TITLE: GCN CIRCULAR NUMBER: 42685 SUBJECT: Konus-Wind detection of GRB 251108C DATE: 25/11/14 20:07:42 GMT FROM: Anna Ridnaia at Ioffe Institute <ridnaia@mail.ioffe.ru> A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin, A. Tsvetkova, M. Ulanov, and T. Cline, on behalf of the Konus-Wind team, report: The long-duration GRB 251108C (AstroSat-CZTI detection: Salunke et al., GCN 42664; IPN triangulation: Kozyrev et al., GCN 42680) triggered Konus-Wind at T0=83283.415 s UT (23:08:03.415). The burst light curve shows a multipeaked structure which starts at ~T0-0.2 s and has a total duration of ~8.5 s. The emission is seen up to ~6 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB251108_T83283/ As observed by Konus-Wind, the burst had a fluence of 1.51(-0.19,+0.23)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0-0.172 s, of 1.23(-0.23,+0.26)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+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -1.05(-0.10,+0.11) and Ep = 1415(-316,+464) keV (chi2 = 55/69 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.7 (chi2 = 53/68 dof). The spectrum near the maximum count rate (measured from T0 to T0+0.256 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model with alpha = -0.96(-0.17,+0.22) and Ep = 2202(-834,+1554) keV (chi2 = 26/30 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -1.4 (chi2 = 26/29 dof). All the quoted errors are at the 68% confidence level. All the quoted values are preliminary. View this GCN Circular online at https://gcn.nasa.gov/circulars/42685. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...