{
  "bibcode": "2019GCN.25939....1O",
  "body": "S. R. Oates (Uni. of Warwick), N. P. M. Kuin (UCL-MSSL), A. A. Breeveld\n(MSSL-UCL),\nF. E. Marshall (NASA/GSFC), P. Brown (TAMU), C. Gronwall (PSU),\nM. J. Page (UCL-MSSL), M. De Pasquale (Istanbul U.), M. H. Siegel (PSU),\nA. D'Ai (INAF-IASFPA), P. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC),\nA. P. Beardmore (U. Leicester), D. N. Burrows (PSU), S. Campana (INAF-OAB),\nS. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA), V. D'Elia(ASDC),\nP. A. Evans (U. Leicester), P. Giommi (ASI), D. Hartmann (Clemson U.),\nJ. A. Kennea (PSU), N. J. Klingler (PSU), H. A. Krimm (NSF), A. Y. Lien\n(GSFC/UMBC),\nD. B. Malesani (DTU Space), A. Melandri (INAF-OAB), J. A. Nousek (PSU),\nP. T. O'Brien (U. Leicester), J. P. Osborne (U. Leicester), C. Pagani (U.\nLeicester),\nK. L. Page (U.Leicester), D.M. Palmer (LANL), M. Perri (ASDC),\nJ. L. Racusin (NASA/GSFC), T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU),\nG. Tagliaferri (INAF-OAB), A. Tohuvavohu (U Toronto), and\nE. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:\n\nSwift UVOT reobserved the field of Swift J221951-484240 (Oates et al., GCN\nCirc.\n25901), a candidate transient found in the UVOT search results of the LVC\nevent\nS190930t (LIGO/VIRGO Collaboration GCN Circ. 25876).\n\nA search of this source in various catalogs shows only a weak IR source,\nhowever\nSwift observed a blue source which maintained its brightness in the second\nobservation\nsuggesting that this is not a flaring M-dwarf.\n\nThe second tranche of observations began at 2019-10-02 16:14:34 UT 179ks\nafter\nthe LVC trigger.\n\nPreliminary detections using the UVOT photometric system (Breeveld et\nal. 2011, AIP Conf. Proc. 1358, 373) are:\n\nFilter   Exp(s)        Mag\nv         79        > 18.7\nb         79        19.68+\\-0.36\nu         79        18.57+\\-0.21\nw1       157        17.95+\\-0.16\nm2       249        17.91+\\-0.15\nw2       315        18.11+\\-0.13\n\nIn the combined 1.1 ks of data collected so far, no X-ray source is\ndetected to a 3-sigma upper limit of 9.9e-3 count s^-1 (equivalent to an\nobserved flux ~4e-13 erg cm^-2 s^-1, assuming a typical power-law\nspectrum).\n\nThis new blue transient requires spectroscopy for further identification,\nand we\n encourage spectroscopic followup of this transient.\n\nThis circular is an official product of the Swift team.",
  "circularId": 25939,
  "createdOn": 1570126317000,
  "email": "npkuin@gmail.com",
  "subject": "LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240",
  "submitter": "Paul Kuin at MSSL  <npkuin@gmail.com>",
  "eventId": "LIGO/Virgo S190930t"
}