Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ∼ 6 Quasars. II. A Sample of 19 Quasars

  title={Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ∼ 6 Quasars. II. A Sample of 19 Quasars},
  author={Xiaohui Fan and Michael A. Strauss and Robert H. Becker and Richard L. White and James E. Gunn and Gillian R. Knapp and Gordon T. Richards and Donald P. Schneider and Jonathan Brinkmann and Masataka Fukugita},
  journal={The Astronomical Journal},
  pages={117 - 136}
We study the evolution of the ionization state of the intergalactic medium (IGM) at the end of the reionization epoch using moderate-resolution spectra of a sample of 19 quasars at 5.74 < zem < 6.42 discovered in the Sloan Digital Sky Survey. Three methods are used to trace IGM properties: (1) the evolution of the Gunn-Peterson (GP) optical depth in the Lyα, Lyβ, and Lyγ transitions; (2) the distribution of lengths of dark absorption gaps; and (3) the size of H II regions around luminous… 

The Evolution of the He ii-ionizing Background at Redshifts 2.3 < z < 3.8 Inferred from a Statistical Sample of 24 HST/COS He ii Lyα Absorption Spectra

We present measurements of the large-scale (≈40 comoving Mpc) effective optical depth of He ii Lyα absorption, , at 2.54 < z < 3.86 toward 16 He ii-transparent quasars observed with the Cosmic

Texas Spectroscopic Search for Lyα Emission at the End of Reionization I. Constraining the Lyα Equivalent-width Distribution at 6.0 < z < 7.0

The distribution of Lyα emission is a presently accessible method for studying the state of the intergalactic medium (IGM) into the reionization era. We carried out deep spectroscopic observations in

Measurements of the z ∼ 6 Intergalactic Medium Optical Depth and Transmission Spikes Using a New z > 6.3 Quasar Sample

We report new measurements of the intergalactic medium (IGM) Lyα and Lyβ effective optical depth at 5.3 < z < 6.5, using a new sample of quasar sight lines including 32 quasars at 6.308 ≤ z ≤ 7.00.

The Evolution of Optical Depth in the Lyα Forest: Evidence Against Reionization at z~6*

We examine the evolution of the IGM Lyα optical depth distribution using the transmitted flux probability distribution function (PDF) in a high-resolution sample of 55 QSOs spanning absorption

Lyman continuum escape fraction and mean free path of hydrogen ionizing photons for bright z ∼ 4 QSOs from SDSS DR14

Context. One of the main challenges in observational cosmology is related to the redshift evolution of the average hydrogen (HI) ionization in the Universe, as evidenced by the changing in ionization

The Opacity of the Intergalactic Medium Measured along Quasar Sightlines at z ∼ 6

We publicly release a new sample of 34 medium resolution quasar spectra at 5.77 ≤ zem ≤ 6.54 observed with the Echellette Spectrograph and Imager on the Keck telescope. This quasar sample represents

The observed ionization rate of the intergalactic medium and the ionizing emissivity at z≥ 5: evidence for a photon-starved and extended epoch of reionization

Galaxies and quasars are thought to provide the bulk of the photons responsible for ionizing the hydrogen in the intergalactic medium (IGM). We use a large set of hydrodynamical simulations, combined

The role of galaxies and AGN in reionizing the IGM – III. IGM–galaxy cross-correlations at z ∼ 6 from eight quasar fields with DEIMOS and MUSE

We present improved results of the measurement of the correlation between galaxies and the intergalactic medium transmission at the end of reionization. We have gathered a sample of 13

A first direct measurement of the intergalactic medium temperature around a quasar at z = 6

The thermal state of the intergalactic medium (IGM) provides an indirect probe of both the HI and He II reionization epochs. Current constraints on the IGM temperature from the Lyα forest are

The contribution of high-redshift galaxies to cosmic reionization: New results from deep WFC3 imaging of the Hubble Ultra Deep Field

We have searched for star-forming galaxies at z≈ 7–10 by applying the Lyman-break technique to newly released Y-, J- and H-band images (1.1, 1.25 and 1.6 μm) from Wide Field Camera 3 (WFC3) on the



Evolution of the Ionizing Background and the Epoch of Reionization from the Spectra of z ∼ 6 Quasars

We study the process of cosmic reionization and estimate the ionizing background in the intergalactic medium (IGM) using the Lyman series absorption in the spectra of the four quasars at 5.7 < z <

Evidence for Reionization at z ∼ 6: Detection of a Gunn-Peterson Trough in a z = 6.28 Quasar

We present moderate-resolution Keck spectroscopy of quasars at z = 5.82, 5.99, and 6.28, discovered by the Sloan Digital Sky Survey (SDSS). We find that the Lyα absorption in the spectra of these

The Detectability of High-Redshift Lyα Emission Lines prior to the Reionization of the Universe

For a source of Lyα radiation embedded in a neutral intergalactic medium (IGM) prior to the reionization epoch, the Lyα emission line is strongly suppressed by the intervening IGM. The damping wing

Evolution of the Ionizing Radiation Background and Star Formation in the Aftermath of Cosmological Reionization

The temporal evolution of the ionizing UV background radiation field at high redshift provides a probe of the evolution of the early star formation rate. By comparing the observed levels of

A Uniform Analysis of the Lyα Forest at z = 0-5. V. The Extragalactic Ionizing Background at Low Redshift

In Paper III of our series, "A Uniform Analysis of the Lyα Forest at z = 0-5," we presented a set of 270 quasar spectra from the archives of the Faint Object Spectrograph (FOS) on the Hubble Space

On the Threshold of the Reionization Epoch

Discovery of the cosmic reionization epoch would represent a significant milestone in cosmology. We present Keck spectroscopy of the quasar SDSS 1044-0125, at z = 5.73. The spectrum shows a dramatic

Constraints on the ionization sources of the high‐redshift intergalactic medium

Constraints on the ionization structure of the intergalactic medium (IGM) are derived as directly imposed by observations in conjunction with the results of numerical simulations for structure

VLT Optical and Near-Infrared Observations of the z = 6.28 Quasar SDSS J1030+0524

We present new VLT spectroscopic observations of the most distant quasar known, SDSS J1030+0524 at z = 6.28, which was recently discovered by the Sloan Digital Sky Survey. We confirm the presence of

A Galaxy at z = 6.545 and Constraints on the Epoch of Reionization

We report the discovery of a Lyα-emitting galaxy at redshift z = 6.545 serendipitously identified in the course of spectroscopic follow-up of hard X-ray sources on behalf of the Serendipitous

Probing the Reionization History Using the Spectra of High-Redshift Sources

We quantify and discuss the footprints of neutral hydrogen in the intergalactic medium (IGM) on the spectra of high-redshift (z ~ 6) sources, using mock spectra generated from hydrodynamical