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Title: Quasar H II Regions During Cosmic Reionization

Abstract

Cosmic reionization progresses as HII regions form around sources of ionizing radiation. Their average size grows continuously until they percolate and complete reionization. We demonstrate how this typical growth can be calculated around the largest, biased sources of UV emission such as quasars by further developing an analytical model based on the excursion set formalism. This approach allows us to calculate the sizes and growth of the HII regions created by the progenitors of any dark matter halo of given mass and redshift with a minimum of free parameters. Statistical variations in the size of these pre-existing HII regions are an additional source of uncertainty in the determination of very high redshift quasar properties from their observed HII region sizes. We use this model to demonstrate that the transmission gaps seen in very high redshift quasars can be understood from the radiation of only their progenitors and associated clustered small galaxies. The fit requires the epoch of overlap to be at z = 5.8 {+-} 0.1. This interpretation makes the transmission gaps independent of the age of the quasars observed. If this interpretation were correct it would raise the prospects of using radio interferometers currently under construction to detect themore » epoch of reionization.« less

Authors:
; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
901574
Report Number(s):
SLAC-PUB-12429
astro-ph/0703740; TRN: US200714%%109
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Submitted to Mon.Not.Roy.Astron.Soc.
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONSTRUCTION; GALAXIES; INTERFEROMETERS; IONIZING RADIATIONS; NONLUMINOUS MATTER; QUASARS; RADIATIONS; Astrophysics,ASTRO

Citation Formats

Alvarez, Marcelo A., Abel, Tom, and /KIPAC, Menlo Park. Quasar H II Regions During Cosmic Reionization. United States: N. p., 2007. Web. doi:10.1111/j.1745-3933.2007.00342.x.
Alvarez, Marcelo A., Abel, Tom, & /KIPAC, Menlo Park. Quasar H II Regions During Cosmic Reionization. United States. doi:10.1111/j.1745-3933.2007.00342.x.
Alvarez, Marcelo A., Abel, Tom, and /KIPAC, Menlo Park. Fri . "Quasar H II Regions During Cosmic Reionization". United States. doi:10.1111/j.1745-3933.2007.00342.x. https://www.osti.gov/servlets/purl/901574.
@article{osti_901574,
title = {Quasar H II Regions During Cosmic Reionization},
author = {Alvarez, Marcelo A. and Abel, Tom and /KIPAC, Menlo Park},
abstractNote = {Cosmic reionization progresses as HII regions form around sources of ionizing radiation. Their average size grows continuously until they percolate and complete reionization. We demonstrate how this typical growth can be calculated around the largest, biased sources of UV emission such as quasars by further developing an analytical model based on the excursion set formalism. This approach allows us to calculate the sizes and growth of the HII regions created by the progenitors of any dark matter halo of given mass and redshift with a minimum of free parameters. Statistical variations in the size of these pre-existing HII regions are an additional source of uncertainty in the determination of very high redshift quasar properties from their observed HII region sizes. We use this model to demonstrate that the transmission gaps seen in very high redshift quasars can be understood from the radiation of only their progenitors and associated clustered small galaxies. The fit requires the epoch of overlap to be at z = 5.8 {+-} 0.1. This interpretation makes the transmission gaps independent of the age of the quasars observed. If this interpretation were correct it would raise the prospects of using radio interferometers currently under construction to detect the epoch of reionization.},
doi = {10.1111/j.1745-3933.2007.00342.x},
journal = {Submitted to Mon.Not.Roy.Astron.Soc.},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 30 00:00:00 EDT 2007},
month = {Fri Mar 30 00:00:00 EDT 2007}
}
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  • We have imaged CO(J = 7 -> 6) and C I({sup 3} P {sub 2} -> {sup 3} P {sub 1}) emission in the host galaxy of the z = 6.42 quasar SDSS J114816.64+525150.3 (hereafter J1148+5251) through observations with the Plateau de Bure Interferometer. The region showing CO(J = 7 -> 6) emission is spatially resolved, and its size of 5 kpc is in good agreement with earlier CO(J = 3 -> 2) observations. In combination with a revised model of the collisional line excitation in this source, this indicates that the highly excited molecular gas traced by the COmore » J = 7 -> 6 line is subthermally excited (showing only 58% +- 8% of the CO J = 3 -> 2 luminosity), but not more centrally concentrated. We also detect C I({sup 3} P {sub 2} -> {sup 3} P {sub 1}) emission in the host galaxy of J1148+5251, but the line is too faint to enable a reliable size measurement. From the C I({sup 3} P {sub 2} -> {sup 3} P {sub 1}) line flux, we derive a total atomic carbon mass of M{sub CI} = 1.1 x10{sup 7} M {sub sun}, which corresponds to approx5 x 10{sup -4} times the total molecular gas mass. We also searched for H{sub 2}O(J{sub K{sub aK{sub c}}} = 2{sub 12} -> 1{sub 01}) emission, and obtained a sensitive line luminosity limit of L{sup '}{sub H{sub 2O}}< 4.4 x 10{sup 9} K km s{sup -1} pc{sup 2}, i.e., <15% of the CO(J = 3 -> 2) luminosity. The warm, highly excited molecular gas, atomic gas and dust in this quasar host at the end of cosmic reionization maintain an intense starburst that reaches surface densities as high as predicted by (dust opacity) Eddington limited star formation over kiloparsec scales.« less
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