{
  "bibcode": "2006GCN..5733....1G",
  "body": "C. Guidorzi, P. Romano (Univ Bicocca & INAF-OAB), A. Moretti (INAF-OAB)\non behalf of the Swift-XRT team:\n\nWe have analysed the first 3 orbits of Swift-XRT data of GRB 061019\n(Guidorzi et al., GCN Circ. 5728). The data set consists of 6.5 ks in\nPhoton Counting (PC) mode.\n\nWe derived an XRT refined position of:\n\nRA(J2000)  = 06h 06m 30.73s\nDec(J2000) = 29d 34' 10.5''\n\nwith an estimated error radius of 6.7 arcsec (90% containment, including\nboresight uncertainties). This lies 4.2 arcsec from the preliminary XRT\nposition (Guidorzi et al., GCN Circ. 5729) and 88 arcsec from the\nground-refined BAT position (Sakamoto et al., GCN Circ. 5732).\nThe XRT refined position is still within the BAT error circle.\nThe K-band candidate reported by Covino et al. (GCN Circ. 5730) lies\nwithin the refined XRT error circle, 3.2 arcsec from our new position.\n\nThe X-ray lightcurve shows an initial slope of 0.7 +/- 0.4, with possible\nbreak around 10^4 s after the burst to an almost flat decay.\nAlternatively, it can be fit with a single power law with slope 0.56 +- \n0.10.\nFurther data will help clarify this ambiguity.\n\nThe time-averaged spectrum (from T+2.8 ks to T+17 ks) can be fit with an\nabsorbed power-law with a photon index of 2.1 +/- 0.3 (90%) and an \nabsorption\ncolumn of (9 +/- 2)e21 cm^-2 (90%), significantly in excess of the Galactic\nvalue in the direction of the burst (4.8e21 cm^-2).\nThe mean observed (unabsorbed) flux in the 0.3-10 keV energy band is\n4.2e-12 (9.2e-12) erg cm^-2 s^-1.\n\nAssuming the single power-law decay, the count rate at T+24 h\nis predicted to be 1.6e-2 cts s^-1, corresponding to an unabsorbed\n0.3-10 keV flux of 2.2e-12 erg cm^-2 s^-1.\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 5733,
  "createdOn": 1161274769000,
  "email": "cristiano.guidorzi@brera.inaf.it",
  "subject": "GRB061019: Swift XRT refined analysis",
  "submitter": "Cristiano Guidorzi at INAF-OAB  <cristiano.guidorzi@brera.inaf.it>",
  "eventId": "GRB 061019"
}