Radiative processes in the intracluster plasma

Itoh, Naoki; Sakamoto, T.; Kusano, Shugo; Kawana, Youhei; Nozawa, Satoshi

doi:10.1051/0004-6361:20011664

Cited by 23 publications

(21 citation statements)

References 49 publications

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“…We use the astrophysical plasma emission database (APED) which includes thermal bremsstrahlung, radiative recombination, line emission, and two-photon emission (Smith et al 2001). In addition, we apply corrections for galactic absorption (Morrison & McCammon 1983), relativistic effects (Itoh et al 2000), and electron-electron bremsstrahlung (Itoh et al 2002), to obtain the X-ray emissivity ( ν ) as a function of frequency ν.…”

Section: Application Of Cluster Models To X-ray Datamentioning

confidence: 99%

The effect of helium sedimentation on galaxy cluster masses and scaling relations

Bulbul

Hasler

Bonamente

et al. 2011

A&A

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Context. Recent theoretical studies predict that the inner regions of galaxy clusters may have an enhanced helium abundance due to sedimentation over the cluster lifetime. If sedimentation is not suppressed (e.g., by tangled magnetic fields), this may significantly affect the cluster mass estimates. Aims. We use Chandra X-ray observations of eight relaxed galaxy clusters to investigate the upper limits to the effect of helium sedimentation on the measurement of cluster masses and the best-fit slopes of the Y X − M 500 and Y X − M 2500 scaling relations. Methods. We calculated gas mass and total mass in two limiting cases: a uniform, unenhanced abundance distribution and a radial distribution from numerical simulations of helium sedimentation on a timescale of 11 Gyr. Results. The assumed helium sedimentation model, on average, produces a negligible increase in the gas mass inferred within large radii (r < r 500 ) (1.3 ± 1.2%) and a 10.2 ± 5.5% mean decrease in the total mass inferred within r < r 500 . Significantly stronger effects in the gas mass (10.5 ± 0.8%) and total mass (25.1 ± 1.1%) are seen at small radii owing to a larger variance in helium abundance in the inner region, r ≤ 0.1 r 500 . Conclusions. We find that the slope of the Y X − M 500 scaling relation is not significantly affected by helium sedimentation.

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Section: Application Of Cluster Models To X-ray Datamentioning

confidence: 99%

The effect of helium sedimentation on galaxy cluster masses and scaling relations

Bulbul

Hasler

Bonamente

et al. 2011

A&A

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“…So, the results of Itoh et al (1998) can be regarded as exact in the framework of the single scattering approximation. Analytical fitting formulae of such derivation can be found in Nozawa et al (2000) and Itoh et al (2002). Such a formalism seems to offer a detailed description of the thermal SZ effect for k B T e ∼ < 15 keV, while Monte Carlo simulations describe more correctly the thermal SZ effect even for k B T e ∼ > 20 keV (see, e.g., Challinor & Lasenby 1998).…”

Section: Introductionmentioning

confidence: 99%

The non-thermal Sunyaev–Zel'dovich effect in clusters of galaxies

Colafrancesco

Marchegiani

Palladino

2002

A&A

102

250

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Abstract. In this paper we provide a general derivation of the non-thermal Sunyaev-Zel'dovich (SZ) effect in galaxy clusters which is exact in the Thomson limit to any approximation order in the optical depth τ. The general approach we use also allows us to obtain an exact derivation of the thermal SZ effect in a self-consistent framework. Such a general derivation is obtained using the full relativistic formalism and overcoming the limitations of the Kompaneets and of the single scattering approximations. We compare our exact results with those obtained at different approximation orders in τ and we give estimates of the precision fit. We verified that the third order approximation yields a quite good description of the spectral distortion induced by the Comptonization of CMB photons in the cluster atmosphere. In our general derivation, we show that the spectral shape of the thermal and non-thermal SZ effect depends not only on the frequency but also on the cluster parameters, like the electron pressure and optical depth and from the energy spectrum of the electron population. We also show that the spatial distribution of the thermal and non-thermal SZ effect in clusters depends on a combination of the cluster parameters and on the spectral features of the effect. To have a consistent description of the SZ effect in clusters containing non-thermal phenomena, we also evaluate in a consistent way -for the first time -the total SZ effect produced by a combination of thermal and nonthermal electron population residing in the same environment, like is the case in radio-halo clusters. In this context, we show that the location of the zero of the total SZ effect increases non-linearly with increasing values of the pressure ratio between the non-thermal and thermal electron populations and its determination provides a unique way to determine the pressure of the relativistic particles residing in the cluster atmosphere. We discuss in detail both the spectral and the spatial features of the total (thermal plus non-thermal) SZ effect and we provide specific predictions for a well studied radio-halo cluster like A2163. Our general derivation allows also to discuss the overall SZ effect produced by a combination of different thermal populations residing in the cluster atmosphere. Such a general derivation of the SZ effect allows to consider also the CMB Comptonization induced by several electron populations. In this context, we discuss how the combined observations of the thermal and non-thermal SZ effect and of the other non-thermal emission features occurring in clusters (radio-halo, hard X-ray and EUV excesses) provide relevant constraints of the spectrum of the relativistic electron population and, in turn, on the presence and on the origin of non-thermal phenomena in galaxy clusters. We finally discuss how SZ experiments with high sensitivity and narrow-band spectral coverage, beyond the coming PLANCK satellite, can definitely probe the presence of a non-thermal SZ effect in galaxy clusters and disentangle this source o...

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“…They presented an accurate analyic fitting formula that has a high accuracy for the ranges 0.00 ≤ θ e ≤ 0.05 and 0 ≤ X ≤ 20, where θ e ≡ k B T e /m e c 2 , X ≡ ω/k B T 0 . Another fitting formula with a still higher precision that is valid for the more limited ranges 0.00 ≤ θ e ≤ 0.035, 0 ≤ X ≤ 15 was developed (Itoh et al 2002b). Relativistic corrections to the double scattering effect on the Sunyaev-Zeldovich effect was calculated by Itoh et al (2001).…”

Section: Introductionmentioning

confidence: 99%

Relativistic corrections to the Sunyaev-Zeldovich effect for extremely hot clusters of galaxies

Itoh

Nozawa²

2004

A&A

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Abstract. We present an accurate numerical table for the relativistic corrections to the thermal Sunyaev-Zeldovich effect for clusters of galaxies. The numerical results for the relativistic corrections have been obtained by numerical integration of the collision term of the Boltzmann equation. The numerical table is provided for the ranges 0.002 ≤ θ e ≤ 0.100 and 0 ≤ X ≤ 20, where θ e ≡ k B T e /m e c 2 , X ≡ ω/k B T 0 , T e is the electron temperature, ω is the angular frequency of the photon and T 0 is the temperature of the cosmic microwave background radiation. We also present an accurate analytic fitting formula that reproduces the numerical results with high precision.

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Radiative processes in the intracluster plasma

Cited by 23 publications

References 49 publications

The effect of helium sedimentation on galaxy cluster masses and scaling relations

The effect of helium sedimentation on galaxy cluster masses and scaling relations

The non-thermal Sunyaev–Zel'dovich effect in clusters of galaxies

Relativistic corrections to the Sunyaev-Zeldovich effect for extremely hot clusters of galaxies

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