Konus-Wind observation of GRB 191227A
Abstract
The long-duration GRB 191227A (Fermi-GBM detection: The Fermi GBM team, GCN Circ. 26593; Swift-BAT detection: Melandri et al., GCN Circ. 26595; Stamatikos et al., GCN Circ. 26608; Fermi-LAT detection: Fana Dirirsa et al., GCN Circ. 26598) triggered Konus-Wind at T0=5970.414 s UT (01:39:30.414). The burst light curve shows a multi-peaked structure which starts at ~T0-27 s and has a total duration of ~52 s. The emission is seen up to ~10 MeV. The Konus-Wind light curve of this GRB is available at http://www.ioffe.ru/LEA/GRBs/GRB191227_T05970/ As observed by Konus-Wind, the burst had a fluence of 1.02(-0.08,+0.09)x10^-4 erg/cm2, and a 64-ms peak flux, measured from T0+8.096 s, of 1.86(-0.35,+0.36)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 = -0.70(-0.12,+0.13), the high energy photon index beta = -2.28(-0.16,+0.12), the peak energy Ep = 275(-26,+30) keV (chi2 = 102/97 dof). The spectrum near the maximum count rate (measured from T0+6.400 to T0+13.056 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 = -0.65(-0.18,+0.22), the high energy photon index beta = -2.25(-0.22,+0.15), the peak energy Ep = 266(-40,+46) keV (chi2 = 82/97 dof). All the quoted errors are at the 90% confidence level. All the quoted values are preliminary.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- December 2019
- Bibcode:
- 2019GCN.26614....1S