{
  "bibcode": "2007GCN..6167....1P",
  "body": "C. Pagani, J. L. Racusin, L. Vetere, D. Grupe, D. N. Burrows (PSU), report on \nbehalf of the Swift XRT team:\n\nWe have analysed the Swift-XRT Photon Counting data of GRB 070227 (GCN Circ. \n6156) from T+56ks to T+386ks (where T is the BAT trigger time). The candidate \nX-ray afterglow reported in GCN Circ. 6157 has faded from the initial count \nrate of ~ 0.01 counts/s to a count rate of 0.002 counts/s. \nUsing 39ks of PC data the refined XRT position is RA,Dec= 120.5805, -46.3135 \nwhich is:\n\nRA(J2000): 08h 02m 19.33s\nDec(J2000): -46d 18' 48.7\"\n\nwith an uncertainty of 4 arcseconds (90% containment).  This position is 47 \narcseconds from the refined BAT position given in GCN Circ. 6158 and 0.7 \narcseconds from the XRT position given in GCN Circ. 6157. \n\nThe light-curve shows an initial flat phase during the first 20ks of XRT \nobervations ending at about 80ks after the burst, followed by a decay that can \nbe fitted with a power law with index 0.9+/-0.2.\n\nThe spectral fit to the PC data is not very well constrained due to the low \nnumber of afterglow events.  The fit with an absorbed power law, applying \nC-statistics, gives a photon index of 2.9 (+0.8/-0.5) in the [0.3-10] keV \nband, and a column density of (0.57 +0.26/-0.18)e22 cm^-2 (compared with the \nGalactic value in this direction of 0.31e22 cm^-2).  \nThe average estimated unabsorbed 0.3-10 keV flux from T+56ks to T+386ks of XRT \nPhoton Counting observations was 3.6e-13 erg cm^-2 s^-1.\n\nThis Circular is an official product of the Swift XRT Team.",
  "circularId": 6167,
  "createdOn": 1173128867000,
  "email": "pagani@astro.psu.edu",
  "subject": "GRB070227: Swift-XRT refined analysis",
  "submitter": "Claudio Pagani at PSU/Swift-XRT  <pagani@astro.psu.edu>",
  "eventId": "GRB 070227"
}