SDSS-IV eBOSS emission-line galaxy pilot survey^⋆

¹ Instituto de Fisica Teorica UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
e-mail: j.comparat@csic.es
² Departamento de Fisica Teorica, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
³ Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
⁴ Department of Physics and Astronomy, University College London, Gower Street, London WC1E6 BT, UK
⁵ CEA, Centre de Saclay, IRFU/SPP, 91191 Gif-sur-Yvette, France
⁶ Aix Marseille Université, CNRS, LAM (Laboratoire d’Astrophysique de Marseille) UMR 7326, 13388 Marseille, France
⁷ Department of Physics & Electronics, Rhodes University, 6140 Grahamstown, South Africa
⁸ Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth, PO1 3FX, UK
⁹ Department of Physics & Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA
¹⁰ Instituto de Astrofísica de Andalucía (CSIC), Glorieta de la Astronomía, 18080 Granada, Spain
¹¹ Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
¹² Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 100012 Beijing, PR China
¹³ Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112, USA
¹⁴ Apache Point Observatory and New Mexico State University, PO Box 59, Sunspot, NM, 88349-0059, USA
¹⁵ Sternberg Astronomical Institute, Moscow State University, Moscow  
¹⁶ CPPM, Aix-Marseille Université, CNRS/IN2P3, 13388 Marseille, France
¹⁷ Department of Physics and Astronomy and PITT PACC, University of Pittsburgh, Pittsburgh, PA 15260, USA
¹⁸ Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA
¹⁹ Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
²⁰ Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, Casilla 603, La Serena, Chile
²¹ Fermi National Accelerator Laboratory, PO Box 500, Batavia, IL 60510, USA
²² Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
²³ Kavli Institute for Cosmology, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK
²⁴ CNRS, UMR 7095, Institut d’Astrophysique de Paris, 75014 Paris, France
²⁵ Sorbonne Universités, UPMC Univ Paris 06, UMR 7095, Institut d’Astrophysique de Paris, 75014 Paris, France
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 Ciències de l’Espai, IEEC-CSIC, Campus UAB, Carrer de Can Magrans, s/n, 08193 Bellaterra, Barcelona, Spain
³¹ Institut de Física d’Altes Energies, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
³² Kavli Institute for Particle Astrophysics & Cosmology, PO Box 2450, Stanford University, Stanford, CA 94305, USA
³³ Excellence Cluster Universe, Boltzmannstr. 2, 85748 Garching, Germany
³⁴ Faculty of Physics, Ludwig-Maximilians University, Scheinerstr. 1, 81679 Munich, Germany
³⁵ Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA
³⁶ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA
³⁷ Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637, USA
³⁸ Department of Physics, University of Michigan, Ann Arbor, MI 48109, USA
³⁹ Max Planck Institute for Extraterrestrial Physics, Giessenbachstrasse, 85748 Garching, Germany
⁴⁰ Universitäts-Sternwarte, Fakultät für Physik, Ludwig-Maximilians Universität München, Scheinerstr. 1, 81679 München, Germany
⁴¹ Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210, USA
⁴² Department of Physics, The Ohio State University, Columbus, OH 43210, USA
⁴³ Australian Astronomical Observatory, North Ryde, NSW 2113, Australia
⁴⁴ Departamento de Física Matemática, Instituto de Física, Universidade de São Paulo, CP66318, CEP 05314-970, São Paulo, SP, Brazil
⁴⁵ 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
⁴⁶ Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
⁴⁷ SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
⁴⁸ Department of Physics and Astronomy, Pevensey Building, University of Sussex, Brighton, BN1 9QH, UK
⁴⁹ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
⁵⁰ Department of Physics, University of Illinois, 1110 W. Green St., Urbana, IL 61801, USA

Received: 16 September 2015
Accepted: 13 June 2016

Abstract

The Sloan Digital Sky Survey IV extended Baryonic Oscillation Spectroscopic Survey (SDSS-IV/eBOSS) will observe 195 000 emission-line galaxies (ELGs) to measure the baryonic acoustic oscillation (BAO) standard ruler at redshift 0.9. To test different ELG selection algorithms, 9000 spectra were observed with the SDSS spectrograph as a pilot survey based on data from several imaging surveys. First, using visual inspection and redshift quality flags, we show that the automated spectroscopic redshifts assigned by the pipeline meet the quality requirements for a reliable BAO measurement. We also show the correlations between sky emission, signal-to-noise ratio in the emission lines, and redshift error. Then we provide a detailed description of each target selection algorithm we tested and compare them with the requirements of the eBOSS experiment. As a result, we provide reliable redshift distributions for the different target selection schemes we tested. Finally, we determine an target selection algorithms that is best suited to be applied on DECam photometry because they fulfill the eBOSS survey efficiency requirements.