{
  "bibcode": "2006GCN..4529....1C",
  "body": "S. Campana (INAF-OAB), M. Perri (ASDC), P. Romano (INAF-OAB), D.N. Burrows\n(PSU), J. Norris (GSFC), K. Hurley (Berkeley) report:\n\n\"We have analyzed the first four orbits of XRT data from GRB 060116\n(Campana et al., GCN 4519). The GRB afterglow is detected at a mean count\nrate of 0.099+/-0.004 count/s during a 5545 s Photon Counting mode\nobservation. Close to the GRB afterglow (1.2 arcmin) there is a fainter\nsource (0.017+/-0.002 count/s) coincident with an M4 star. The best fit\nposition for the GRB afterglow is:\nRA(J2000) = 05h 38m 46.22s,\nDec(J2000) = -05d 26m 11.9s\nwith error radius 3.7 arcsec, less than 1 arcsec from the one reported\nin Campana et al. (GCN 4522) based on a shorter observation. This\nposition is also 1.5 arcsec from the source reported by Kocevski et al.\n(GCN 4528).\n\nThe X-ray light curve is fading and its decay law is consistent with a\npower-law with slope of -0.95+/-0.07 (90% confidence level). No strong\nflare activity is observed.\n\nThe X-ray spectrum can be fit with an absorbed power law model\nwith photon index of 2.1+/-0.3 and a column density of (8.1+/-2.5)E21\ncm-2, higher than the Galactic hydrogen column density in the direction \nof the burst (NH_gal=2.0E21 cm-2 at b=-19). The mean 0.5-10 keV unabsorbed\nflux is 9E-12 erg cm-2 s-1. Fixing the Galactic column density to\nthe above value we can constrain the GRB redshift to be z<3.2 or z>5.4\n(90% c.l., and NH(z)>4E21 cm-2).\n\nIf the burst continues to decay at the current rate we estimate an XRT\ncount rate of 2E-3 counts/s at T+24hr, which corresponds to an observed\n0.5-10 keV flux of ~3E-13 ergs cm-2 s-1.",
  "circularId": 4529,
  "createdOn": 1137449694000,
  "email": "campana@merate.mi.astro.it",
  "subject": "GRB 060116: XRT refined analysis",
  "submitter": "Sergio Campana at INAF-OAB  <campana@merate.mi.astro.it>",
  "eventId": "GRB 060116"
}