{
  "bibcode": "2020GCN.27073....1M",
  "body": "Curtis McCully (LCO), Daichi Hiramatsu (LCO/UCSB), Jamison Burke\n(LCO/UCSB), Jennifer Andrews (UA), Craig Peligrino (LCO/UCSB), D. Andrew\nHowell (LCO/UCSB), Iair Arcavi (Tel Aviv University), Reinaldo de Carvalho:\n(Unicid/Unicsul), Francisco Fo��rster (Universidad de Chile), Ryan Foley\n(UCSC), David Coulter (UCSC), Charles Kilpatrick (UCSC), David Sand (UA),\nStefano Valenti (UC Davis), Marcelle Soares-Santos (Brandeis), Sandro\nRembold (UFSM), Armin Rest (STSci), Daniel Kasen (UC Berkeley), Brian\nMetzger (Columbia), Anthony Piro (Carnegie Obs.), Eliot Quataert (UC\nBerkeley), Enrico Ramirez-Ruiz (UCSC), J. Craig Wheeler (UT Austin), Franz\nBauer (Pontificia Universidad Catolica de Chile), Joshua Bloom (UC\nBerkeley), Thomas Brink (UC Berkeley), Jeff Cooke (Swinburne University of\nTechnology), Alejandro Clocchiatti (Pontificia Universidad Catolica de\nChile), Alexei V. Filippenko (UC Berkeley), Wendy Freedman (University of\nChicago), Peter Garnavich (Notre Dame), Jorge Ernesto Horvath (Universidade\nde Sao Paulo), Saurabh Jha (Rutgers), Robert Kirshner (Gordon and Betty\nMoore Foundation), Kevin Krisciunas (Texas A&M), Huan Lin (FNAL), Barry\nMadore (Carnegie Obs.),  Martin Makler (Centro Brasileiro de Pesquisas\nFi��sicas), Gautham Narayan (UIUC), Xavier Prochaska (UCSC), Adam Riess\n(STSci), Riccardo Sturani (UFRN), Nicholas Suntzeff (Texas A&M), Masaomi\nTanaka (Tohoku University), Douglas Tucker (FNAL), Jozsef Vinko (Konkoly\nObservatory), Lifan Wang (Texas A&M), Carlos Contreras (STSci), Chris\nD'Andrea (UPenn), Georgios Dimitriadis (UCSC), David Jones (UCSC), Michael\nLundquist (UA), Felipe Olivares (INCT/UDA), Antonella Palmese (FNAL),\nYen-Chen Pan: (NAOJ), Daniel Scolnic (University of Chicago), WeiKang Zheng\n(UC Berkeley), Antonio Bernardo (Universidade de Sao Paulo), K. Azalee\nBostroem (UC Davis), Ariadna Murguia Berthier (UCSC), O��smar Rodri��guez\n(Universidad Nacional Andres Bello), Ce��sar Rojas-Bravo (UCSC), Matthew\nSiebert (UCSC), and Iruata�� Souza (Centro Brasileiro de Pesquisas)\n\nFollowing the detection of S200114f (LIGO/Virgo Collaboration, GCN 26734),\nthe Zwicky Transient Facility reported a list of possible optical\ncounterparts (Andreoni et al., GCN 26741). We triggered our follow-up\nprogram on the Gemini Telescopes (GS-2019B-Q-115; PI McCully) to classify\nthe candidates. We obtained optical spectra of AT 2020vu, 2020vw, 2020vy,\nand 2020vz using the GMOS instrument on Gemini South. These targets were\nchosen because they were visible from Chile as Gemini North was closed due\nto bad weather. They were observed consecutively starting at 2020-01-16\n01:55 UTC, less than 48 hours after merger detection.\n\nThese targets were triggered using the TOM Toolkit (Street et al., 2018,\narXiv 1806.09557) through Gemini's programmatic interface.\n\nThe spectra were reduced using a combination of Gemini IRAF tasks and\ncustom Python routines (https://github.com/cmccully/lcogtgemini). We used\nboth SNID (Blondin & Tonry 2007, ApJ, 666, 1024) and Superfit (Howell et\nal. 2005, ApJ, 634, 1190) to classify these transients. Throughout, we\nadopt a Hubble constant of H_0 =  71 km/s/Mpc and a flat cosmological model\nwith a dark energy density of 0.7. The classifications and spectra have\nbeen uploaded to the Transient Name Server (TNS).\n\n\n\nFor AT 2020vz, we find a best fit using Superfit of SN 2005cl, a Type IIn\nSN, at +15 days with redshift z = 0.25. This corresponds to an absolute\nmagnitude of -19.4, consistent with this type of supernova.\nhttps://wis-tns.weizmann.ac.il/object/2020vz\n\nAT 2020vy was best fit by SN 1999aa before peak brightness at z = 0.24. At\nthis redshift, the source has an absolute magnitude of -19.2, consistent\nwith a SN Ia. https://wis-tns.weizmann.ac.il/object/2020vy\n\n\n\nAT 2020vu is consistent with a quasar. The spectrum exhibits a strong,\nbroad feature near 5360 A. Assuming this is Mg II, the quasar is at  z =\n0.91. At this redshift, there are also spectral features consistent with\nthe hydrogen Balmer series and [O III].\nhttps://wis-tns.weizmann.ac.il/object/2020vu\n\nFor AT 2020vw, the best fit is with a normal SN Ia near peak brightness at\nz = 0.23, consistent with the absolute magnitude estimate of -19.0 at that\ndistance. https://wis-tns.weizmann.ac.il/object/2020vw\n\nTherefore, we conclude that all of these transients (AT 2020vy, 2020vz,\n2020vu, and 2020vw) are not associated with the GW alert S200114f.\n\n\n\nWe thank the Gemini team for their rapid response and assistance in\nobtaining these observations.",
  "circularId": 27073,
  "createdOn": 1581732940000,
  "email": "cmccully@lco.global",
  "subject": "LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz",
  "submitter": "Curtis McCully at Las Cumbres Observatory  <cmccully@lco.global>",
  "eventId": "LIGO/Virgo S200114f"
}