GCN Circular 14788
A. Melandri (INAF/OAB) and S. T. Holland (STScI) report on behalf of the Swift-XRT team: We have analysed 15 ks of XRT data for GRB 130605A (Holland et al. GCN Circ. 14773), from 78 s to 58.5 ks after the BAT trigger. The data comprise 385 s in Windowed Timing (WT) mode (the first 8 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. Using 6133 s of PC mode data and 5 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 = 134.53571, -33.46152 which is equivalent to: RA (J2000): 08h 58m 08.57s Dec(J2000): -33d 27' 41.5" with an uncertainty of 1.8 arcsec (radius, 90% confidence). The light curve can be modelled with a power-law decay with a decay index of alpha=1.23 (+/-0.05). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 2.3 (+0.5, -0.3). The best-fitting absorption column is 2.35 (+1.96, -0.16) x 10^21 cm^-2, consistent with the Galactic value of 2.2 x 10^21 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 2.7 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 2.35 (+1.96, -0.16) x 10^21 cm^-2 Galactic foreground: 2.2 x 10^21 cm^-2 Excess significance: <1.6 sigma Photon index: 2.3 (+0.5, -0.3) If the light curve continues to decay with a power-law decay index of 1.23, the count rate at T+24 hours will be 9.4 x 10^-4 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.6 x 10^-14 (4.7 x 10^-14) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00557508. This circular is an official product of the Swift-XRT team.