TITLE: GCN CIRCULAR NUMBER: 36659 SUBJECT: Konus-Wind detection of GRB 240607A DATE: 24/06/11 13:55:10 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 very bright, long-duration GRB 240607A (Fermi-GBM detection: The Fermi GBM team, GCN 36634; Dalessi, GCN 36637; Dalessi and Meegan, GCN 36641; BALROG localization: Preis et al., GCN 36635; AstroSat-CZTI detection: Waratkar et al., GCN 36638; IPN triangulation: Kozyrev at al., GCN 36650) triggered Konus-Wind at T0=39674.62 s UT (11:01:14.620).
The burst light curve shows a multipeaked structure which starts at ~T0-0.2 s and has a total duration of ~24.7 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/GRB240607_T39674/
As observed by Konus-Wind, the burst had a fluence of 1.03(-0.06,+0.05)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+10.960 s, of 3.02(-0.33,+0.34)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+29.440 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 = -0.94(-0.05,+0.05), the high energy photon index beta = -2.92(-0.42,+0.22), the peak energy Ep = 248(-13,+13) keV (chi2 = 111/98 dof).
The spectrum near the maximum count rate (measured from T0+10.752 to T0+11.264 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 = -0.21(-0.18,+0.19), the high energy photon index beta = -2.77(-0.37,+0.20), the peak energy Ep = 249(-24,+31) keV (chi2 = 54/46 dof).
All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
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