{
  "bibcode": "2006GCN..5018....1M",
  "body": "V. Mangano (INAF-IASFPA), E. Troja (INAF-IASFPA),\nD. N. Burrows (PSU) report on behalf of the Swift XRT Team:\n\nWe have analyzed the first orbit data of GRB060428A\n(Mangano et al 2006, GCN 5014).\nThe XRT data set consists of 39 s exposure in Windowed\nTiming (WT) mode followed by 1670 s exposure in Photon\nCounting (PC) mode.\n\nThe refined position of the source is\n\n    RA  (2000) =  08h 14m 10.98s \n    Dec (2000) = -37d 10' 10.3\"\n\nwith an uncertainty of 3.6 arcsec (90% confinement).\nThis position is only 1.5 arcsec from the onboard\ndetected position (Mangano et al 2006, GCN 5014).\n\nThe 0.2-10 keV X-ray light curve shows an initial very\nfast decay with slope -6.3 +/- 0.4, a break at 144 +/- 6 s\nfrom the trigger and a flattening with a decay slope\nof -0.11 +/- 0.03. A small flare with a gaussian profile\nis present at 676 +/- 56 s after the trigger.\n\nThe WT and PC spectra were fitted separately with an\nabsorbed power law model and showed photon indices of\n3.2 +/- 0.4 and 1.9 +/- 0.2, respectively (90% confidence level).\nThe WT spectrum, covering the time interval 77-116 s, mostly\naccounts for the pre-break phase of the light curve.\n\nBoth spectra are highly absorbed, but do not show evidence of\nan absorption column in excess with respect to the Galactic\nvalue of 8.5 x 10^21 cm^-2.\nThe 0.2-10 keV unabsorbed fluxes of the two spectra are\n2.9 x 10^-9 and 7.6 x 10^-11 erg cm^-2 s^-1, respectively.\n\nIf decaying at the present rate the source will be at the\nflux level of 2.7 x 10^-11 erg cm^-2 s^-1 (corresponding to\na count rate level of 0.18 counts s^-1) after one day.\n\nThis Circular is an official product of the Swift XRT Team.",
  "circularId": 5018,
  "createdOn": 1146221133000,
  "email": "vanessa@ifc.inaf.it",
  "subject": "GRB060428A: Swift XRT Team refined analysis",
  "submitter": "Vanessa Mangano at INAF-IASFPA  <vanessa@ifc.inaf.it>",
  "eventId": "GRB 060428A"
}