TITLE: GCN CIRCULAR NUMBER: 14872 SUBJECT: Konus-Wind observation of GRB 130610B DATE: 13/06/11 16:23:38 GMT FROM: Dmitry Frederiks at Ioffe Institute S. Golenetskii, R.Aptekar, D. Frederiks, V. Pal'shin, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 130610B (IPN triangulation: Hurley at al., GCN 14868) triggered Konus-Wind at T0=76879.093 s UT (21:21:19.093). The light curve from ~T0-0.5 s to ~T0+16s shows multiple pulses with decaying spectral hardness. The pulses form a quasi-periodic structure with the period of ~1s during first ~5 seconds of the burst, which is followed, after T0+7s, by the three pulses separated by ~2.7s. A weak count rate excess in the soft energy channel (20-80 keV) is observed from ~T0-170 s to ~T0-100 s in the instrument background mode; however, its attribution to GRB 130610B is not yet confirmed. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB130610_T76879/ As observed by Konus-Wind, the burst had a fluence of (8.5 ± 0.4)x10-6 erg/cm2, and a 64-ms peak flux, measured from T0+0.256s, of (6.0 ± 0.5)x10-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-integrated spectrum (measured from T0 to T0+16.640 s) is best fit in the 20 keV - 15 MeV range by the cutoff power law with the following model parameters: the photon index alpha = -1.7 ± 0.1, the peak energy Ep = 62 ± 9 keV, chi2 = 99/98 dof. The 3-channel spectrum at the maximum count rate (measured from T0+0.256 to T0+0.384 s) can be modeled, in the 20 keV - 1.35 MeV range, by the cutoff power law with the following model parameters: the photon index alpha = -0.52 ± 0.08, and the peak energy Ep = 444 ± 30 keV. All the quoted results are preliminary.