Redshifted 21cm Observations of High Redshift Quasar Proximity Zones

Abstract

The introduction of low-frequency radio arrays is expected to revolutionize the study of the reionization epoch. Observation of the contrast in redshifted 21cm emission between a large HII region and the surrounding neutral inter-galactic medium (IGM) will be the simplest and most easily interpreted signature. However the highest redshift quasars known are thought to reside in an ionized IGM. Using a semi-analytic model we describe the redshifted 21cm signal from the IGM surrounding quasars discovered using the i-drop out technique (i.e. quasars at z~6). We argue that while quasars at z<6.5 seem to reside in the post overlap IGM, they will still provide valuable probes of the late stages of the overlap era because the light-travel time across a quasar proximity zone should be comparable to the duration of overlap. For redshifted 21cm observations within a 32MHz bandpass, we find that the subtraction of a spectrally smooth foreground will not remove spectral features due to the proximity zone. These features could be used to measure the neutral hydrogen content of the IGM during the late stages of reionization. The density of quasars at z~6 is now well constrained. We use the measured quasar luminosity function to estimate the prospects for discovery of high redshift quasars in fields that will be observed by the Murchison Widefield Array.

arXiv comment14 pages, 9 figures. Accepted for publication in MNRAS

References in corpus (50)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Starburst99: Synthesis Models for Galaxies with Active Star Formation
• Cosmology at Low Frequencies: The 21 cm Transition and the High-Redshift Universe
• Constraining the Evolution of the Ionizing Background and the Epoch of Reionization with z ~ 6 Quasars II: A Sample of 19 Quasars
• In the Beginning: The First Sources of Light and the Reionization of the Universe
• SkyMapper and the Southern Sky Survey
• Reionization of the Inhomogeneous Universe
• A Survey of z>5.7 Quasars in the Sloan Digital Sky Survey IV: Discovery of Seven Additional Quasars
• Hydrodynamic Simulations of Galaxy Formation. II. Photoionization and the Formation of Low Mass Galaxies
• High-Redshift Quasars Found in Sloan Digital Sky Survey Commissioning Data IV: Luminosity Function from the Fall Equatorial Stripe Sampl
• The SDSS Damped Lya Survey: Data Release 3
• A Survey of z>5.7 Quasars in the Sloan Digital Sky Survey III: Discovery of Five Additional Quasars
• Measuring the Small-Scale Power Spectrum of Cosmic Density Fluctuations Through 21 cm Tomography Prior to the Epoch of Structure Formation
• Probing the Ionization State of the Universe at z>6
• Detecting the Earliest Galaxies Through Two New Sources of 21cm Fluctuations
• Escape of Ionizing Radiation from High Redshift Galaxies
• Reionization of Hydrogen and Helium by Early Stars and Quasars
• Photoionization Feedback in Low--Mass Galaxies at High Redshift
• A Method for Separating the Physics from the Astrophysics of High-Redshift 21cm Fluctuations
• Radio Signatures of HI at High Redshift: Mapping the End of the ``Dark Ages''
• Fossil HII Regions: Self-Limiting Star Formation at High Redshift
• The Evolution of Optical Depth in the Ly-alpha Forest: Evidence Against Reionization at z~6
• Taxing the Rich: Recombinations and Bubble Growth During Reionization
• Radio Foregrounds for the 21cm Tomography of the Neutral Intergalactic Medium at High Redshifts
• Statistical Probes of Reionization With 21 cm Tomography
• A Survey of z~6 Quasars in the SDSS Deep Stripe: I. a Flux-Limited Sample at z_{AB}<21
• Baryonic Acoustic Oscillations in 21cm Emission: A Probe of Dark Energy out to High Redshifts
• The nature and evolution of the highly ionized near-zones in the absorption spectra of z~6 quasars
• A Uniform Analysis of the Ly-alpha forest at z = 0 - 5: II. Measuring the mean intensity of the extragalactic ionizing background using the proximity effect
• Cosmic Hydrogen Was Significantly Neutral a Billion Years After the Big Bang
• Redshifted 21 cm Emission From the Pre-Reionization Era I. Mean Signal and Linear Fluctuations
• Foregrounds for 21cm Observations of Neutral Gas at High Redshift
• Quasar Proximity Zones and Patchy Reionization
• A New Constraint on the Escape Fraction in Distant Galaxies Using Gamma-ray Burst Afterglow Spectroscopy
• Cosmic Reionization Redux
• Fluctuations in 21cm Emission After Reionization
• Improved Constraints on The Neutral Intergalactic Hydrogen Surrounding Quasars at Redshifts z>6
• The Impact of a Percolating IGM on Redshifted 21 cm Observations of Quasar HII Regions
• Probing the Epoch of Early Baryonic Infall Through 21cm Fluctuations
• Distribution of Damped Lyman-alpha Absorbers in a Lambda Cold Dark Matter Universe
• The SDSS-DR5 Survey for Proximate Damped Lya Systems
• Prospects for Redshifted 21-cm observations of quasar HII regions
• Redshifted 21cm Signatures Around the Highest Redshift Quasars
• Probing the Reionization History Using the Spectra of High-Redshift Sources
• Detecting ionized bubbles in redshifted 21 cm maps
• A closer look at using quasar near-zones as a probe of neutral hydrogen in the intergalactic medium
• Constraining the Quasar Contribution to the Reionisation of Cosmic Hydrogen
• Are There Enough Ionizing Photons to Reionize the Universe by z=6?
• Redshifted 21 cm Emission From the Pre-Reionization Era II. HII Regions Around Individual Quasars
• Properties of High Redshift Quasars-I: Evolution of the super-massive black-hole to halo mass ratio

Cited by in corpus (5)

• Science with the Murchison Widefield Array
• Probabilistic selection of high-redshift quasars
• Simulating the impact of HI fluctuations on matched filter search for ionized bubbles in redshifted 21 cm maps
• Probing quasar lifetimes with proximate $21$-centimetre absorption in the diffuse intergalactic medium at redshifts $z\ge 6$
• Probing Cosmological Reionization through Radio-interferometric Observations of Neutral Hydrogen