GRB 240712A: Swift-XRT refined Analysis

We have analysed 1.7 ks of XRT data for the Swift/BAT-detected burst GRB 240712A, from 152 s to 5.3 ks after the Swift/BAT trigger. The data are entirely in Photon Counting (PC) mode. Using 1421 s of PC mode data and 2 UVOT images, we find an enhanced XRT position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 122.33591, -37.08814 which is equivalent to: RA (J2000): 08h 09m 20.62s Dec(J2000): -37d 05' 17.3" with an uncertainty of 3.2 arcsec (radius, 90% confidence). This position is 103 arcsec from the Swift/BAT position. The light curve can be modelled with a power-law decay with a decay index of alpha=0.9 (+/-0.4). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.5 (+1.1, -1.0). The best-fitting absorption column is 2.6 (+2.5, -1.7) x 10^22 cm^-2, consistent with the Galactic value of 8.9 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 9.0 x 10^-11 (1.4 x 10^-10) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 2.6 (+2.5, -1.7) x 10^22 cm^-2 Galactic foreground: 8.9 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 1.5 (+1.1, -1.0) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/01242223. This circular is an official product of the Swift-XRT team.