{
  "bibcode": "2006GCN..5767....1C",
  "body": "G. Cusumano (IASF-Pa INAF), T. Mineo (IASF-Pa INAF), V. Mangano (IASF-Pa \nINAF),\nB. Sbarufatti (IASF-Pa INAF) and T. Sakamoto (GSFC/ORAU)\nreport on behalf of the Swift XRT team:\n\nWe have analyzed the first 4 orbits of Swift-XRT data obtained for GRB\n061028 (trigger=235715, GCN 5762). The data consist of 100 s in Windowed\nTiming (WT) mode, starting 205 seconds after the BAT trigger and 8 ks\nin Photon Counting (PC) mode.\n\nUsing PC data we obtain a refined position of:\n\nRA(J2000) =  06h 28m 54.53s\nDec(J2000)= +46d 17' 55.20\"\n\nwith an estimated uncertainty radius of 3.9 arcsec (90% containment)\ntaking into account the new TELDEF files .  This location is 0.4 arcsec\nfrom the first XRT position (GCN 5762).\n\nThe light-curve shows a steep decay (alpha=3.9�0.4) up to the  end of the\nsecond orbit.  Data relative to the next two orbits show a detection at 3\nsigma level with a count rate of  (3�1)E-3 corresponding to a flux of\n1.5E-13 erg cm^-2 sec^-1, significantly higher than the model \nextrapolation.\n\nThe spectrum from all the WT data can be modeled with a\npower law of photon index Gamma = 1.4 � 0.1, with an absorbing\ncolumn of NH = (2.4�0.6)E21 cm^-2, significantly higher than the\nGalactic value of 1.37E21 cm^-2. The 0.2-10 keV unabsorbed flux\nduring the WT is 5.7E-10 erg cm^-2 sec^-1. The spectrum from\nthe PC data is softer than the WT spectrum: it can be modeled with a\npower-law of photon index Gamma = 2.4�0.4.\nAll errors are quoted at 90% confidence level.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 5767,
  "createdOn": 1162045510000,
  "email": "teresa.mineo@ifc.inaf.it",
  "subject": "GRB061028: XRT refined analysis",
  "submitter": "Teresa Mineo at INAF-IASFA  <teresa.mineo@ifc.inaf.it>",
  "eventId": "GRB 061028"
}