{
  "subject": "LIGO/Virgo G211117: Further Swift-XRT sources",
  "eventId": "LIGO/Virgo G211117",
  "bibcode": "2016GCN.18834....1E",
  "createdOn": 1452072826000,
  "circularId": 18834,
  "submitter": "Phil Evans at U of Leicester  <pae9@leicester.ac.uk>",
  "email": "pae9@leicester.ac.uk",
  "body": "P.A. Evans (U. Leicester), J.A. Kennea (PSU), S.D. Barthelmy\n(NASA/GSFC), D.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko\n(NASA/GSFC), N. Gehrels (NASA/GSFC), P. Giommi (ASI), F.E. Marshall\n(NASA/GSFC), J.A. Nousek (PSU), P.T. O'Brien (U. Leicester), J.P.\nOsborne (U. Leicester), D.M. Palmer (LANL), M. Perri (ASDC), J.L.\nRacusin (NASA/GSFC), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB)\nreport on behalf of the Swift team:\n\nSwift has performed a series of 76 observations of galaxies (from the\nGWGC catalogue) within the aLIGO error region for the aLIGO trigger\nG211117, using the 'bayestar' GW localisation map. The observations\ncurrently span from 140 ks to 914 ks after the aLIGO trigger, and cover\n8.6 sq degrees on the sky (corrected for overlaps).\n\nSince the last Swift GCN, we have detected 2 X-ray sources, these are\neither new detections, or have been given a higher 'rank' than in the\nlast circular. Each source is assigned a rank of 1-4 which describes\nhow likely it is to be related to the GW trigger, with 1 being the most\nlikely and 4 being the least likely. The ranks are described at\nhttp://www.swift.ac.uk/ranks.php.\n\nWe have found:\n\n  * 0 sources of rank 1\n  * 0 sources of rank 2\n  * 1 source of rank 3\n  * 1 source of rank 4\n\nIn addition, we observed the location of the source PS15dqa (from\nSmartt et al., GCN Circ. 18824), an optical transient in NGC 1156 at a\ndistance of just 7 Mpc. No X-ray emission was detected at the location\nof PS15dqa to a 3-sigma upper limit of 4.1e-3 ct/sec, corresponding to\na flux of 1.8e-13 erg/cm^2/s.\n\nWe assumed a power-law spectrum with NH=3e20 cm^2, and photon index\n(Gamma)=1.7\n\n\nRANK 3 sources\n==============\n\nThese are uncatalogued X-ray sources, however they are not brighter\nthan previous upper limits, so do not stand out as likely counterparts\nto the GW trigger.\n  \n  Source 53:\n  =============\n    RA: \t 44.9257 ( = 02h 59m 42.17s) J2000\n    Dec:\t +25.2129 ( = +25d 12' 46.4\") J2000\n    Error:\t +5.8 (arcsec, radius, 90% confidence).\n    Peak Rate:\t 1.5e-03 +/- 7.9e-04 ct/sec (0.3-10 keV)\n    Peak Flux:\t 6.3e-14 +/- 3.4e-14 erg cm^-2 s^-1 (0.3-10 keV)\n    RASS UL:\t 3.0e-02 ct/sec, 3-sigma, converted to XRT (0.3-10 keV)\n\n       so the source is not above the RASS 3-sigma upper limit.\n    There is no evidence for fading.\n    There is 1 GWGC galaxy within 200 kpc of the source.\n\n\nRANK 4 sources\n==============\n\nThese are catalogued X-ray sources, showing no signs of outburst\ncompared to previous observations, so they are not likely to be related\nto the GW trigger.\n  \n  Source 54:\n  =============\n    RA: \t 202.5319 ( = 13h 30m 7.66s) J2000\n    Dec:\t -20.9364 ( = -20d 56' 11.0\") J2000\n    Error:\t +6.0 (arcsec, radius, 90% confidence).\n    Peak Rate:\t 2.0e-02 +/- 7.3e-03 ct/sec (0.3-10 keV)\n    Peak Flux:\t 8.5e-13 +/- 3.1e-13 erg cm^-2 s^-1 (0.3-10 keV)\n    Cat Source:  1SXPS J133007.7-205619 in the 1SXPS catalogue\n    Separation:  8.4\" from the XRT source\n    Cat Rate:\t 1.6e-02 +/- 1.6e-03 ct/sec (0.3-10 keV)\n    Cat Flux:\t 6.8e-13 +/- 6.9e-14 erg cm^-2 s^-1 (0.3-10 keV)\n       so the source  is 0.5-sigma above the catalogued flux.\n    There is no evidence for fading.\n    There is 1 GWGC galaxy within 200 kpc of the source.\n    A SIMBAD object `[RKV2003] QSO J1330-2056 abs 0.84992' is 5.3\"\naway.\n    There is 1 2MASS object within the source's 3-sigma error radius.\n\nThis circular is an official product of the Swift team."
}