GRB 231104A: Swift-XRT refined Analysis
Abstract
We have analysed 6.6 ks of XRT data for GRB 231104A, from 72 s to 34.5 ks after the BAT trigger. The data comprise 62 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The late-time light curve (from T0+10.9 ks) can be modelled with a power-law decay with a decay index of alpha=1.08 (+/-0.22). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.93 (+0.28, -0.27). The best-fitting absorption column is 7.9 (+1.1, -1.0) x 10^22 cm^-2, in excess of the Galactic value of 1.3 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 9.9 x 10^-11 (3.0 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 7.9 (+1.1, -1.0) x 10^22 cm^-2 Galactic foreground: 1.3 x 10^21 cm^-2 Excess significance: 12.5 sigma Photon index: 1.93 (+0.28, -0.27) If the light curve continues to decay with a power-law decay index of 1.08, the count rate at T+24 hours will be 0.017 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.7 x 10^-12 (5.0 x 10^-12) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01194500. This circular is an official product of the Swift-XRT team.
- Publication:
-
GRB Coordinates Network
- Pub Date:
- November 2023
- Bibcode:
- 2023GCN.34944....1K