{
  "bibcode": "2008GCN..7951....1S",
  "body": "R.L.C. Starling (U. Leicester) and P. Schady (MSSL-UCL) report, on behalf \nof the Swift XRT team:\n\nWe have analysed the first 4 orbits of Swift XRT data (from T0+64s to \nT0+17.8 ks) for GRB 080707 (trigger=316204, Schady et al., GCN Circ. \n7947).\n\nUsing 1482 seconds of overlapping XRT Photon Counting (PC) mode and UVOT \ndata, we find an updated astrometrically corrected X-ray position (using \nthe XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 \ncatalogue): RA, Dec = 32.61860, 33.10983 deg which is equivalent to:\n \nRA(J2000) = 02 10 28.46 \nDec(J2000)= +33 06 35.4 \n\nwith an uncertainty of 1.5 arcseconds (radius, 90% confidence). This \nposition lies 1.35 arcseconds from the optical counterpart reported in \nClemens et al. (GCN Circ. 7948).\n\nThe light curve can be fit by an initial steep decay followed by a shallow \nplateau phase. The final orbit of data so far collected may indicate a \nfurther break to a steeper slope, but this is not required by the fit. \nA  singly broken power law gives alpha1=5.6+1/-0.8, Tbk=145+17/-13 and \nalpha2=0.35+0.06/-0.07. \nA doubly broken power law model gives the following parameters: \nalpha1=5.5+0.9/-0.8, Tbk1=151+6/-15s, alpha2=0.2+0.1/-0.5, \nTbk2=5300+5400/-4200s and alpha3=0.7+0.6/-0.3.\n\nThe PC mode spectrum comprising 1.64 ks of data from the latter part of \norbit 1 and from orbit 2 (T0+96s - T0+6384s) is well fit with a power law \nof photon index Gamma=2.1+0.4/-0.5 (90%) absorbed by the Galactic column \nof 6.99E+20 cm^-2 (Kalberla et al. 2005) and by a column at the inferred \nredshift of the host galaxy (z=1.23, Fynbo et al. GCN Circ. 7949) which \ncan only be constrained to be nH<1.23e22 cm^-2. The 0.3-10 keV observed \n(unabsorbed) flux is 5.4e-12 (6.73-12) erg/cm^2/s, corresponding to a \ncount rate of 0.12 count/s, hence the observed count rate to flux \nconversion is 1 count/s = 4.5e-11 erg/cm^2/s.\n\nThe predicted count rate at T0+24h is 0.011 counts/s, assuming a decay \nrate of alpha=0.7 from the doubly broken power law model.\n\nThis is an official product of the Swift XRT team.",
  "circularId": 7951,
  "createdOn": 1215462947000,
  "email": "rlcs1@star.le.ac.uk",
  "subject": "GRB 080707: Swift XRT refined analysis",
  "submitter": "Rhaana Starling at U of Leicester  <rlcs1@star.le.ac.uk>",
  "eventId": "GRB 080707"
}