{
  "bibcode": "2016GCN.19904....1D",
  "body": "A. D'A�  (INAF-IASFPA), V. D'Elia (ISDC), J. Cummings (GSFC/UMBC),\nB. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), T.G.R. Roegiers (PSU),\nS.L. Gibson (U. Leicester), J.P. Osborne (U. Leicester),\nK.L. Page (U. Leicester) and P.A. Evans (U. Leicester)\nreport on behalf of the Swift-XRT team:\n\nSwift-XRT has performed follow-up observations of the Fermi/GBM (Veres \net al., GCN Circ. 19901)\nand Fermi/LAT (Racusin et al., GCN Circ. 19902) detected burst GRB \n160910A in a series of 4 observations\ntiled on the sky. The total exposure time is 5 ks, distributed over 4 \ntiles.\nThe data were collected between T0+35 ks and T0+47 ks, and are entirely \nin Photon Counting (PC) mode.\n\nAn uncatalogued X-ray source is detected and is above the RASS limit, \nand is therefore likely the GRB afterglow.\nThe position of this source is RA, Dec.=221.4423, 39.0668 which is \nequivalent to:\n\nRA (J2000)   = 14h45m46.16s\nDec (J2000) = +39:04:00.64\n\nwith an uncertainty of 4.3 arcsec (radius, 90% confidence).\nThis position is 0.34 deg from the Fermi/LAT position and 0.6 deg from \nthe GBM position.\nThe light curve built with the data collected so far is consistent with \na constant source of mean\ncount rate (1.0 +/- 0.1)e-01 ct/sec. More data are required to search \nfor a fading behaviour.\n\nA spectrum formed from the PC mode data can be fitted with an absorbed\npower-law with a photon spectral index of 1.7 (+0.6, -0.6).\nThe best-fitting absorption column is  1.3 (+1.7, -1.3) x 10^21 cm^-2,\nconsistent with the Galactic value of 1.0 x 10^20 cm^-2 (Willingale et \nal. 2013).\nThe [absorbed] unabsorbed 0.3-10 keV flux is 5.1 (+1.6, -1.0)e^-10 erg \ncm^-2 s^-1 [4.7 (+2.1, -1.3) e-10 erg cm^-2 s^-1].\n\nThis circular is an official product of the Swift-XRT team.",
  "circularId": 19904,
  "createdOn": 1473606290000,
  "email": "antonino.dai@ifc.inaf.it",
  "subject": "GRB 160910A: Swift-XRT afterglow detection",
  "submitter": "Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>",
  "eventId": "GRB 160910A"
}