{
  "bibcode": "2019GCN.24296....1B",
  "body": "LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search\n\nA. A. Breeveld (MSSL-UCL), N. P. M. Kuin (UCL-MSSL), F. E. Marshall (NASA/GSFC),  P. Brown (TAMU),\nS. R. Oates (Uni. of Warwick), M. H. Siegel (PSU), M. de Pasquale (Uni. of Istanbul),\nS. D. Barthelmy (NASA/GSFC), A. Y. Lien (GSFC/UMBC), \nD. M. Palmer (LANL), T. Sakamoto (AGU), A. P. Beardmore (U. Leicester),\nD. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC),\nG. Cusumano (INAF-IASF PA), A. D'Ai (INAF-IASFPA), \nP. D'Avanzo (INAF-OAB), V. D'Elia(ASDC), S. Emery (UCL-MSSL), \nP. A. Evans (U. Leicester), P. Giommi (ASI), C. Gronwall (PSU), \nD. Hartmann (Clemson U.), J. A. Kennea (PSU), H. A. Krimm (NSF), \nA. Melandri (INAF-OAB), B. Mingo (U. Leicester), J. A. Nousek (PSU), \nP. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U. Leicester), \nK. L. Page (U.Leicester), M. Perri (ASDC), \nJ. L. Racusin (NASA/GSFC), B. Sbarufatti (INAF-OAB/PSU),\nG. Tagliaferri (INAF-OAB), A. Tohuvavohu (PSU),\nE. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:\n\nWe report a candidate transient found in the UVOT search results of the\nLVC event S190425z (LIGO/VIRGO Collaboration GCN Circ. 24168). \n\nOn 2019-04-26 at 18:49:22 UT Swift UVOT took a 66.8 s exposure in the u band with \nexposure ID uu577997367I (target ID 07016575) which shows a new source when compared with\narchived DSS images. The new source is not listed in the Gaia DR1, 2MASS or GSC2.3 \ncatalogs or Pan-STARRS and is not listed as a minor planet. \n\nThe position is: \nRA = 255.5800 deg\nDec = -12.48562 deg\nwhich is RA=17:02:19.2, Dec=-12:29:08.2 (J2000).\n\nThe magnitude using the UVOT photometric system  (Breeveld et al. 2011, AIP \nConf. Proc. 1358, 373) is u=17.74 +/- 0.18 mag (Vega).\n\nNo source is found at this position in the XRT, with a 3-sigma upper limit of  \n5.8 x 10^-2 ct s^-1, which corresponds to a 0.3-10 keV observed flux of \n2.5 x 10^-11 erg cm^-2 s^-1.\n\nAt this position, the distance estimate from the LALInference sky map has a mean \nof 132 Mpc with a sigma of 35 Mpc. \n\nThere is a bright galaxy in the 2MPZ catalogue (Bilicki et al., 2014) 2MPZ\nJ17021587-1228210 at 68 arcsec (z = 0.022, D = 99 Mpc, abs K magnitude = 12.4),\nwhich is 33 kpc away in projection. A second galaxy, 2MPZ J17020235-1229511 lies\n250 arcsec away from the UVOT position. This galaxy has a distance of 106 Mpc in\nthe 2MPZ catalogue so the projected offset is 128 kpc. At the distance of these\ngalaxies, the absolute U magnitude would be -17.3, which is brighter than AT 2017gfo at\nt ~ 2 days.\n\nThis circular is an official product of the Swift team.",
  "circularId": 24296,
  "createdOn": 1556390334000,
  "email": "mhs18@psu.edu",
  "subject": "LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search",
  "submitter": "Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>",
  "eventId": "LIGO/Virgo S190425z"
}