TITLE: GCN CIRCULAR NUMBER: 13406 SUBJECT: GRB 120701A: Swift-XRT afterglow detection and analysis DATE: 12/07/03 12:20:14 GMT FROM: Phil Evans at U of Leicester P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team: We have analysed 19 ks of XRT data for GRB 120701A (Barthelmy et al. et al. GCN Circ. 13404), from 61 s to 58.8 ks after the BAT trigger. The data comprise 69 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. We find an uncatatalogued, fading X-ray source inside the BAT error circle. Using 7344 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 = 80.34740, -58.54973 which is equivalent to: RA (J2000): 05h 21m 23.38s Dec(J2000): -58d 32' 59.0" 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=1.078 (+0.031, -0.030). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 2.06 (+0.22, -0.21). The best-fitting absorption column is 1.6 (+0.6, -0.5) x 10^21 cm^-2, in excess of the Galactic value of 2.5 x 10^20 cm^-2 (Kalberla et al. 2005). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (5.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Total column: 1.6 (+0.6, -0.5) x 10^21 cm^-2 Galactic foreground: 2.5 x 10^20 cm^-2 Excess significance: 4.0 sigma Photon index: 2.06 (+0.22, -0.21) The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00525477. This circular is an official product of the Swift-XRT team.