Metals in the IGM approaching the re-ionization epoch: results from X-shooter at the VLT

Abstract

We present the results of observations taken with the X-shooter spectrograph devoted to the study of quasars at z ~ 6. This paper focuses on the properties of metals at high redshift traced, in particular, by the C IV doublet absorption systems. Six objects were observed with resolutions ~27 and 34 km/s in the visual, and 37.5 and 53.5 km/s in the near infrared. We detected 102 C IV lines in the range: 4.35 < z < 6.2 of which 27 are above z ~ 5. Thanks to the characteristics of resolution and spectral coverage of X-shooter, we could also detect 25 Si IV doublets associated with the C IV at z>5. The column density distribution function of the C IV line sample is observed to evolve in redshift for z>~ 5.3, with respect to the normalization defined by low redshift (1.5 < z <4) C IV lines. This behaviour is reflected in the redshift evolution of the C IV cosmic mass density, Omega_CIV, of lines with column density in the range 13.4 < log N(C IV) < 15, which is consistent with a drop of a factor of ~2 for z>~ 5.3. Considering only the stronger C IV lines (13.8 < log N(CIV) < 15), Omega_CIV gently rises by a factor of ~10 between z ~ 6.2 and z~ 1.5 with a possible flattening toward z ~ 0. The increase is well fitted by a power law: Omega_CIV = (2+-1)x10^{-8} [(1+z)/4]^{-3.1+-0.1}. An insight into the properties of the C IV absorbers and their evolution with redshift is obtained by comparing the observed column densities of associated C IV, Si IV and C II absorptions with the output of a set of CLOUDY photo-ionization models. As already claimed by cosmological simulations, we find that C IV is a good tracer of the metallicity in the low-density intergalacitc medium gas at z ~ 5-6 while at z ~ 3 it arises in gas with over density delta ~100.

Accepted for publication in MNRAS. Minor changes with respect to previous version (typos, references)

References in corpus (16)

• A luminous quasar at a redshift of z = 7.085
• Observational constraints on Cosmic Reionization
• Cosmological Simulations of Intergalactic Medium Enrichment from Galactic Outflows
• Four quasars above redshift 6 discovered by the Canada-France High-z Quasar Survey
• Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical Abundances, Black Hole Masses, and MgII Absorption
• The Low-z Intergalactic Medium. III. HI and Metal Absorbers at z<0.4
• Black hole masses and enrichment of z ~ 6 SDSS quasars
• A downturn in intergalactic CIV as redshift 6 is approached
• A Flat Photoionization Rate at 2<z<4.2: Evidence for a Stellar-Dominated UV Background and Against a Decline of Cosmic Star Formation Beyond z~3
• Intergalactic CIV absorption at redshifts 5.4 to 6
• High Redshift Intergalactic C IV Abundance Measurements from the Near-Infrared Spectra of Two z~6 QSOs
• Evidence for strong evolution of the cosmic star formation density at high redshift
• On the minimum mass of reionization sources
• Spectral shape of the UV ionizing background and HeII absorption at redshifts 1.8 < z < 2.9
• Precious Metals in SDSS Quasar Spectra II: Tracking the Evolution of Strong, 0.4 < z < 2.3 MgII Absorbers with Thousands of Systems
• Optical-NIR spectra of quasars close to reionization (z~ 6)

Cited by in corpus (85)

• De Re Metallica: The cosmic chemical evolution of galaxies
• Evidence of patchy hydrogen reionization from an extreme Ly$\alpha$ trough below redshift six
• The Evolution of the Intergalactic Medium
• The Cosmic Baryon and Metal Cycles
• New constraints on Lyman-α opacity with a sample of 62 quasars at z > 5.7
• New synthesis models of consistent extragalactic background light over cosmic time
• EIGER I. a large sample of [OIII]-emitting galaxies at $5.3<z<6.9$ and direct evidence for local reionization by galaxies
• Reionization and high-redshift galaxies: the view from quasar absorption lines
• Simulating cosmic metal enrichment by the first galaxies
• Interpreting ALMA Observations of the ISM During the Epoch of Reionisation
• Lyα emission line reconstruction for high-$z$ QSOs
• The Global History of Reionisation
• A physical model for [CII] line emission from galaxies
• XQ-100: A legacy survey of one hundred 3.5 < z < 4.5 quasars observed with VLT/XSHOOTER
• Cosmic distribution of highly ionized metals and their physical conditions in the EAGLE simulations
• Simulating Groups and the IntraGroup Medium: The Surprisingly Complex and Rich Middle Ground Between Clusters and Galaxies
• The ESO UVES Advanced Data Products Quasar Sample - VI. Sub-Damped Lyman-$\alpha$ Metallicity Measurements and the Circum-Galactic Medium
• ALMA suggests outflows in z~5.5 galaxies
• Constraining the contribution of active galactic nuclei to reionisation
• 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
• Reionization in Technicolor
• New Constraints on Quasar Evolution: Broad Line Velocity Shifts over $1.5\lesssim z\lesssim 7.5$
• Tracing the Cosmic Metal Evolution in the Low-Redshift Intergalactic Medium
• Tracing Outflowing Metals in Simulations of Dwarf and Spiral Galaxies
• Nature of the Absorbing Gas associated with a Galaxy Group at z~0.4
• Heavy Element Absorption Systems at $5.0<z<6.8$: Metal-Poor Neutral Gas and a Diminishing Signature of Highly Ionized Circumgalactic Matter
• The contribution from stars stripped in binaries to cosmic reionization of hydrogen and helium
• Outflows and extended [CII] halos in high redshift galaxies
• Detecting and Characterizing Young Quasars II: Four Quasars at $z\sim 6$ with Lifetimes $<10^4$ years
• Testing the effect of galactic feedback on the IGM at z ~ 6 with metal-line absorbers
• A study of the circum-galactic medium at z ~ 0.6 using DLA-galaxies
• Properties of QSO Metal Line Absorption Systems at High Redshifts: Nature and Evolution of the Absorbers and New Evidence on Escape of Ionizing Radiation from Galaxies
• The Soft, Fluctuating UVB at $z\sim 6$ as Traced by C IV, SiIV, and CII
• A deep search for metals near redshift 7: the line-of-sight towards ULAS J1120+0641
• The Reionization of Carbon
• Physical properties of the first quasars
• The role of galaxies and AGN in reionizing the IGM - II: metal-tracing the faint sources of reionization at $5\lesssim z\lesssim 6$
• The Growth and Enrichment of the Intragroup Gas
• The primordial environment of supermassive black holes (II): deep Y and J band images around the z=6.3 quasar SDSS J1030+0524
• A Community Science Case for E-ELT HIRES
• Efficient cold outflows driven by cosmic rays in high redshift galaxies and their global effects on the IGM
• The XQR-30 Metal Absorber Catalog: 778 Absorption Systems Spanning 2 < z < 6.5
• The CGM and IGM at z$\sim$5: metal budget and physical connection
• Spatially Resolved Metal Gas Clouds
• The evolution of the Si IV content in the Universe from the epoch of reionization to cosmic noon
• Mapping metals at high redshift with far-infrared lines
• The circumgalactic medium of high redshift galaxies
• KODIAQ-Z: Metals and Baryons in the Cool Intergalactic and Circumgalactic Gas at 2.2<z<3.6
• Evolution of CIV Absorbers I. The Cosmic Incidence
• 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 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
• Faint LAEs near z>4.7 CIV absorbers revealed by MUSE
• Extended Ly$\alpha$ emission around quasars with eclipsing damped Ly$\alpha$ systems
• The comoving mass density of MgII from $z\sim 2$ to $5.5$
• Simulated metal and HI absorption lines at the conclusion of Reionization
• Aligned metal absorbers and the ultraviolet background at the end of reionization
• Evidence of Pop~III stars' chemical signature in neutral gas at z~6. A study based on the E-XQR-30 spectroscopic sample
• Constraining the epoch of reionization from the observed properties of the high-z Universe
• MUSE unravels the ionisation and origin of metal enriched absorbers in the gas halo of a z = 2.92 radio galaxy
• Probing Reionization and Early Cosmic Enrichment with the MgII Forest
• The effects of binary stars on galaxies and metal-enriched gas during reionization
• Metal Enrichment in the Reionization Epoch
• Probing the Metal Enrichment of the Intergalactic Medium at $z=5-6$ Using the Hubble Space Telescope
• ColdSIM predictions of [C II] emission in primordial galaxies
• Constraining IGM enrichment and metallicity with the C IV forest correlation function
• A framework to measure the properties of intergalactic metal systems with two-point flux statistics
• Theoretical study of an LAE-CIV absorption pair at z = 5.7
• The environments and hosts of metal absorption at z>5
• Probing the nature of Dark Matter through the metal enrichment of the intergalactic medium
• What can distant galaxies teach us about massive stars?
• An Improved Treatment of Cosmological Intergalactic Medium Evolution
• A Global Census of Metals in the Universe
• A census of H$\alpha$ emitters in the intergalactic medium of the NGC 2865 system
• Cospatial 21 cm and metal-line absorbers in the epoch of reionization -- I : Incidence and observability
• A high-redshift quasar absorber without CIV - a galactic outflow caught in the act?
• The clustering of C IV and Si IV at the end of reionisation: A perspective from the E-XQR-30 survey
• The multiple coherence scales of C IV at cosmic noon
• Declining metallicity and extended HeII in the outflow of an epoch of reionization analogue galaxy
• Galaxy Proximate Damped Lyman-Alpha Systems and HI Reionization Topology in TECHNICOLOR DAWN
• Modelling intergalactic low ionisation metal absorption line systems near the epoch of reionization
• Can UVB variations reconcile simulated quasar absorption lines at high redshift?
• Mapping the z>=5 SiIV Column Density Distribution onto the Galaxy Stellar Mass Function Using the Cumulative Absorption Cross Section