TITLE: GCN CIRCULAR NUMBER: 43389 SUBJECT: Konus-Wind detection of GRB 260101A DATE: 26/01/13 15:31:48 GMT FROM: Dmitry Svinkin at Ioffe Institute <svinkin@mail.ioffe.ru> D. Svinkin, D. Frederiks, A. Lysenko, A. Ridnaia, A. Tsvetkova, M. Ulanov, and T. Cline on behalf of the Konus-Wind team, report: The long-duration GRB 260101A (Fermi-GBM detection: The Fermi GBM team, GCN 43284; Hristov and Meegan, GCN 43297; Swift-BAT detection: Cenko et al., GCN 43285; Markwardt et al., GCN 43354; SVOM-GRM detection: Yu et al., GCN 43292; GECAM-B detection: Wang et al., GCN 43294) triggered Konus-Wind at T0=3419.619 s UT (00:56:59.619). The burst light curve shows a multipeaked structure which starts at ~T0-26 s and has a total duration of ~30 s. The emission is seen up to ~1 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB260101_T03419/ As observed by Konus-Wind, the burst had the total fluence of 7.47(-0.65,+0.77)x10^-6 erg/cm2, and the 64-ms peak flux, measured from T0+0.210 s, of 1.95(-0.42,+0.44)x10^-6 erg/cm2/s (both in the 20 keV - 10 MeV energy range). Since the main fraction of burst counts was detected before the trigger, the spectral analysis was performed using the KW 3-channel light curve data. Modelling the KW 3-channel time-integrated spectrum (measured from T0-26.365 s to T0+3.168 s) by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), yields alpha = -1.50(-0.11,+0.13) and Ep = 176(-30,+45) keV. Modelling the KW 3-channel spectrum near the maximum count rate (measured from T0-5.757 s to T0+3.168 s) by the CPL model yields alpha = -1.44(-0.15,+0.20) and Ep = 129(-18,+25) keV. Assuming the redshift z=2.623 (de Ugarte Postigo et al., GCN 43287) and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014), we estimate the following rest-frame parameters: the isotropic energy release E_iso is 1.21(-0.11,+0.12)x10^53 erg, the peak luminosity L_iso is 1.15(-0.25,+0.26)x10^53 erg/s, the rest-frame peak energy of the time-averaged spectrum Ep,i,z is 637(-109,+162) keV and the spectrum near the maximum count rate Ep,p,z is 467(-65,+90) keV. With the obtained estimates, GRB 260101A is inside 68% prediction bands for both the 'Amati' and the 'Yonetoku' relations derived for the sample of >300 long KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021), see http://www.ioffe.ru/LEA/GRBs/GRB260101_T03419/GRB260101A_rest_frame.pdf 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/43389. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...