{
  "bibcode": "2020GCN.27068....1R",
  "body": "*\n\nSimeon Reusch (DESY), Robert Stein (DESY), Daniel Perley (LJMU),\nShreya Anand (Caltech)\n\n\nOn behalf of the Zwicky Transient Facility (ZTF) and Global Relay of\nObservatories Watching Transients Happen (GROWTH) collaborations:��\n\n\nWe observed the localization region of LIGO/Virgo S200213t with the\nPalomar 48-inch telescope, equipped with the 47 square degree ZTF camera\n(Bellm et al. 2019, Graham et al. 2019). We started observations in the\ng- and r-band beginning at 2020-02-13T04:34:34.500 UTC, approximately\n0.4 hours after event time. We covered 78.5% of the enclosed probability\nbased on the map in 1999.2 sq deg. This estimate accounts for chip gaps.\nEach exposure was 30s with a typical depth of 20.5 mag.��\n\n��\n\nThe images were processed in real-time through the ZTF reduction and\nimage subtraction pipelines at IPAC to search for potential counterparts\n(Masci et al. 2019). AMPEL (Nordin et al. 2019) was used to search the\nalerts database for candidates. We reject stellar sources (Tachibana and\nMiller 2018) and moving objects, apply machine learning algorithms\n(Mahabal et al. 2019), and remove candidates with history of variability\nprior to the merger time. We are left with the following additional\nhigh-significance transient candidate by our pipeline, lying within the\n95.0% localization of the skymap.��\n\n\n+---------------------------------------------------------------------------------+\n| ZTF Name �� �� | IAU Name   | RA (deg)�� �� | DEC (deg)   | Filter | Mag �� | MagErr |\n+---------------------------------------------------------------------------------+����\n| ZTF20aanakcd | AT 2020cmr | 008.1570525 | +41.3157344 | r�� �� �� | 20.59 | 0.13   |\n+---------------------------------------------------------------------------------+\n\n\nZTF20aanakcd (AT 2020cmr) has a host with an estimated photometric\nredshift of 0.05 +/- 0.03, derived using ANNz2 (Sadeh et. al., 2015)\nbased on photometry from the Pan-STARRS survey (Chambers et. al., 2019).\nThis redshift is compatible with the reported GW distance. We caution\nthat this value is only a preliminary estimate.\n\n\nWe encourage photometric and spectroscopic follow-up to classify this\nadditional candidate.\n\n\nZTF and GROWTH are worldwide collaborations comprising Caltech, USA;\nIPAC, USA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA;\nDESY, Germany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech,\nJapan; IITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd,\nAustralia.\n\nZTF acknowledges the generous support of the NSF under AST MSIP Grant No\n1440341.��\n\nGROWTH acknowledges generous support of the NSF under PIRE Grant No 1545949.\n\nAlert distribution service provided by DIRAC@UW (Patterson et al. 2019).\n\nAlert database searches are done by AMPEL (Nordin et al. 2019).\n\n*\n\n[GCN OPS NOTE(04feb20): Per author's request, in the author list,\nPerley's affiliation was corrected from \"Caltech\" to \"LJMU\".]",
  "circularId": 27068,
  "createdOn": 1581688824000,
  "email": "simeon.reusch@desy.de",
  "subject": "LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility",
  "submitter": "Simeon Reusch at DESY  <simeon.reusch@desy.de>",
  "eventId": "LIGO/Virgo S200213t"
}