Relativistic Compton Energy Exchange

Corman, E.G.

doi:10.1103/physrevd.1.2734

Cited by 10 publications

(4 citation statements)

References 3 publications

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“…The asymptotic nature of the expansion of ∂n/∂t in θ e requires the inclusion of higher-order corrections to calculate the effect in hotter clusters in the Wien region of the spectrum. While the calculation of higher-order corrections is not problematic, the bad convergence properties of the series means that ultimately one must resort to a numerical calculation of the collision integral (Corman 1970) (or employ the multiple scattering formalism (Wright 1979)) to calculate the effect in very hot clusters.…”

Section: Resultsmentioning

confidence: 99%

Relativistic Corrections to the Sunyaev‐Zeldovich Effect

Challinor¹,

Lasenby²

1998

ApJ

225

247

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We present an extension of the Kompaneets equation which allows relativistic effects to be included to any desired order. Using this, we are able to obtain simple analytic forms for the spectral changes due to the Sunyaev-Zel'dovich effect in hot clusters, correct to first and second order in the expansion parameter θ e = k B T e /mc 2. These analytic forms agree with previous numerical calculations of the effect based upon the multiple scattering formalism, and are expected to be very accurate over all regions of the CMB spectrum for k B T e up to ∼ 10 keV. Our results confirm previous conclusions that the result of including relativistic corrections in the Sunyaev-Zel'dovich effect is a small reduction in the amplitude of the effect over the majority of the spectrum: specifically we find ∆T/T = −2y(1 − 17/10 θ e + 123/40 θ 2 e) (correct to second-order) in the Rayleigh-Jeans region, where y is the usual Comptonization parameter. For a typical cluster temperature of 8 keV, this amounts to a correction downwards to the value of the Hubble constant derived using combined X-ray and Rayleigh-Jeans Sunyaev-Zel'dovich information by about 5 percent.

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Section: Resultsmentioning

confidence: 99%

Relativistic Corrections to the Sunyaev‐Zeldovich Effect

Challinor¹,

Lasenby²

1998

ApJ

225

247

View full text Add to dashboard Cite

show abstract

“…The asymptotic nature of the series expansion of ∂n/∂t in θ e requires the inclusion of higher-order corrections to calculate the effect in hotter clusters in the Wien region of the spectrum. While the calculation of higher-order corrections is not problematic, the bad convergence properties of the series means that ultimately one must resort to a numerical calculation of the collision integral [21,22] (or employ the multiple scattering formalism [9]) to calculate the distortion in very hot clusters.…”

Section: Resultsmentioning

confidence: 99%

Recent Developments in the Calculation of CMB Anisotropies

Challinor

Lasenby

1998

Current Topics in Astrofundamental Physics: Primordial Cosmology

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We discuss three recent developments in the calculation of Cosmic Microwave Background (CMB) anisotropies. We begin with a discussion of the relativistic corrections to the Sunyaev-Zel'dovich effect. By extending the Kompaneets equation to include relativistic effects, we are able to to derive simple analytic forms for the spectral changes due to the thermal Sunyaev-Zel'dovich effect. Relativistic corrections result in a small reduction in the amplitude of the effect over the Rayleigh-Jeans region, which for a typical cluster temperature of 8 keV, amounts to a correction downwards to the value of the Hubble constant derived from combined X-ray and Sunyaev-Zel'dovich information by about 5 percent. Our second topic is a discussion of covariant kinetic theory methods for the gauge-invariant calculation of primordial CMB anisotropies. We present a covariant version of the Boltzmann equation, which we use to derive a set of covariant equations for the gauge-invariant variables in a Cold Dark Matter (CDM) model, which are independent of the background curvature and type of perturbation. Equations describing a particular type of perturbation are obtained readily from this set, as we demonstrate for scalar perturbations in a K = 0 universe. By integrating the covariant Boltzmann equations along the line of sight, and using the instantaneous recombination approximation, we obtain an expression for the large scale anisotropy which agrees with an expression derived recently by Dunsby. Finally, we discuss some recent accurate calculations of the CMB anisotropy in global defect models. In such models, the effect of vorticity generation by the causal sources proves to be significant, leading to a suppression of acoustic peaks. The result is that global defect models of structure formation may already be at variance with the growing volume of CMB (and large scale structure) data.

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“…The calculation method used here is mainly based on that in Pozdniakov, Sobol, & Siuniaev (1977) and Gorecki & Wilczewski (1984), but their original formalism in the laboratory frame is not optimized for the ultra-relativistic region. To calculate the scattering by high energy nonthermal electrons more efficiently, we added a new formulation in the rest frame of relativistic electrons based on Corman (1970).…”

Section: Model Descriptionmentioning

confidence: 99%

The Cosmic MeV Gamma-Ray Background and Hard X-Ray Spectra of Active Galactic Nuclei: Implications for the Origin of Hot AGN Coronae

Inoue

Totani

Ueda

2007

ApJ

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The origin of the extragalactic gamma-ray background radiation at 1-10 MeV is still unknown. Although the cosmic X-ray background (CXB) up to a few hundreds keV can be accounted for by the sum of Active Galactic Nuclei (AGNs), current models of AGN spectra cannot explain the background spectrum beyond ∼1 MeV, because of the thermal exponential cutoff of electron energy distribution assumed in the models. Here we construct a new spectral model by calculating the Comptonization process including nonthermal electrons, which are expected to exist in an AGN hot corona if it is heated by magnetic reconnections. We show that the MeV background spectrum can nicely be explained by our model, when coronal electrons have a nonthermal power-law component whose total energy is a few percent of the thermal component and whose spectral index is d ln N e /d ln E e ≈ −4. Although the MeV gamma-ray flux from such a component in nearby AGN spectra is below the detection limit of past observations, it could be detected by planned future MeV detectors. We point out that the amount of the nonthermal component and its electron index are similar to those found for electrons accelerated by magnetic reconnections in solar flares and the Earth magnetosphere, giving a support to the reconnection hypothesis for the origin of hot AGN coronae.

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Relativistic Compton Energy Exchange

Cited by 10 publications

References 3 publications

Relativistic Corrections to the Sunyaev‐Zeldovich Effect

Relativistic Corrections to the Sunyaev‐Zeldovich Effect

Recent Developments in the Calculation of CMB Anisotropies

The Cosmic MeV Gamma-Ray Background and Hard X-Ray Spectra of Active Galactic Nuclei: Implications for the Origin of Hot AGN Coronae

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