{
  "bibcode": "2020GCN.27153....1O",
  "body": "S. R. Oates (U. of Birmingham),  K. L. Page (U.Leicester), A. A. Breeveld (MSSL-UCL),\nP. Brown (TAMU), M. De Pasquale (Istanbul U.), C. Gronwall (PSU), N. P. M. Kuin (UCL-MSSL),\nF. E. Marshall (NASA/GSFC), M. J. Page (UCL-MSSL),  M. H. Siegel (PSU), A. D'Ai (INAF-IASFPA),\nP. D'Avanzo (INAF-OAB), S. D. Barthelmy (NASA/GSFC), A. P. Beardmore (U. Leicester),\nD. N. Burrows (PSU), S. Campana (INAF-OAB), S. B. Cenko (NASA/GSFC), G. Cusumano (INAF-IASF PA),\nV. D���Elia (ASDC), P. 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 (GSFC/UMBC),\nD. B. Malesani (DTU Space), A. Melandri (INAF-OAB), J. A. Nousek (PSU), P. T. O'Brien (U. Leicester),\nJ. P. Osborne (U. Leicester), C. Pagani (U. Leicester), D. M. Palmer (LANL), M. Perri (ASDC),\nJ. L. Racusin (NASA/GSFC),  T. Sakamoto (AGU), B. Sbarufatti (INAF-OAB/PSU), G. Tagliaferri (INAF-OAB),\nA. Tohuvavohu (U Toronto), and E. Troja (NASA/GSFC/UMCP) report on behalf of the Swift team:\n\nWe report Swift/UVOT and XRT follow-up observations of ZTF20aamvmzj (AT2020cja; Kasliwal et al.,\nGCN Circ. 27051) found by Zwicky Transient Facility during the search for the EM counterpart\nof the LVC event S200213t (LIGO/VIRGO Collaboration GCN Circ. 27042). This object was also\nobserved by Lulin (Li et al., GCN Circ. 27082) and spectroscopically by DBSP\n(Ho et al., GCN Circ. 27074). \n\nSwift/UVOT and XRT observations began 6.7 days after the LIGO/VIRGO trigger (LIGO/VIRGO \nCollaboration GCN Circ. 27042). We detect ZTF20aamvmzj in the u and UV filters only. In the\nfollowing we give preliminary magnitudes using the UVOT photometric system (Breeveld et al. \n2011, AIP Conf. Proc. 1358, 373):\n\nFilter   T_start(s)   T_stop(s) Exp(s)     Mag\n\nv      577293     588978    228      >19.2\nb      576882\t  588576    236      >19.92\nu      576797\t  588492    236      19.05 +/- 0.27\nw1     576633\t  588408    472      19.46 +/- 0.30\nm2     577377\t  583756    753      19.82 +/- 0.29\nw2     576967\t  588902    944      19.64 +/- 0.23\n\nThe magnitudes in the table are not corrected for the Galactic extinction due to the\nsignificant reddening of E(B-V) = 0.23 in the direction of the burst (Schlegel et al. 1998).\n\nIn XRT, no source was found at the location of ZTF20aamvmzj, down to a 3-sigma upper limit of\n3.1e-3 count s^-1 in 3 ks of exposure. Assuming a power-law spectrum with NH=3x10^20 cm^-2, and\nphoton index (Gamma)=1.7, this equates to a upper limit of F < 1.2x10^-13 erg cm^-2 s^-1 on\nthe 0.3-10 keV observed flux.\n\nThis circular is an official product of the Swift team.",
  "circularId": 27153,
  "createdOn": 1582206637000,
  "email": "sro@mssl.ucl.ac.uk",
  "subject": "LIGO/Virgo S200213t: Swift UVOT and XRT observations of ZTF20aamvmzj (AT2020cja)",
  "submitter": "Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>",
  "eventId": "LIGO/Virgo S200213t"
}