+0.1)x10-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum (measured from T0 to T0+32.768 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 = -1.43 (-0.06,+0.07), the high energy photon index beta = -2.95 (-0.31,+0.18), the peak energy Ep = 97 (-4,+4) keV, chi2 = 88.4/96 dof. The spectrum near the maximum count rate (measured from T0+6.912 to T0+7.424 s) by the GRB (Band) function with the following model parameters: the low-energy photon index alpha = -0.78 (-0.14,+0.15), the high energy photon index beta = -3.8 (-6.2,+0.6), the peak energy Ep = 176 (-16,+18) keV, chi2 = 81.5/90 dof. All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.