Kilpatrick, Charles DCoulter, David A.Arcavi, IBrink, T. G.Dimitriadis, G.Filippenko, Alexei VFoley, Ryan JHowell, D. AndrewJones, David OKasen, D.Tucker, Brad2024-03-212024-03-211538-4357http://hdl.handle.net/1885/316209We present optical follow-up imaging obtained with the Katzman Automatic Imaging Telescope, Las Cumbres Observatory Global Telescope Network, Nickel Telescope, Swope Telescope, and Thacher Telescope of the LIGO/Virgo gravitational wave (GW) signal from the neutron star-black hole (NSBH) merger GW190814. We searched the GW190814 localization region (19 deg(2) for the 90th percentile best localization), covering a total of 51 deg(2) and 94.6% of the two-dimensional localization region. Analyzing the properties of 189 transients that we consider as candidate counterparts to the NSBH merger, including their localizations, discovery times from merger, optical spectra, likely host galaxy redshifts, and photometric evolution, we conclude that none of these objects are likely to be associated with GW190814. Based on this finding, we consider the likely optical properties of an electromagnetic counterpart to GW190814, including possible kilonovae and short gamma-ray burst afterglows. Using the joint limits from our follow-up imaging, we conclude that a counterpart with an r-band decline rate of 0.68 mag day(-1), similar to the kilonova AT 2017gfo, could peak at an absolute magnitude of at most -17.8 mag (50% confidence). Our data are not constraining for "red" kilonovae and rule out "blue" kilonovae with M > 0.5 M (circle dot) (30% confidence). We strongly rule out all known types of short gamma-ray burst afterglows with viewing angles <17 degrees assuming an initial jet opening angle of similar to 5.degrees 2 and explosion energies and circumburst densities similar to afterglows explored in the literature. Finally, we explore the possibility that GW190814 merged in the disk of an active galactic nucleus, of which we find four in the localization region, but we do not find any candidate counterparts among these sources.Much of this work was performed during the “Astrophysics in the LIGO/Virgo Era” meeting at the Aspen Center for Physics during Summer 2019, with C.D.K., D.A.C., I.A., D.O. J., C.R.-B., E.R.-R., A.R., and M.R.S. all participating. The Aspen Center for Physics is supported by National Science Foundation (NSF) grant PHY-1607611. The UCSC team is supported in part by NASA grant NNG17PX03C, NSF grant AST-1815935, the Gordon & Betty Moore Foundation, the Heising-Simons Foundation, and by fellowships from the David and Lucile Packard Foundation to R.J.F. D.A.C. acknowledges support from the NSF Graduate Research Fellowship under grant DGE1339067. A.V.F.ʼs group at UC Berkeley is grateful for financial assistance from the Miller Institute for Basic Research in Science (in which A.V.F. is a Miller Senior Fellow), the Christopher R. Redlich Fund, Sunil Nagaraj, Landon Noll (K.C.P. is a Nagaraj-Noll Graduate Fellow), Steven Nelson (S.S.V. is a Steven Nelson Graduate Fellow), and many other individual donors. D.E.H. was supported by NSF grants PHY-1708081 and PHY-2011997, and the Kavli Institute for Cosmological Physics at the University of Chicago through an endowment from the Kavli Foundation. Time-domain research by D.J.S. is supported by NSF grants AST-1821987, 1813466, and 1908972, and by the HeisingSimons Foundation under grant #2020-1864. F.O.E. acknowledges support from FONDECYT grant 1201223. I. A. is a CIFAR Azrieli Global Scholar in the Gravity and the Extreme Universe Program and acknowledges support from that program, from the European Research Council (ERC) under the European Unionʼs Horizon 2020 research and innovation program (grant agreement 852097), from the Israel Science Foundation (grant 2752/19), from the United States—Israel Binational Science Foundation (BSF), and from the Israeli Council for Higher Education Alon Fellowship. J.B. is supported by NSF grants AST-1313484 and AST-1911225, as well as by NASA grant 80NSSC19kf1639. J.C. acknowledges support from the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav) project CE170100004. J.G.B. is supported by MINECO project PGC2018-094773-B-C32. L.S. S. acknowledges the financial support from FAPESP through grant #2020/03301-5. M.M. is supported by CONICET, CNPq, and FAPERJ. M.R.S. is supported by the NSF Graduate Research Fellowship Program under grant 184240. The U.M. team is supported by NSF grant AST-1910719 and fellowships from the Alfred P. Sloan Foundation and the Cottrell Scholar Award to M.S.-S. N.H. acknowledges support for this work by Israel Science Foundation grant 541/17. R.R.d.C. acknowledges financial support from FAPESP through grant #2014/11156-4. R.R.M. acknowledges partial support from project BASAL AFB-170002 as well as FONDECYT project 1170364. S.B.R. acknowledges support from Conselho Nacional de Desenvolvimento Científico e Tecnológico—CNPq. T.D. is supported by ARC grant FL180100168. T.L.P. acknowledges financial support from CAPES. This work includes data obtained with the Swope Telescope at Las Campanas Observatory, Chile, as part of the Swope Time Domain Key Project (PI Piro; Co-Is Burns, Cowperthwaite, Dimitriadis, Drout, Foley, French, Holoien, Hsiao, Kilpatrick, Madore, Phillips, and Rojas-Bravo). This work makes use of observations from the LCO Network. The LCO Group is supported by NSF grant AST-1911151.application/pdfen-AU© 2021. The American Astronomical SocietyGravitational wavesNeutron starsBlack holes202110.3847/1538-4357/ac23c62022-11-13