TITLE: GCN CIRCULAR NUMBER: 21167 SUBJECT: Konus-Wind observation of GRB 170529A DATE: 17/05/30 16:22:19 GMT FROM: Anna Kozlova at Ioffe Institute A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, 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 170529A (IPN triangulation: Hurley et al., GCN 21165) triggered Konus-Wind at T0=25541.567 s UT (07:05:41.567). The burst light curve shows two separate multipeaked episodes: the first from ~T0-6 s to ~T0+52 s and the second weaker/softer from ~T0+176 s to ~T0+220 s. The total duration of the burst is ~226 s. The emission is seen up to 20 MeV. As observed by Konus-Wind, the burst had a fluence of 1.73(-0.40,+0.62)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+7.504 s, of 1.54(-0.27,+0.28)x10^-5 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+222.464 s) is best fit in the 20 keV - 20 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.96(-0.16,+0.46), the high energy photon index beta = -2.23(-1.36,+0.41), the peak energy Ep = 422(-188,+142) keV (chi2 = 89/98 dof). The spectrum near the maximum count rate (measured from T0+6.656 to T0+11.008 s) is best fit in the 20 keV - 20 MeV range by the GRB (Band) model with the following parameters: the low-energy photon index alpha = -0.49(-0.10,+0.11), the high energy photon index beta = -2.41(-0.28,+0.18), the peak energy Ep = 486(-54,+59) keV (chi2 = 75/87 dof). The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB170529_T25541/ All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.