TITLE: GCN CIRCULAR NUMBER: 36225 SUBJECT: GRB 240415A: Swift-XRT refined Analysis DATE: 24/04/22 07:22:59 GMT FROM: Phil Evans at U of Leicester pae9@star.le.ac.uk
P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:
We have analysed 5.4 ks of XRT data for GRB 240415A, from 3.3 ks to 26.8 ks after the BAT trigger. The data comprise 281 s in Windowed Timing (WT) mode with the remainder in Photon Counting (PC) mode.
The light curve can be modelled with a power-law decay with a decay index of alpha=0.97 (+/-0.09).
A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.18 (+/-0.16). The best-fitting absorption column is 2.2 (+/-0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.5 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.3 x 10^-11 (4.9 x 10^-11) erg cm^-2 count^-1.
A summary of the PC-mode spectrum is thus: Total column: 2.2 (+/-0.5) x 10^21 cm^-2 Galactic foreground: 2.5 x 10^20 cm^-2 Excess significance: 6.4 sigma Photon index: 2.18 (+/-0.16)
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01221874.
This circular is an official product of the Swift-XRT team.
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