TITLE: GCN CIRCULAR NUMBER: 44722 SUBJECT: Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a DATE: 26/05/28 12:11:41 GMT FROM: Dmitry Svinkin at Ioffe Institute <dmitrysvinkin@gmail.com> D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The short-duration GRB 260527A triggered Konus-Wind at T0=22572.142 s UT (06:16:12.142). The burst light curve shows a multi-peaked structure which starts at ~T0-0.1 s and has a total duration of ~0.2 s. The emission is seen up to ~10 MeV. The burst occurred ~4 min before the Einstein Probe detection of EP260527a (Yang et al., GCN 44718), and also the KW ecliptic latitude response is consistent with the EP260527a position. This suggests a common origin of two events, which will be further investigated. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB260527_T22572/ As observed by Konus-Wind, the burst had the total fluence of 1.99(-0.46,+0.57)x10^-6 erg/cm2, and the 16-ms peak flux, measured from T0-0.008 s, of 3.09(-1.06,+1.28)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+0.064 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 = -0.67(-0.36,+0.46), the high energy photon index beta = -2.13(-0.85,+0.36), the peak energy Ep = 541(-204,+367) keV (pgstat = 33/45 dof). A power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) with alpha = -0.79(-0.42,+0.49) and Ep = 670(-240,+1097) keV fits this spectrum equally well (pgstat = 35/46 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/44722. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...