Cosmic microwave background constraints on the epoch of reionization

Griffiths, Louise M.; Barbosa, Domingos; Liddle, Andrew R.

doi:10.1046/j.1365-8711.1999.02777.x

Cited by 36 publications

(40 citation statements)

References 74 publications

(79 reference statements)

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“…For a fully ionized universe, contributions are moderately dependent on the optical depth τ . Here, we assume an optical depth to ionization of 0.05, consistent with current upper limits on the reionization redshift from CMB [95] and other observational data (see, e.g., [100] and references therein). In figure 59, we have calculated the kinetic SZ power spectrum under several assumptions, including the case when gas is assumed to trace the non-linear density field and the linear density field.…”

Section: Kinetic Sz Power Spectrummentioning

confidence: 77%

Halo models of large scale structure

2002

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We review the formalism and applications of the halo-based description of nonlinear gravitational clustering. In this approach, all mass is associated with virialized dark matter halos; models of the number and spatial distribution of the halos, and the distribution of dark matter within each halo, are used to provide estimates of how the statistical properties of large scale density and velocity fields evolve as a result of nonlinear gravitational clustering. We first describe the model, and demonstrate its accuracy by comparing its predictions with exact results from numerical simulations of nonlinear gravitational clustering. We then present several astrophysical applications of the halo model: these include models of the spatial distribution of galaxies, the nonlinear velocity, momentum and pressure fields, descriptions of weak gravitational lensing, and estimates of secondary contributions to temperature fluctuations in the cosmic microwave background.

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Section: Kinetic Sz Power Spectrummentioning

confidence: 77%

Halo models of large scale structure

2002

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“…Table 1 describes the corresponding gridding used for the database. The models including reionization have been computed with an analytical approximation (Griffiths et al 1999).…”

Section: Model Grid and Likelihood Methodsmentioning

confidence: 99%

Cosmological constraints from Archeops

Benoı̂t¹,

Ade²,

Amblard³

et al. 2003

A&A

202

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Abstract. We analyze the cosmological constraints that Archeops (Benoît et al. 2003) places on adiabatic cold dark matter models with passive power-law initial fluctuations. Because its angular power spectrum has small bins in and large coverage down to COBE scales, Archeops provides a precise determination of the first acoustic peak in terms of position at multipole l peak = 220 ± 6, height and width. An analysis of Archeops data in combination with other CMB datasets constrains the baryon content of the Universe, Ω b h 2 = 0.022−0.004 , compatible with Big-Bang nucleosynthesis and with a similar accuracy. Using cosmological priors obtained from recent non-CMB data leads to yet tighter constraints on the total density, e.g. Ω tot = 1.00 +0.03 −0.02 using the HST determination of the Hubble constant. An excellent absolute calibration consistency is found between Archeops and other CMB experiments, as well as with the previously quoted best fit model. The spectral index n is measured to be 1.04 +0.10 −0.12 when the optical depth to reionization, τ, is allowed to vary as a free parameter, and 0.96 +0.03 −0.04 when τ is fixed to zero, both in good agreement with inflation.Key words. cosmic microwave background -cosmological parameters -early Universe -large-scale structure of the Universe Send offprint requests to: A. Benoît,

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“…The universe is likely to have been reionized in the period where the lower bound arises from the 5.8 \ z r \ 35, lack of Gunn-Peterson absorption in the spectra of highredshift quasars (Fan et al 2000), and the upper bound comes from the observation of small-scale power in cosmic microwave background (CMB) anistropies (Griffiths, Barbosa, & Liddle 1999). In cold dark matter (CDM) cosmologies, nonlinear objects above the cosmological Jeans mass 104È105…”

Section: Introductionmentioning

confidence: 99%

Reionization by Hard Photons. I. X‐Rays from the First Star Clusters

2001

ApJ

191

244

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Observations of the Lya forest at z D 3 reveal an average metallicity Z D 10~2The high-redshift Z _ . supernovae that polluted the intergalactic medium also accelerated relativistic electrons. Since the energy density of the cosmic microwave background is proportional to (1 ] z)4, at high redshift these electrons cool via inverse Compton scattering. Thus, the Ðrst star clusters emit X-rays. Unlike stellar UV ionizing photons, these X-rays can escape easily from their host galaxies. This has a number of important physical consequences :1. Owing to their large mean free path, these X-rays can quickly establish a universal ionizing background and partially reionize the universe in a gradual, homogeneous fashion. If X-rays formed the dominant ionizing background, the universe would have more closely resembled a single-phase medium rather than a two-phase medium.2. X-rays can reheat the universe to higher temperatures than possible with UV radiation. 3. X-rays counter the tendency of UV radiation to photodissociate an important coolant in the H 2 , early universe, by promoting gas-phase formation. H 2The X-ray production efficiency is calibrated to local observations of starburst galaxies, which imply that D10% of the supernova energy is converted to X-rays. While direct detection of sources in X-ray emission is difficult, the presence of relativistic electrons at high redshift and thus a minimal level of X-ray emission may be inferred by synchrotron emission observations with the Square Kilometer Array. These sources may constitute a signiÐcant fraction of the unresolved hard X-ray background and can account for both the shape and amplitude of the gamma-ray background. This paper discusses the existence and observability of high-redshift X-ray sources, while a companion paper models the detailed reionization physics and chemistry.

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Cosmic microwave background constraints on the epoch of reionization

Cited by 36 publications

References 74 publications

Halo models of large scale structure

Halo models of large scale structure

Cosmological constraints from Archeops

Reionization by Hard Photons. I. X‐Rays from the First Star Clusters

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