TITLE: GCN CIRCULAR NUMBER: 42297 SUBJECT: Konus-Wind detection of GRB 251007A DATE: 25/10/15 17:55:01 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 251007A (Swift-BAT detection: Ambrosi et al., GCN 42146; Laha et al., GCN 42186; Glowbug detection: Cheung et al., GCN 42151; CALET-GBM detection: Yoshida et al., GCN 42156; AstroSat CZTI detection: Salunke et al., GCN 42167; Insight-HXMT detection: Wang et al., GCN 42183; SVOM/GRM detection: Yu et al., GCN 42184) triggered Konus-Wind at T0=70671.956 s UT (19:37:51.956). The burst light curve shows a multipeaked structure which starts at ~T0-44.6 s and has a total duration of ~66.4 s. The emission is seen up to ~4 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB251007_T70671/ As observed by Konus-Wind, the burst had a fluence of 3.89(-0.15,+0.16)x10^-5 erg/cm2, and a 64-ms peak flux, measured from T0+0.656 s, of 7.08(-0.94,+0.95)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). The time-averaged spectrum of the burst (measured from T0 to T0+24.832 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 = -1.09(-0.06,+0.06) and Ep = 395(-27,+31) keV (chi2 = 108/98 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.6 (chi2 = 108/97 dof). The spectrum near the maximum count rate (measured from T0+0.256 to T0+8.448 s) is best fit in the 20 keV - 10 MeV range by a power law with exponential cutoff model with alpha = -1.20(-0.07,+0.07) and Ep = 436(-41,+50) keV (chi2 = 98/81 dof). Fitting by a GRB (Band) model yields the same alpha and Ep, and an upper limit on the high energy photon index: beta < -2.4 (chi2 = 96/80 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/42297. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...