{
  "bibcode": "2020GCN.27051....1K",
  "body": "Mansi M. Kasliwal (Caltech), Daniel Perley (LJMU), Harsh Kumar (IITB), Igor\nAndreoni (Caltech), Kishalay De (Caltech), Viraj Karambelkar (Caltech),\nVarun Bhalerao (IITB), Erik Kool (OKC), Jesper Sollerman (OKC), Ana\nCarracedo (OKC), Michael Coughlin (U Minn), Eric Bellm (UW), Leo Singer\n(NASA GSFC), Shreya Anand (Caltech), Tomas Ahmuda (UMd)\n\non behalf of the ZTF and GROWTH collaborations\n\nWe observed the localization region of the gravitational wave trigger\nS200213t (LVC, GCN #27042) with the Palomar 48-inch telescope equipped with\nthe 47 square degree Zwicky Transient Facility camera (ZTF, Bellm et al.\n2019, Graham et al. 2019).\n\nThe tiling was optimally determined and triggered using the GROWTH Target\nof Opportunity marshal (Coughlin et al. 2019a, Kasliwal et al. 2019b). We\nstarted obtaining target-of-opportunity observations in the g-band and\nr-band beginning at 2020-02-13 04:36 UT, targeting ~77% of the enclosed\nprobability based on the bayestar skymap (LVC, GCN #27042). Each exposure\nwas 120s with a median depth of ~20.7 mag.\n\nThe images were processed in real-time through the ZTF reduction and image\nsubtraction pipelines at IPAC to search for potential counterparts (Masci\net al. 2019). Alert filtering and follow-up coordination was undertaken by\nthe GROWTH Marshal system (Kasliwal et al. 2019). The ZTF alert stream was\nalso queried using the Kowalski infrastructure (Duev et al., 2019). We\nrequired at least 2 detections separated by at least 30 minutes to select\nagainst moving objects. Furthermore, we cross-matched our candidates with\nthe Minor Planet Center to flag known asteroids. Candidates that passed our\nselection are:\n\n+--------------+----------+-------------+--------------+--------+------+----------+-------+\n|     Name     | IAU Name |      RA     |     Dec      | filter | mag  |\nMJD    | Notes |\n+--------------+----------+-------------+--------------+--------+------+----------+-------+\n| ZTF20aamvqxl |    AT2020ciy    | 01:56:57.10 | +53:40:07.97 |   r    |\n20.1 | 58892.22 | Offset from Host Galaxy |\n| ZTF20aamvnth |    AT2020cjb    | 01:13:21.05 | +49:38:43.94 |   g    |\n20.4 | 58892.20 | Offset from Host Galaxy      |\n| ZTF20aamvoxx |    AT2020cjg    | 02:37:35.78 | +26:55:14.22 |   g    |\n20.0 | 58892.21 | SDSS phot-z 0.110 +/- 0.008      |\n| ZTF20aamvtip |    AT2020cje    | 02:32:19.81 | +27:48:36.34 |   r    |\n20.6 | 58892.24 | SDSS phot-z 0.22 +/- 0.06 |\n| ZTF20aamvnat |    AT2020ciz    | 01:48:57.49 | +56:21:16.49 |   g    |\n19.0 | 58892.21 | Faint Red Counterpart in PS1      |\n| ZTF20aamvmzj |    AT2020cja    | 01:48:45.41 | +51:25:49.73 |   g    |\n20.6 | 58892.20 | Hostless       |\n| ZTF20aamvoeh |    AT2020cjc    | 02:14:00.48 | +38:56:10.74 |   g    |\n20.6 | 58892.21 | Nuclear/Stellar?       |\n| ZTF20aamvodd |    AT2020cjf    | 02:29:55.77 | +50:19:09.94 |   g    |\n19.7 | 58892.20 | Faint Red Counterpart in PS1      |\n+--------------+----------+-------------+--------------+--------+------+----------+-------+\n\nWe encourage follow-up to classify the candidates. We caution that these\ncandidates are low Galactic latitude and the magnitudes reported are not\nextinction corrected.\n\nZTF and GROWTH are worldwide collaborations comprising Caltech, USA; IPAC,\nUSA, WIS, Israel; OKC, Sweden; JSI/UMd, USA; U Washington, USA; DESY,\nGermany; MOST, Taiwan; UW Milwaukee, USA; LANL USA; Tokyo Tech, Japan;\nIITB, India; IIA, India; LJMU, UK; TTU, USA; SDSU, USA and USyd, Australia.\nZTF acknowledges the generous support of the NSF under AST MSIP Grant No\n1440341. GROWTH acknowledges generous support of the NSF under PIRE Grant\nNo 1545949. Alert distribution service provided by DIRAC@UW (Patterson et\nal. 2019). Alert filtering and follow-up coordination is being undertaken\nby the GROWTH marshal system (Kasliwal et al. 2019). Alert database\nsearches are done with using the Kowalski infrastructure (Duev et al.,\n2019) and with AMPEL (Nordin et al. 2019).",
  "circularId": 27051,
  "createdOn": 1581579179000,
  "email": "mansikasliwal@gmail.com",
  "subject": "LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility",
  "submitter": "Mansi M. Kasliwal at Caltech/Carnegie  <mansikasliwal@gmail.com>",
  "eventId": "LIGO/Virgo S200213t"
}