A Study of Quasar Selection in the Dark Energy Survey Supernova fields

Abstract

We present a study of quasar selection using the DES supernova fields. We used a quasar catalog from an overlapping portion of the SDSS Stripe 82 region to quantify the completeness and efficiency of selection methods involving color, probabilistic modeling, variability, and combinations of color/probabilistic modeling with variability. We only considered objects that appear as point sources in the DES images. We examine color selection methods based on the WISE mid-IR W1-W2 color, a mixture of WISE and DES colors (g-i and i-W1) and a mixture of VHS and DES colors (g-i and i-K). For probabilistic quasar selection, we used XDQSOz, an algorithm that employs an empirical multi-wavelength flux model of quasars to assign quasar probabilities. Our variability selection uses the multi-band chi2-probability that sources are constant in the DES Year 1 griz-band light curves. The completeness and efficiency are calculated relative to an underlying sample of point sources that are detected in the required selection bands and pass our data quality and photometric error cuts. We conduct our analyses at two magnitude limits, i<19.8 mag and i<22 mag. For sources with W1 and W2 detections, the W1-W2 color or XDQSOz method combined with variability gives the highest completenesses of >85% for both i-band magnitude limits and efficiencies of >80% to the bright limit and >60% to the faint limit; however, the giW1 and giW1+variability methods give the highest quasar surface densities. The XDQSOz method and combinations of W1W2/giW1/XDQSOz with variability are among the better selection methods when both high completeness and high efficiency are desired. We also present the OzDES Quasar Catalog of 1,263 spectroscopically-confirmed quasars taken by the OzDES survey. The catalog includes quasars with redshifts up to z~4 and brighter than i=22 mag, although the catalog is not complete up this magnitude limit.

arXiv comment16 pages, 12 figures, 3 tables; Submitted to ApJ. The OzDES Quasar Catalog can be downloaded at http://bit.ly/2fWsK9t . For a video summary of the paper, please see https://www.youtube.com/watch?v=JeQNdUATze0

References in corpus (64)

• Astropy: A Community Python Package for Astronomy
• The Sloan Digital Sky Survey: Technical Summary
• Seven-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Seventh Data Release of the Sloan Digital Sky Survey
• The Baryon Oscillation Spectroscopic Survey of SDSS-III
• The Eighth Data Release of the Sloan Digital Sky Survey: First Data from SDSS-III
• The Dark Energy Camera
• Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Quasar Sample
• Measuring and Modelling the Redshift Evolution of Clustering: the Hubble Deep Field North
• The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
• Baryon Acoustic Oscillations in the Lyα forest of BOSS DR11 quasars
• Preliminary Results from NEOWISE: An Enhancement to the Wide-field Infrared Survey Explorer for Solar System Science
• The SDSS Quasar Survey: Quasar Luminosity Function from Data Release Three
• Mid-Infrared Selection of AGN with the Wide-Field Infrared Survey Explorer. I. Characterizing WISE-Selected AGN in COSMOS
• Are the Variations in Quasar Optical Flux Driven by Thermal Fluctuations?
• Initial Performance of the NEOWISE Reactivation Mission
• CFHTLenS: The Canada-France-Hawaii Telescope Lensing Survey
• Modeling the Time Variability of SDSS Stripe 82 Quasars as a Damped Random Walk
• Obscured and unobscured active galactic nuclei in the Spitzer Space Telescope First Look Survey
• The 2dF QSO Redshift Survey - XII. The spectroscopic catalogue and luminosity function
• The Chandra Deep Field-South Survey: 4 Ms Source Catalogs
• Quasar-Lyman $\alpha$ Forest Cross-Correlation from BOSS DR11 : Baryon Acoustic Oscillations
• The 6dF Galaxy Survey: Samples, Observational Techniques and the First Data Release
• Eight Ultra-faint Galaxy Candidates Discovered in Year Two of the Dark Energy Survey
• The Ensemble Photometric Variability of ~25000 Quasars in the Sloan Digital Sky Survey
• Bayesian Galaxy Shape Measurement for Weak Lensing Surveys - III. Application to the Canada-France-Hawaii Telescope Lensing Survey
• Mid-Infrared Selection of Active Galactic Nuclei with the Wide-Field Infrared Survey Explorer. II. Properties of WISE-Selected Active Galactic Nuclei in the NDWFS Boötes Field
• The First Hundred Brown Dwarfs Discovered by the Wide-field Infrared Survey Explorer (WISE)
• The VIMOS VLT Deep Survey - First epoch VVDS-Deep survey: 11564 spectra with 17.5<=IAB<=24, and the redshift distribution over 0< z <=5
• CFHTLenS: The Canada-France-Hawaii Telescope Lensing Survey - Imaging Data and Catalogue Products
• The Discovery of Y Dwarfs Using Data from the Wide-field Infrared Survey Explorer (WISE)
• Quantifying Quasar Variability As Part of a General Approach To Classifying Continuously Varying Sources
• Efficient Photometric Selection of Quasars from the Sloan Digital Sky Survey: II. ~1,000,000 Quasars from Data Release Six
• The Anglo-Australian Observatory's 2dF Facility
• Low Resolution Spectral Templates For AGNs and Galaxies From 0.03 -- 30 microns
• The SDSS-III Baryon Oscillation Spectroscopic Survey: Quasar Target Selection for Data Release Nine
• The Blanco Cosmology Survey: Data Acquisition, Processing, Calibration, Quality Diagnostics and Data Release
• Think Outside the Color Box: Probabilistic Target Selection and the SDSS-XDQSO Quasar Targeting Catalog
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Quasar Target Selection
• Supernova Simulations and Strategies For the Dark Energy Survey
• Light and Motion in SDSS Stripe 82: The Catalogues
• Extreme deconvolution: Inferring complete distribution functions from noisy, heterogeneous and incomplete observations
• Selecting Quasars by their Intrinsic Variability
• Optimal Time-Series Selection of Quasars
• Photometric redshifts and quasar probabilities from a single, data-driven generative model
• MARZ: Manual and Automatic Redshifting Software
• SDSS quasars in the WISE preliminary data release and quasar candidate selection with optical/infrared colors
• OzDES multi-fibre spectroscopy for the Dark Energy Survey: first-year operation and results
• Variability selected high-redshift quasars on SDSS Stripe 82
• An Empirical Calibration of the Completeness of the SDSS Quasar Survey
• The KX method for producing K-band flux-limited samples of quasars
• The Dark Energy Survey Data Processing and Calibration System
• DES J0454-4448: Discovery of the First Luminous z > 6 Quasar from the Dark Energy Survey
• Mass Functions of Supermassive Black Holes Across Cosmic Time
• Quasar Probabilities and Redshifts from WISE mid-IR through GALEX UV Photometry
• Simulations of the OzDES AGN Reverberation Mapping Project
• The large area KX quasar catalogue: I. Analysis of the photometric redshift selection and the complete quasar catalogue
• A Simple Likelihood Method for Quasar Target Selection
• Long Term Variability of SDSS Quasars
• Combining Dark Energy Survey Science Verification Data with Near Infrared Data from the ESO VISTA Hemisphere Survey
• A UV to Mid-IR Study of AGN Selection
• The 2QDES Pilot : The luminosity and redshift dependence of quasar clustering

Cited by in corpus (21)

• OzDES multifibre spectroscopy for the Dark Energy Survey: Three year results and first data release
• Quasar Accretion Disk Sizes From Continuum Reverberation Mapping From the Dark Energy Survey
• HELP: A catalogue of 170 million objects, selected at 0.36-4.5 $\mu$m, from 1270 deg.${}^2$ of prime extragalactic fields
• Quasar Accretion Disk Sizes from Continuum Reverberation Mapping in the DES Standard Star Fields
• CIV Black Hole Mass Measurements with the Australian Dark Energy Survey (OzDES)
• Brown dwarf census with the Dark Energy Survey year 3 data and the thin disk scale height of early L types
• Dwarf AGNs from Optical Variability for the Origins of Seeds (DAVOS): Insights from the Dark Energy Survey Deep Fields
• Discovery of a Candidate Binary Supermassive Black Hole in a Periodic Quasar from Circumbinary Accretion Variability
• Finding the brightest cosmic beacons in the Southern Hemisphere
• Identifying RR Lyrae Variable Stars in Six Years of the Dark Energy Survey
• The spectroscopic follow-up of the QUBRICS bright quasar survey
• The QUEST-La Silla AGN Variability Survey: selection of AGN candidates through optical variability
• Quasar Lenses and Galactic Streams: Outlier Selection and GAIA Multiplet Detection
• Identifying Tidal Disruption Events via Prior Photometric Selection of Their Preferred Hosts
• Finding quadruply imaged quasars with machine learning. I. Methods
• Dark Energy Survey Identification of A Low-Mass Active Galactic Nucleus at Redshift 0.823 from Optical Variability
• Long-term variability of the composite galaxy SDSS J103911-000057: A candidate of true Type-2 AGN
• Very Large Array imaging rules out precessing radio jets in three DES$-$SDSS-selected candidate periodic quasars
• Observational window effects on multi-object Reverberation Mapping
• OzDES Reverberation Mapping Program: Stacking analysis with H$\beta$, Mg II and C IV
• Unlocking AGN Variability with Custom ZTF Photometry for High-Fidelity Light Curves and Robust Selection