TITLE: GCN CIRCULAR NUMBER: 17794 SUBJECT: Konus-Wind observation of GRB 150430A DATE: 15/04/30 14:38:55 GMT FROM: Dmitry Svinkin at Ioffe Institute S. Golenetskii, R. Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 150430A (Swift/BAT detection: D'Elia et al., GCN Circ. 17789; MAXI/GSC detection: Fujita et al., GCN Circ. 17791; Fermi/GBM detection: Roberts and Younes, GCN Circ. 17793) triggered Konus-Wind at T0=1271.466 s UT (00:21:11.466). The burst light curve shows three well separated emission episodes: a weak episode at T-T0 ~ -320 s, the main episode at T-T0 ~ 0 s, and a weak episode at T-T0 ~ 100 s. The total burst duration is about 420 s. There is a hint of soft precursor at T-T0 ~ -440 s. The emission is seen up to ~5 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB150430_T01271/ As observed by Konus-Wind, the burst had a fluence of 2.95(-0.75,+1.14)x10^-5 erg/cm2, and a 256-ms peak flux, measured from T0+1.248 s, of 4.11(-1.02,+1.09)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the main episode (measured from T0 to T0+114.944 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.79(-0.69,+1.48), the high energy photon index beta = -2.21(-0.66,+0.33), the peak energy 157(-70,+93) keV (chi2 = 69/72 dof) The spectrum near the maximum count rate (measured from T0+0.000 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.47(-0.35,+0.45), the high energy photon index beta = -2.11(-0.24,+0.16), the peak energy 194(-38,+54) keV (chi2 = 80/97 dof) All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.