{
  "bibcode": "2017GCN.21235....1E",
  "body": "S.W.K. Emery (UCL-MSSL), S.R. Oates (Uni. of Warwick), S.D. Barthelmy\n(NASA/GSFC), A.P. Beardmore (U. Leicester), A.A. Breeveld (UCL-MSSL),\nD.N. Burrows (PSU), S. Campana (INAF-OAB), S.B. Cenko (NASA/GSFC),\nG. Cusumano(INAF-IASF PA), A. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB),\nV.D'Elia(ASDC), P.A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU),\nJ.A. Kennea (PSU), H.A. Krimm (CRESST/GSFC/USRA), N.P.M. Kuin (UCL-MSSL),\nA.Y. Lien (GSFC/UMBC), F.E. Marshall (NASA/GSFC), A. Melandri (INAF-OAB),\nB. Mingo (U. Leicester), J.A. Nousek (PSU), P.T. O'Brien (U. Leicester),\nJ.P. Osborne (U. Leicester), C. Pagani (U. Leicester), K.L. Page (U.Leicester),\nD.M. Palmer (LANL), M. Perri (ASDC), J.L. Racusin (NASA/GSFC), B. Sbarufatti\n(INAF-OAB/PSU), M.H. Siegel (PSU), G. Tagliaferri (INAF-OAB), E. Troja\n(NASA/GSFC/UMCP) report on behalf of the Swift team:\n\nThe Swift/UVOT performed a four-pointing follow up of the possible LAT source in\nthe error region of GW trigger G288732 (Omodei et al., LVC Circ. 21227). The\nobservations currently span from 62.8 ks to 86.3 ks after the LVC trigger. We detect\noptical sources in the XRT error circles of 'source 3', 'source 6' and 'source 7', but\nthese are also present in the SDSS catalogue and we do not find evidence of fading.\nAdditionally, the XRT error circle for 'source 5' is on the edge of the UVOT detector,\nbut we do not see any optical source in the error circle. We do not find any optical\nafterglow consistent with the LAT position or 'source 1', 'source 2' and 'source 4' of\nthe XRT follow up of G288732 (Evans et al., GCN Circ. 21233) in the UVOT exposures\nat more than 3 sigma.\n\nPreliminary 3-sigma upper limits using the UVOT photometric system\n(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the\nexposures are:\n\nXRT_source      Filter    T_start(s)  T_stop(s)  Exp(s)    Mag/3sigUL\n\n1       u          63081           85743          1737      > 20.8\n2       u          62802           85173          1764      > 20.5\n4       u          62942           86261          1710      > 20.4\n\nThe magnitudes in the table are not corrected for the Galactic extinction\ndue to the reddening of E(B-V) = 0.02 in the direction of the transient\n(Schlegel et al. 1998).",
  "circularId": 21235,
  "createdOn": 1497024835000,
  "email": "S.Oates@warwick.ac.uk",
  "subject": "LIGO/Virgo G288732: Swift/UVOT follow up of the possible LAT counterpart",
  "submitter": "Samantha Oates at U of Warwick  <S.Oates@warwick.ac.uk>",
  "eventId": "LIGO/Virgo G288732"
}