Probing Large-scale UV Background Inhomogeneity Associated with Quasars using Metal Absorption

Abstract

We study large-scale UV background inhomogeneity in three-dimensions associated with the observed quasar populations at high redshift. We do this by measuring metal absorption through quasar absorption spectrum stacking as a function distance to closest quasar in SDSS-IV/eBOSS on 10s of comoving megaparsec scales. We study both intergalactic medium absorbers and mixed circumgalactic medium absorbers and probe absorption in O VI, C IV, and Si IV, and Si III. Overall stronger high ionization species absorption is seen closer to quasars at $2.4<z<3.1$. O VI absorption shows a particularly strong change, with effects in C IV evident in some cases, and more marginal effects in Si III and Si IV. We further study $2.05<z<2.4$ (with weak signs of increasing homogeneity with time) and explore the study of metal absorption as a function of integrated SDSS-r band flux quasar flux (yielding consistent but less significant results). While the metal absorption does show sensitivity to large-scale 3D quasar proximity, the current incomplete quasar samples limit detailed interpretation. This work does, however, demonstrate that UV background inhomogeneities exist on scales of several 10s of comoving megaparsecs associated with quasars and that they can be measured with precision by examining metal absorption in the intergalactic medium.

arXiv comment12 pages, Appendix:2 pages, 13 figures, 4 tables, submitted to MNRAS

References in corpus (63)

• Astropy: A Community Python Package for Astronomy
• Planck 2015 results. XIII. Cosmological parameters
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
• Sloan Digital Sky Survey IV: Mapping the Milky Way, Nearby Galaxies, and the Distant Universe
• Radiative Transfer in a Clumpy Universe: II. The Utraviolet Extragalactic Background
• The Sixteenth Data Release of the Sloan Digital Sky Surveys: First Release from the APOGEE-2 Southern Survey and Full Release of eBOSS Spectra
• The DESI Experiment Part I: Science,Targeting, and Survey Design
• Radiative transfer in a clumpy universe: IV. New synthesis models of the cosmic UV/X-ray background
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Overview and Early Data
• A New Calculation of the Ionizing Background Spectrum and the Effects of HeII Reionization
• Extragalactic Background Light Inferred from AEGIS Galaxy SED-type Fractions
• The Sloan Digital Sky Survey Quasar Catalog: Sixteenth Data Release
• Metallicity of the intergalactic medium using pixel statistics. II. The distribution of metals as traced by C IV
• The Gaseous Environment of High-z Galaxies: Precision Measurements of Neutral Hydrogen in the Circumgalactic Medium of z ~ 2-3 Galaxies in the Keck Baryonic Structure Survey
• Quasar Clustering and the Lifetime of Quasars
• The Direct Detection of Lyman-Continuum Emission from Star-forming Galaxies at z~3
• Baryon acoustic oscillations from the complete SDSS-III Ly$\alpha$-quasar cross-correlation function at $z=2.4$
• The first ultraviolet quasar stacked spectrum at z=2.4 from WFC3
• Baryon acoustic oscillations from the cross-correlation of Ly$\alpha$ absorption and quasars in eBOSS DR14
• A Direct Precision Measurement of the Intergalactic Lyman-alpha Opacity at 2<z<4.2
• The Distribution of Column Densities and b Values in the Lyman-Alpha Forest
• A Composite Extreme Ultraviolet QSO Spectrum from the Far Ultraviolet Spectroscopic Explorer
• HETDEX pilot survey for emission-line galaxies - I. Survey design, performance, and catalog
• J-PAS: The Javalambre-Physics of the Accelerated Universe Astrophysical Survey
• HST-COS Observations of AGN. I. Ultraviolet Composite Spectra of the Ionizing Continuum and Emission Lines
• HST-COS Observations of AGN. II. Extended Survey of Ultraviolet Composite Spectra from 159 Active Galactic Nuclei
• The Column Density Distribution and Continuum Opacity of the Intergalactic and Circumgalactic Medium at Redshift <z>=2.4
• A Principal Component Analysis of quasar UV spectra at z~3
• Ionizing radiation fluctuations and large-scale structure in the Lyman-alpha forest
• Metallicity of the intergalactic medium using pixel statistics: III. Silicon
• Early and Extended Helium Reionization Over More Than 600 Million Years of Cosmic Time
• Caught in the act: a helium-reionizing quasar near the line of sight to Q0302-003
• The Extended Baryon Oscillation Spectroscopic Survey: Variability Selection and Quasar Luminosity Function
• Metallicity of the intergalactic medium using pixel statistics: IV. Oxygen
• From the far-ultraviolet to the far-infrared -- galaxy emission at $0\le z\le 10$ in the Shark semi-analytic model
• The History and Morphology of Helium Reionization
• Predicting QSO Continua in the Ly Alpha Forest
• The BOSS Lyman-alpha Forest Sample from SDSS Data Release 9
• Deep Learning of Quasar Spectra to Discover and Characterize Damped Lya Systems
• Mean-flux Regulated PCA Continuum Fitting of SDSS Lyman-alpha Forest Spectra
• The Transverse Proximity Effect: A Probe to the Environment, Anisotropy, and Megayear Variability of QSOs
• Probing the Circumgalactic Medium at High-Redshift Using Composite BOSS Spectra of Strong Lyman-alpha Forest Absorbers
• Detection of the Transverse Proximity Effect: Radiative Feedback from Bright QSOs
• AGN proximity zone fossils and the delayed recombination of metal lines
• Probabilistic multi-catalogue positional cross-match
• Reobservation of Close QSO Groups: The Size Evolution and Shape of Lyman Alpha Forest Absorbers
• Statistical Detection of the HeII Transverse Proximity Effect: Evidence for Sustained Quasar Activity for $>$25 Million Years
• The transverse proximity effect in spectral hardness on the line of sight towards HE 2347-4342
• Spectral shape of the UV ionizing background and HeII absorption at redshifts 1.8 < z < 2.9
• The Composite Spectrum of Strong Lyman-alpha Forest Absorbers
• Fluctuations in the Ionizing Background During and After Helium Reionization
• WEAVE-QSO: A Massive Intergalactic Medium Survey for the William Herschel Telescope
• Reionization Bias in High Redshift Quasar Near-Zones
• The Effect of Fluctuations on the Helium-Ionizing Background
• A self-consistent 3D model of fluctuations in the helium-ionizing background
• The mean free path of hydrogen ionizing photons during the epoch of reionization
• A Search for Oxygen in the Low-Density Lyman-alpha Forest Using the Sloan Digital Sky Survey
• He II Lyβ Gunn-Peterson Absorption: New HST Observations, and Theoretical Expectations
• On the Search for Quasar Light Echoes
• Probing Inhomogeneity in the Helium Ionizing UV Background
• The proximity effect on the Lyman alpha forest due to a a foreground QSO

Cited by in corpus (1)

• The wide-field, multiplexed, spectroscopic facility WEAVE: Survey design, overview, and simulated implementation