TITLE: GCN CIRCULAR NUMBER: 39001 SUBJECT: Konus-Wind detection of GRB 250117A DATE: 25/01/20 16:32:53 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 short-duration GRB 250117A (GECAM-B detection: Wang et al., GCN 38982; Swift/BAT-GUANO localization: DeLaunay et al., GCN 38988; SVOM/GRM detection: Wang et al., GCN 38994; IPN triangulation: Ridnaia et al., GCN 39000) triggered Konus-Wind at T0=73313.657 s UT (20:21:53.657).
The burst light curve shows a weak count rate increase (from ~T0-0.412 s to ~T0-0.288) followed by a bright, multi-peaked pulse, which starts at ~T0-0.126 s and has a duration of ~0.138 s.
The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB250117_T73313/
As observed by Konus-Wind, the burst had the total fluence of 7.70(-0.02,+2.44)x10^-7 erg/cm^2 and a 16-ms peak flux, measured from T0-0.008 s, of 1.87(-0.25,+0.64)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).
Since a major part of the burst emission was detected before the trigger time, the spectral analysis was performed using the KW 3-channel light curve data.
Modelling the KW 3-channel spectrum of the main pulse (measured from T0-0.126 s to T0+0.012 s) by a power law with exponential cutoff (CPL) model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep), yields alpha = 0.52 (-0.54, + 0.75) and Ep = 459(-62,+84) keV.
All the quoted errors are estimated at the 68% confidence level. All the presented results are preliminary.
View this GCN Circular online at https://gcn.nasa.gov/circulars/39001. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...