Ionization near-zones associated with quasars at z ~ 6

Abstract

We analyze the size evolution of HII regions around 27 quasars between z=5.7 to 6.4 ('quasar near-zones' or NZ). We include more sources than previous studies, and we use more accurate redshifts for the host galaxies, with 8 CO molecular line redshifts and 9 MgII redshifts. We confirm the trend for an increase in NZ size with decreasing redshift, with the luminosity normalized proper size evolving as: R_{NZ,corrected} = (7.4 \pm 0.3) - (8.0 \pm 1.1) \times (z-6) Mpc. While derivation of the absolute neutral fraction remains difficult with this technique, the evolution of the NZ sizes suggests a decrease in the neutral fraction of intergalactic hydrogen by a factor ~ 9.4 from z=6.4 to 5.7, in its simplest interpretation. Alternatively, recent numerical simulations suggest that this rapid increase in near-zone size from z=6.4 to 5.7 is due to the rapid increase in the background photo-ionization rate at the end of the percolation or overlap phase, when the average mean free path of ionizing photons increases dramatically. In either case, the results are consistent with the idea that z ~ 6 to 7 corresponds to the tail end of cosmic reionization. The scatter in the normalized NZ sizes is larger than expected simply from measurement errors, and likely reflects intrinsic differences in the quasars or their environments. We find that the near-zone sizes increase with quasar UV luminosity, as expected for photo-ionization dominated by quasar radiation.

16 pages, aas format, 4 figures, to appear in the ApJ letters

References in corpus (16)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Observational constraints on Cosmic Reionization
• The Canada-France High-z Quasar Survey: nine new quasars and the luminosity function at redshift 6
• Four quasars above redshift 6 discovered by the Canada-France High-z Quasar Survey
• A Kiloparsec-Scale Hyper-Starburst in a Quasar Host Less than 1 Gigayear after the Big Bang
• Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars: Chemical Abundances, Black Hole Masses, and MgII Absorption
• Black hole masses and enrichment of z ~ 6 SDSS quasars
• Thermal Emission from Warm Dust in the Most Distant Quasars
• The nature and evolution of the highly ionized near-zones in the absorption spectra of z~6 quasars
• Quasar Proximity Zones and Patchy Reionization
• Imaging Atomic and Highly Excited Molecular Gas in a z=6.42 Quasar Host Galaxy: Copious Fuel for an Eddington-Limited Starburst at the End of Cosmic Reionization
• Millimeter and Radio Observations of z~6 Quasars
• On the Size of HII Regions around High Redshift Quasars
• The Discovery of Three New z>5 Quasars in the AGN and Galaxy Evolution Survey
• A closer look at using quasar near-zones as a probe of neutral hydrogen in the intergalactic medium
• Interpreting the Transmission Windows of Distant Quasars

Cited by in corpus (90)

• A luminous quasar at a redshift of z = 7.085
• An ultra-luminous quasar with a twelve-billion-solar-mass black hole at redshift 6.30
• Hydrogen Epoch of Reionization Array (HERA)
• 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 Pan-STARRS1 distant z>5.6 quasar survey: more than 100 quasars within the first Gyr of the universe
• Eddington-limited accretion and the black hole mass function at redshift 6
• Reionization and the Cosmic Dawn with the Square Kilometre Array
• The Final SDSS High-Redshift Quasar Sample of 52 Quasars at z>5.7
• Physical properties of 15 quasars at $z\gtrsim 6.5$
• An ALMA [CII] survey of 27 quasars at z>5.94
• Hydrogen reionisation ends by $z=5.3$: Lyman-$\alpha$ optical depth measured by the XQR-30 sample
• Full-Data Results of Hubble Frontier Fields: UV Luminosity Functions at $z\sim 6-10$ and a Consistent Picture of Cosmic Reionization
• Planck intermediate results. XLVII. Planck constraints on reionization history
• How neutral is the intergalactic medium surrounding the redshift z=7.085 quasar ULAS J1120+0641?
• Subaru high-z exploration of low-luminosity quasars (SHELLQs). I. Discovery of 15 quasars and bright galaxies at 5.7 < z < 6.9
• New constraints on Lyman-α opacity with a sample of 62 quasars at z > 5.7
• Measurements of the UV background at 4.6 < z < 6.4 using the quasar proximity effect
• Hubble Frontier Fields First Complete Cluster Data: Faint Galaxies at $z\sim 5-10$ for UV Luminosity Functions and Cosmic Reionization
• The identification of z-dropouts in Pan-STARRS1: three quasars at 6.5<z<6.7
• The mean free path of ionizing photons at 5 < z < 6: evidence for rapid evolution near reionization
• Star formation and the interstellar medium in z>6 UV-luminous Lyman-break galaxies
• Star formation rate and dynamical mass of 10^8 solar mass black hole host galaxies at redshift 6
• 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
• Evidence of Gunn-Peterson damping wings in high-z quasar spectra: strengthening the case for incomplete reionization
• Near-zone sizes and the rest frame extreme ultra-violet spectral index of the highest redshift quasars
• Redshift 6.4 host galaxies of 10^8 solar mass black holes: low star formation rate and dynamical mass
• Eight new luminous z > 6 quasars selected via SED model fitting of VISTA, WISE and Dark Energy Survey Year 1 Observations
• Measurements of the z ~ 6 Intergalactic Medium Optical Depth and Transmission Spikes Using a New z > 6.3 Quasar Sample
• Improved measurements of the intergalactic medium temperature around quasars: possible evidence for the initial stages of He-II reionisation at z~6
• Constraining the radio-loud fraction of quasars at z>5.5
• Lyα emission line reconstruction for high-$z$ QSOs
• The Global History of Reionisation
• The REQUIEM Survey I: A Search for Extended Ly-Alpha Nebular Emission Around 31 z>5.7 Quasars
• The first (nearly) model-independent constraint on the neutral hydrogen fraction at z~5--6
• Dust emission in an accretion-rate-limited sample of z>6 quasars
• Detecting and Characterizing Young Quasars I: Systemic Redshifts and Proximity Zones Measurements
• (Nearly) Model-Independent Constraints on the Neutral Hydrogen Fraction in the Intergalactic Medium at $z\sim 5-7$ Using Dark Pixel Fractions in Ly$\alpha$ and Ly$\beta$ Forests
• The discovery of a highly accreting, radio-loud quasar at z=6.82
• High-Redshift Metals. II. Probing Reionization Galaxies with Low-Ionization Absorption Lines at Redshift Six
• Euclid preparation: V. Predicted yield of redshift 7<z<9 quasars from the wide survey
• XQR-30: the ultimate XSHOOTER quasar sample at the reionization epoch
• A first direct measurement of the intergalactic medium temperature around a quasar at z=6
• Revisiting the Lyman Continuum Escape Crisis: Predictions for z > 6 from Local Galaxies
• DES J0454-4448: Discovery of the First Luminous z > 6 Quasar from the Dark Energy 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
• Three Lyman-alpha emitting galaxies within a quasar proximity zone at z=5.8
• Discovery of Eight z ~ 6 Quasars in the Sloan Digital Sky Survey Overlap Regions
• Reionization history constraints from neural network based predictions of high-redshift quasar continua
• Detecting and Characterizing Young Quasars II: Four Quasars at $z\sim 6$ with Lifetimes $<10^4$ years
• Time-dependent behaviour of quasar proximity zones at $z\sim 6$
• A comparison of quasar emission reconstruction techniques for $z\ge 5.0$ Lyman-$\alpha$ and Lyman-$\beta$ transmission
• No excess of bright galaxies around the redshift 7.1 quasar ULAS J1120+0641
• A deep search for metals near redshift 7: the line-of-sight towards ULAS J1120+0641
• Probing the end of reionization with the near-zones of z > 6 QSOs
• Two more, bright, z > 6 quasars from VST ATLAS and WISE
• Cosmic Reionization On Computers. Properties of the Post-reionization IGM
• Discovery of a Radio-Selected z ~ 6 Quasar
• Observing the first galaxies
• The XQR-30 Metal Absorber Catalog: 778 Absorption Systems Spanning 2 < z < 6.5
• The Pan-STARRS1 $\mathbf{z}>5.6$ Quasar Survey: III. The $\mathbf{z}\approx 6$ Quasar Luminosity Function
• He II Proximity Effect and the Lifetime of Quasars
• Evidence for Short $\sim 1$ Myr Lifetimes from the He II Proximity Zones of $z\sim 4$ Quasars
• Thermal constraints on the reionisation of hydrogen by population-II stellar sources
• The Near and Mid-infrared photometric properties of known redshift $z\ge 5$ Quasars
• A Quasar Discovered at redshift 6.6 from Pan-STARRS1
• The need for obscured supermassive black hole growth to explain quasar proximity zones in the epoch of reionization
• First study of reionization in the Planck 2015 normalized closed $\Lambda$CDM inflation model
• The Distribution and Evolution of Quasar Proximity Zone Sizes
• Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). XI. Proximity Zone Analysis for Faint Quasar Spectra at z~6
• Dating individual quasars with the HeII proximity effect
• Quasars as probes of cosmological reionization
• New quasar proximity zone size measurements at $z\sim 6$ using the enlarged XQR-30 sample
• Quasar Factor Analysis -- An Unsupervised and Probabilistic Quasar Continuum Prediction Algorithm with Latent Factor Analysis
• The physical origin for spatially large scatter of IGM opacity at the end of reionization: the IGM Ly$\alpha$ opacity-galaxy density relation
• X-ray emission from a rapidly accreting narrow-line Seyfert 1 galaxy at z=6.56
• Ionization bias and the ghost proximity effect near $z\gtrsim 6$ quasars in the shadow of proximate absorption systems
• Deep LBT/LUCI Spectroscopy of a Lyman-alpha Emitter Candidate at z ~ 7.7
• Discovery of a very Lyman-$\alpha$-luminous quasar at z=6.62
• Detecting the Highest Redshift (z > 8) QSOs in a Wide, Near Infrared Slitless Spectroscopic Survey
• Radio-loud fraction of z>6 quasars
• Probing quasar lifetimes with proximate $21$-centimetre absorption in the diffuse intergalactic medium at redshifts $z\ge 6$
• Reality or Mirage? Observational Test and Implications for the Claimed Extremely Magnified Quasar at $z=6.3$
• Recovering Density Fields inside Quasar Proximity Zones at $z\sim 6$
• Subaru medium-resolution spectra of a QSO at z=6.62: Three reionization tests
• High-$z$ radio Quasars in RACS I: Selection, identification, and multi-wavelength properties
• Signature of the interaction between dark sectors in the reionization process
• The Contribution of AGN Accretion Disks to Hydrogen Reionization
• An Estimate of the Impact of Reionization on Supermassive Black Hole Growth