TITLE: GCN CIRCULAR NUMBER: 6143 SUBJECT: GRB070224: Swift-XRT Refined Analysis DATE: 07/02/25 05:11:37 GMT FROM: Judith Racusin at PSU J. Racusin, J. Kennea, D. Morris, C. Pagani, L. Vetere (PSU) report on behalf of the Swift-XRT team: We have analysed the first 3 orbits of Swift-XRT data available for GRB 070224 (Racusin et al., GCN 6137), consisting of 45 s of Windowed Timing (WT) mode data, and ~1.7 ks of Photon Counting (PC) mode data. The refined XRT position from the PC data is RA,Dec= 179.02684, -13.3304 which is: RA(J2000) = 11h 56m 06.44s Dec(J2000) = -13d 19' 49.5" with an uncertainty of 3.8 arcsec (90% containment). This is 5.0 arcseconds from the initial position reported in GCN 6137, and 134 arcseconds from the BAT refined position (Tueller et al., GCN 6141). The preliminary 0.3-10.0 keV lightcurve shows a steep fading behavior in the first orbit with a decay index of 3.1 +/- 0.2. The data in the subsequent orbits provides only an upper limit. It is not currently possible to determine if there has been a break to a flatter decay. The WT spectrum is fit by an absorbed power-law with a photon index of 2.8 +/- 0.6. The absorption is at a level of 6.0e20 cm^-2, consistent with Galactic absorption along the line of sight (4.1e20 cm^-2). The average 0.3-10 keV unabsorbed flux of the WT spectrum is 2.1e-10 ergs cm^-2 s^-1. This circular is an official product of the Swift-XRT team.