COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses

XVI. Time delays for the quadruply imaged quasar DES J0408−5354 with high-cadence photometric monitoring^⋆

¹ Institute of Physics, Laboratory of Astrophysics, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
e-mail: vivien.bonvin@epfl.ch
² Fermi National Accelerator Laboratory, PO Box 500, Batavia, IL 60510, USA
³ Department of Physics, University of California, Davis, CA 95616, USA
⁴ Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA
⁵ Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 452 Lomita Mall, Stanford, CA 94035, USA
⁶ Max Planck Institute for Astrophysics, Karl-Schwarzschild-Strasse 1, 85740 Garching, Germany
⁷ Physik-Department, Technische Universität München, James-Franck-Straße 1, 85748 Garching, Germany
⁸ Institute of Astronomy and Astrophysics, Academia Sinica, PO Box 23-141, 10617 Taipei, Taiwan, PR China
⁹ Department of Physics and Astronomy, University of California, Los Angeles, CA 90095, USA
¹⁰ Departamento de Ciencias Físicas, Universidad Andres Bello Fernandez Concha 700, Las Condes, Santiago, Chile
¹¹ Millennium Institute of Astrophysics, Santiago, Chile
¹² Instituto de Física y Astronomía, Universidad de Valparaíso, Avda. Gran Bretaña 1111, Playa Ancha, 2360102 Valparaíso, Chile
¹³ Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany
¹⁴ European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen, Germany
¹⁵ Centro de Astroingeniería, Facultad de Física, Pontificia Universidad Católica deChile, Av. Vicuña Mackenna 4860, Macul 7820436, Santiago, Chile
¹⁶ Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
¹⁷ Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena, Chile
¹⁸ Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
¹⁹ Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
²⁰ LSST, 933 North Cherry Avenue, Tucson, AZ 85721, USA
²¹ CNRS, UMR 7095, Institut d’Astrophysique de Paris, 75014 Paris, France
²² Department of Physics & Astronomy, University College London, Gower Street, London, WC1E 6BT, UK
²³ Sorbonne Universités, UPMC Univ. Paris 06, UMR 7095, Institut d’Astrophysique de Paris, 75014 Paris, France
²⁴ Kavli Institute for Particle Astrophysics & Cosmology, PO Box 2450, Stanford University, Stanford, CA 94305, USA
²⁵ SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
²⁶ Laboratório Interinstitucional de e-Astronomia – LIneA, Rua Gal. José Cristino 77, Rio de Janeiro, RJ – 20921-400, Brazil
²⁷ Observatório Nacional, Rua Gal. José Cristino 77, Rio de Janeiro, RJ – 20921-400, Brazil
²⁸ Department of Astronomy, University of Illinois, 1002 W. Green Street, Urbana, IL 61801, USA
²⁹ National Center for Supercomputing Applications, 1205 West Clark St., Urbana, IL 61801, USA
³⁰ Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra (Barcelona), Spain
³¹ Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
³² George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA
³³ Department of Physics, IIT Hyderabad, Kandi, Telangana 502285, India
³⁴ Institut de Ciències de l’Espai, IEEC-CSIC, Campus UAB, Carrer de Can Magrans, s/n, 08193 Bellaterra, Barcelona, Spain
³⁵ Instituto de Fisica Teorica UAM/CSIC, Universidad Autonoma de Madrid, 28049 Madrid, Spain
³⁶ Department of Astronomy, University of California, Berkeley, 501 Campbell Hall, Berkeley, CA 94720, USA
³⁷ Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
³⁸ Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210, USA
³⁹ Department of Physics, The Ohio State University, Columbus, OH 43210, USA
⁴⁰ Astronomy Department, University of Washington, Box 351580, Seattle, WA 98195, USA
⁴¹ Australian Astronomical Observatory, North Ryde, NSW 2113, Australia
⁴² Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439, USA
⁴³ Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP 66318, São Paulo, SP, 05314-970, Brazil
⁴⁴ Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
⁴⁵ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA
⁴⁶ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), 28040 Madrid, Spain
⁴⁷ Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
⁴⁸ School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ, UK
⁴⁹ Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, 13083-859 Campinas, SP, Brazil
⁵⁰ Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA

Received: 28 June 2017
Accepted: 5 October 2017

Abstract

We present time-delay measurements for the new quadruple imaged quasar DES J0408−5354, the first quadruple imaged quasar found in the Dark Energy Survey (DES). Our result is made possible by implementing a new observational strategy using almost daily observations with the MPIA 2.2 m telescope at La Silla observatory and deep exposures reaching a signal-to-noise ratio of about 1000 per quasar image. This data qualityallows us to catch small photometric variations (a few mmag rms) of the quasar, acting on temporal scales much shorter than microlensing, and hence making the time delay measurement very robust against microlensing. In only seven months we very accurately measured one of the time delays in DES J0408−5354: Δt(AB) = −112.1 ± 2.1 days (1.8%) using only the MPIA 2.2 m data. In combination with data taken with the 1.2 m Euler Swiss telescope, we also measured two delays involving the D component of the system Δt(AD) = −155.5 ± 12.8 days (8.2%) and Δt(BD) = −42.4 ± 17.6 days (41%), where all the error bars include systematics. Turning these time delays into cosmological constraints will require deep Hubble Space Telescope (HST) imaging or ground-based adaptive optics (AO), and information on the velocity field of the lensing galaxy.