{
  "subject": "GRB 060121: Swift XRT refined analysis",
  "eventId": "GRB 060121",
  "bibcode": "2006GCN..4565....1M",
  "createdOn": 1137955598000,
  "circularId": 4565,
  "submitter": "Pat Romano at OAB-Swift  <romano@merate.mi.astro.it>",
  "email": "romano@merate.mi.astro.it",
  "body": "V. Mangano, V. La Parola, T. Mineo (INAF-IASFPA), P. O'Brien (UL),\nP. Romano (INAF-OAB), D.N. Burrows (PSU), M. Chester (PSU),\nL. Angelini (GSFC) on behalf of the Swift XRT team:\n\nThe Swift XRT instrument began observing the HETE-discovered GRB 050121\n(Arimoto et al., GCN 4550; Prigozhin et al., GCN 4551) at 01:21:37 UT\non 22 January 2006 (Mangano et al., GCN 4560) 10.6 ks after the burst.\n\nFurther analysis of the first 5 ks of XRT data of GRB 060121\nspanning three orbits (Mangano et al., GCN 4560)\nrevealed that the source is fading with a power law decay index\nof -1.08 + / - 0.24.\n\nThe average spectrum is well fitted by an absorbed power law\nmodel with a photon index of 2.07 + / - 0.25 (90% confidence level).\nThe best fit absorption column of (7.8 + / - 4.5)e20 cm^-2 is\nslightly in excess of the Galactic absorption column of 1.7e20 cm^-2.\nThe average unabsorbed 0.2-10 keV flux in the time range\n10.6 - 22 ks after the trigger is at the level of\n4.6e-12 ergs cm^-2 s^-1.\nThe predicted flux at 24 hours after the trigger is at the\nlevel of 6.8e-13 ergs cm^-2 s^-1 (corresponding to a count rate\nof about 1.1e-2 counts/s).\nNew observations are being performed. \n\nAccording to NED, the nearest two galaxies with known redshifts\nare SDSS J091016.39+453819.9 and SDSS J091023.53+454159.8 with a\nredshift of 0.154357 and 0.154272, respectively.\nThey are 4.5 and 6 arcmin from the Swift GRB position\n(Mangano et al., GCN 4560)."
}