{
  "bibcode": "2007GCN..6214....1L",
  "body": "V. La Parola, T. Mineo, B. Sbarufatti, V. Mangano, G. Cusumano\n(INAF-IASF Pa)\nreport on behalf of the Swift XRT team:\n\nWe have analysed the first two orbits of Swift-XRT data on GRB 070318\n(Cummings, et al., GCN Circ. 6210), with a total exposure of 427 s\nseconds\nin Window Timing (WT) mode and 33.4 ks seconds in Photon Counting (PC)\nmode. This provides a refined XRT position at RA,Dec=48.4870,-42.9454\nwhich is:\n\nRA (J2000) = 03h 13m 56.9s\nDec(J2000) = -42d 56m 43.6s\n\nwith an estimated error radius of 3.5 arcseconds (90% confidence).\nThis\nposition is 16.8 arcseconds from the BAT refined position (Cummings,\net al., GCN 6212), 6.2 arcseconds from the initial XRT position, and\n2.9\narcseconds from the UVOT optical candidate (Cummings, et al., GCN\nCirc.\n6210).\n\nThe 0.3-10 keV X-ray light curve presents a bright flare peaking at\nabout 280 s from the trigger and a second fainter peak\nat 200 s. The underlying light curve between 70 s and 7.5 ks\ncan be fit with a simple power-law with a decay slope of 1.11 � 0.02.\n\nThe X-ray spectrum from the XRT/WT data covering up to the beginning\nof\nthe bright flare is well fit by an absorbed power-law with a photon\nindex\nof 1.4�0.1 and column density of (1.5�0.7)E21 cm**-2, higher\nthan the Galactic column density in the direction of the source\n(2.5E20 cm**-2). The unabsorbed 0.3-10 keV flux for this spectrum is\n1.3E-9 erg/cm**2/s. The XRT/WT spectrum of the bright flare and the\nXRT/PC spectrum are modelled by an absorbed power law\nwith photon index of 1.9�0.1 and column density of (1.3�0.3)E21\ncm**-2.\nThe unabsorbed 0.3-10 keV flux of the bright flare is 8.2E-10\nerg/cm**2/s\nand the one relative to the PC spectrum is 1.0E-10 erg/cm**2/s.\n\nAssuming the X-ray emission continues to decline at the same rate, we\npredict a 0.3-10 keV XRT count rate of 5E-3 count/s at T+48hr, which\ncorresponds to an observed 0.3-10 keV flux of 2.5e-13 erg/cm**2/s.\n\nThis circular is an official product of the Swift XRT Team.",
  "circularId": 6214,
  "createdOn": 1174238214000,
  "email": "teresa.mineo@ifc.inaf.it",
  "subject": "GRB070318: Swift-XRT refined analysis",
  "submitter": "Teresa Mineo at INAF-IASFA  <teresa.mineo@ifc.inaf.it>",
  "eventId": "GRB 070318"
}