The role of galaxies and AGN in reionizing the IGM - II: metal-tracing the faint sources of reionization at $5\lesssim z\lesssim 6$

Abstract

We present a new method to study the contribution of faint sources to the UV background using the 1D correlation of metal absorbers with the intergalactic medium (IGM) transmission in a Quasi Stellar Object (QSO) sightline. We take advantage of a sample of $25$ high signal-to-noise ratio QSO spectra to retrieve $150$ triply-ionised carbon (\cfour) absorbers at $4.5\lesssim z\lesssim 6.2$, of which $37$ systems whose expected H{~\small I} absorption lie in the Lyman-$\alpha$ forest. We derive improved constraints on the cosmic density of \cfour \,at $4.3<z<6.2$ and infer from abundance-matching that \cfour \,absorbers trace $M_{\text{UV}}\lesssim -16$ galaxies. Correlation with the Lyman-$\alpha$ forest of the QSOs indicates that these objects are surrounded by a highly opaque region at $r\lesssim 5$ cMpc/h followed by an excess of transmission at $r\gtrsim 10$ cMpc/h detected at $2.7\sigma$. This is in contrast to equivalent measurements at lower redshifts where only the opaque trough is detected. We interpret this excess as a statistical enhancement of the local photoionisation rate due to clustered faint galaxies around the \cfour \,absorbers. Using the analytical framework described in Paper I of this series, we derive a constraint on the average product of the escape fraction and the Lyman continuum photon production efficiency of the galaxy population clustered around the \cfour \,absorbers, $\log ⟨f_{\text{esc}}{\xi }_{\text{ion}}⟩/[\mathrm{er}{\mathrm{g}}^{-1}\mathrm{Hz}]=25.01_{-0.19}^{+0.30}$. This implies that faint galaxies beyond the reach of current facilities may have harder radiation fields and/or larger escape fractions than currently detected objects at the end of the reionisation epoch.

arXiv comment20 pages, 11 figures, accepted for publication by MNRAS. Updated version to match the published version. Results remain unchanged

References in corpus (87)

• emcee: The MCMC Hammer
• Planck 2015 results. XIII. Cosmological parameters
• A luminous quasar at a redshift of z = 7.085
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• Astrophysics Source Code Library
• UV Luminosity Functions at redshifts z~4 to z~10: 10000 Galaxies from HST Legacy Fields
• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• An 800-million-solar-mass black hole in a significantly neutral Universe at redshift 7.5
• The Structure and Kinematics of the Circum-Galactic Medium from Far-UV Spectra of z~2-3 Galaxies
• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Warm Dark Matter as a solution to the small scale crisis: new constraints from high redshift Lyman-alpha forest data
• Optimal Techniques in Two-dimensional Spectroscopy: Background Subtraction for the 21st Century
• UV Luminosity Functions at z~4, 5, and 6 from the HUDF and other Deep HST ACS Fields: Evolution and Star Formation History
• New Constraints on Cosmic Reionization from the 2012 Hubble Ultra Deep Field Campaign
• Model-independent evidence in favor of an end to reionization by z~6
• The Abundance of Star-Forming Galaxies in the Redshift Range 8.5 to 12: New Results from the 2012 Hubble Ultra Deep Field Campaign
• Galaxies and Intergalactic Matter at Redshift z~3: Overview
• The Lyman-alpha Forest Power Spectrum from the Sloan Digital Sky Survey
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• The Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars within the first Gyr of the universe
• A Survey of z>5.7 Quasars in the Sloan Digital Sky Survey III: Discovery of Five Additional Quasars
• ESI, a new Keck Observatory echellette spectrograph and imager
• Directly Observing the Galaxies Likely Responsible for Reionization
• Lyman-alpha and CIII] Emission in z=7-9 Galaxies: Accelerated Reionization Around Luminous Star Forming Systems?
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• Dust in the reionization era: ALMA observations of a $z$=8.38 Galaxy
• Faint AGNs at z>4 in the CANDELS GOODS-S field: looking for contributors to the reionization of the Universe
• Discovery of three z>6.5 quasars in the VISTA Kilo-degree Infrared Galaxy (VIKING) survey
• Full-Data Results of Hubble Frontier Fields: UV Luminosity Functions at $z\sim 6-10$ and a Consistent Picture of Cosmic Reionization
• The Connection Between Galaxies and Intergalactic Absorption Lines at Redshift 2<z<3
• Baryon acoustic oscillations from the complete SDSS-III Ly$\alpha$-quasar cross-correlation function at $z=2.4$
• Large Lyman-alpha opacity fluctuations and low CMB tau in models of late reionization with large islands of neutral hydrogen extending to z<5.5
• Spectroscopic detection of CIV in a galaxy at z=7.045: Implications for the ionizing spectra of reionization-era galaxies
• Keeping the Universe ionised: Photo-heating and the clumping factor of the high-redshift intergalactic medium
• The Extreme Faint End of the UV Luminosity Function at $z\sim 6$ Through Gravitational Telescopes: a comprehensive assessment of strong lensing uncertainties
• Z > 7 galaxies with red Spitzer/IRAC [3.6]-[4.5] colors in the full CANDELS data set: the brightest-known galaxies at Z ~ 7-9 and a probable spectroscopic confirmation at Z=7.48
• Evidence for non-evolving FeII/MgII ratios in rapidly accreting z~6 QSOs
• Subaru high-z exploration of low-luminosity quasars (SHELLQs). I. Discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9
• The Lyman-Continuum Photon Production Efficiency xi_{ion} of z~4-5 Galaxies from IRAC-based Halpha Measurements: Implications for the Escape Fraction and Cosmic Reionization
• New constraints on Lyman-α opacity with a sample of 62 quasars at z > 5.7
• The Giant Gemini GMOS survey of z>4.4 quasars - I. Measuring the mean free path across cosmic time
• The Ly-alpha Properties of Faint Galaxies at z2-3 with Systemic Redshifts and Velocity Dispersions from Keck-MOSFIRE
• Consistent modelling of the meta-galactic UV background and the thermal/ionization history of the intergalactic medium
• Metal-line absorption around $z\approx$2.4 star-forming galaxies in the Keck Baryonic Structure Survey
• Hubble Frontier Fields First Complete Cluster Data: Faint Galaxies at $z\sim 5-10$ for UV Luminosity Functions and Cosmic Reionization
• New redshift z ~ 9 galaxies in the Hubble Frontier Fields: Implications for early evolution of the UV luminosity density
• No evidence for a significant AGN contribution to cosmic hydrogen reionization
• The SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Baryon Acoustic Oscillations at redshift of 0.72 with the DR14 Luminous Red Galaxy Sample
• Reionization and high-redshift galaxies: the view from quasar absorption lines
• A downturn in intergalactic CIV as redshift 6 is approached
• Evolution of Stellar-to-Halo Mass Ratio at z=0-7 Identified by Clustering Analysis with the Hubble Legacy Imaging and Early Subaru/Hyper Suprime-Cam Survey Data
• A spectroscopic search for AGN activity in the reionization era
• Hydrogen and Metal Line Absorption Around Low-Redshift Galaxies in Cosmological Hydrodynamic Simulations
• APM z>4 QSO Survey: Spectra and Intervening Absorption Systems
• A Hard Ionizing Spectrum in z=3-4 Ly-alpha Emitters with Intense [OIII] Emission: Analogs of Galaxies in the Reionization Era?
• Large scale opacity fluctuations in the Lyman alpha forest: evidence for QSOs dominating the ionising UV background at z ~ 5.5-6 ?
• High Redshift Metals I.: The Decline of C IV at z > 5.3
• Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT
• Tracing the Reionization-Epoch Intergalactic Medium with Metal Absorption Lines
• Constraints on the Universal CIV Mass Density at z~6 from Early IR Spectra Obtained with the Magellan FIRE Spectrograph
• Two bright z > 6 quasars from VST ATLAS and a new method of optical plus mid-infra-red colour selection
• On the Contribution of Active Galactic Nuclei to the High-Redshift Metagalactic Ionizing Background
• Evidence for Large-Scale Fluctuations in the Metagalactic Ionizing Background Near Redshift Six
• High-Redshift Metals. II. Probing Reionization Galaxies with Low-Ionization Absorption Lines at Redshift Six
• The Mean Ultraviolet Spectrum of a Representative Sample of Faint z~3 Lyman Alpha Emitters
• Iron and alpha-element Production in the First One Billion Years after the Big Bang
• The discovery of the first luminous z~6 quasar in the UKIDSS Large Area Survey
• Discovery of excess O I absorption towards the z = 6.42 QSO SDSS J1148+5251
• DES J0454-4448: Discovery of the First Luminous z > 6 Quasar from the Dark Energy Survey
• The rise of the C IV mass density at z<2.5
• Reionization in Technicolor
• Discovery of a redshift 6.13 quasar in the UKIRT Infrared Deep Sky Survey
• The Role of Galaxies and AGN in Reionising the IGM - I: Keck Spectroscopy of 5 < z < 7 Galaxies in the QSO Field J1148+5251
• VLT LBG Redshift Survey II: Interactions between galaxies and the IGM at z ~3
• Witnessing galaxy assembly at the edge of the reionization epoch
• Testing the effect of galactic feedback on the IGM at z ~ 6 with metal-line absorbers
• A deep search for metals near redshift 7: the line-of-sight towards ULAS J1120+0641
• Frontier Fields : Combining HST, VLT and Spitzer data to explore the $z$$\sim$8 Universe behind the lensing cluster MACS0416$-$2403
• The CGM and IGM at z$\sim$5: metal budget and physical connection
• Large-scale environment of z~5.7 CIV absorption systems I: projected distribution of galaxies
• Large-scale environment of $z\sim 5.7$ CIV absorption systems -II. Spectroscopy of Lyman-$\alpha$ emitters
• The VLT LBG Redshift Survey - VI. Mapping HI in the proximity of $z\sim 3$ LBGs with X-Shooter
• Broadband distortion modeling in Lyman-$\alpha$ forest BAO fitting
• Simulating the Carbon Footprint of Galactic Halos
• A galaxy as the source of a Civ absorption system close to the epoch of reionization
• Probing the Metal Enrichment of the Intergalactic Medium at $z=5-6$ Using the Hubble Space Telescope
• Optical-NIR spectra of quasars close to reionization (z~ 6)

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• EIGER I. a large sample of [OIII]-emitting galaxies at $5.3<z<6.9$ and direct evidence for local reionization by galaxies
• The THESAN project: properties of the intergalactic medium and its connection to Reionization-era galaxies
• Lyman Radiation Hydrodynamics of Turbulent H II Regions in Molecular Clouds: A Physical Origin of LyC Leakage and the Associated Ly$\alpha$ Spectra
• The Evolution of O I over 3.2 < z < 6.5: Reionization of the Circumgalactic Medium
• XQR-30: the ultimate XSHOOTER quasar sample at the reionization epoch
• Elevated ionizing photon production efficiency in faint high-equivalent-width Lyman-alpha emitters
• New Constraints on Quasar Evolution: Broad Line Velocity Shifts over $1.5\lesssim z\lesssim 7.5$
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• Heavy Element Absorption Systems at $5.0<z<6.8$: Metal-Poor Neutral Gas and a Diminishing Signature of Highly Ionized Circumgalactic Matter
• Outflows and extended [CII] halos in high redshift galaxies
• Host galaxies of high-redshift quasars: supermassive black hole growth and feedback
• A comparison of quasar emission reconstruction techniques for $z\ge 5.0$ Lyman-$\alpha$ and Lyman-$\beta$ transmission
• The role of galaxies and AGN in reionising the IGM -- III : IGM-galaxy cross-correlations at z~6 from 8 quasar fields with DEIMOS and MUSE
• The Predicament of Absorption-Dominated Reionization: Increased Demands on Ionizing Sources
• The XQR-30 Metal Absorber Catalog: 778 Absorption Systems Spanning 2 < z < 6.5
• The evolution of the Si IV content in the Universe from the epoch of reionization to cosmic noon
• Environmental Dependence of Galactic Properties Traced by Ly$\alpha$ Forest Absorption: Diversity among Galaxy Populations
• The Faint Host Galaxies of C IV Absorbers at z > 5
• Examining the Decline in the C IV Content of the Universe over 4.3 < z < 6.3 using the E-XQR-30 Sample
• Constraining the Tail-End of Reionization Using Lyman-$\alpha$ Transmission Spikes
• Faint LAEs near z>4.7 CIV absorbers revealed by MUSE
• Into the Lyα jungle: exploring the circumgalactic medium of galaxies at z ~ 4-5 with MUSE
• Astraeus VI: Hierarchical assembly of AGN and their large-scale effect during the Epoch of Reionization
• The environments and hosts of metal absorption at z>5
• Probing patchy reionisation with JWST: IGM opacity constraints from the Lyman-$\alpha$ forest of galaxies in legacy extragalactic fields
• CoReCon: an open, community-powered collection of Reionization constraints
• A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): JWST Discovers an Overdensity around a Metal Absorption-selected Galaxy at $z\sim 5.5$
• Connection Between Galaxies and HI in the Circumgalactic and Intergalactic Media: Variation According to Galaxy Stellar Mass and Star-formation Activity
• Photometric IGM tomography with Subaru/HSC: the large-scale structure of Ly$\alpha$ emitters and IGM transmission in the COSMOS field at $z\sim 5$
• A unique window into the Epoch of Reionisation: A double-peaked Lyman-$\alpha$ emitter in the proximity zone of a quasar at $z\sim 6.6$
• On the Physical Nature of Ly$\alpha$ Transmission Spikes in High Redshift Quasar Spectra
• Can UVB variations reconcile simulated quasar absorption lines at high redshift?