The Astrophysical Journal, 858:18 (16pp), 2018 May 1 https://doi.org/10.3847/1538-4357/aabad9 © 2018. The American Astronomical Society. All rights reserved. An Empirical Study of Contamination in Deep, Rapid, and Wide-field Optical Follow-up of Gravitational Wave Events P. S. Cowperthwaite1,12 , E. Berger1 , A. Rest2,3, R. Chornock4, D. M. Scolnic5, P. K. G. Williams1 , W. Fong6 , M. R. Drout7,13, R. J. Foley8, R. Margutti6 , R. Lunnan9 , B. D. Metzger10 , and E. Quataert11 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA;
[email protected] 2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA 3 Department of Physics and Astronomy, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA 4 Astrophysical Institute, Department of Physics and Astronomy, 251B Clippinger Lab, Ohio University, Athens, OH 45701, USA 5 Kavli Institute for Cosmological Physics, The University of Chicago, Chicago, IL 60637, USA 6 CIERA and Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA 7 The Observatories of the Carnegie Institution for Science, 813 Santa Barbara St., Pasadena, CA 91101, USA 8 Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA 9 The Oskar Klein Centre & Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm, Sweden 10 Department of Physics and Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA 11 Department of Astronomy & Theoretical Astrophysics Center, University of California, Berkeley, CA 94720-3411, USA Received 2017 October 5; revised 2018 March 27; accepted 2018 March 27; published 2018 April 27 Abstract We present an empirical study of contamination in wide-field optical follow-up searches of gravitational wave sources from Advanced LIGO/Virgo using dedicated observations with the Dark Energy Camera.