TY - JOUR

T1 - CMB Comptonization in clusters

T2 - Spectral and angular power from evolving polytropic gas

AU - Sadeh, Sharon

AU - Rephaeli, Yoel

N1 - Funding Information:
This research has been supported by the Israeli Science Foundation grant 729⧹00-03 at Tel-Aviv University.

PY - 2004/2

Y1 - 2004/2

N2 - The angular power spectrum of the Sunyaev-Zeldovich (SZ) effect is calculated in the ΛCDM cosmological model with the aim of investigating its detailed dependence on the cluster population, gas morphology, and gas evolution. We calculate the power spectrum for three different mass functions, compute it within the framework of isothermal and polytropic gas distributions, and explore the effect of gas evolution on the magnitude and shape of the power spectrum. We show that it is indeed possible to explain the 'excess' power measured by the CBI experiment on small angular scales as originating from the SZ effect without (arbitrary) rescaling the value of σ8, the mass variance parameter. The need for a self-consistent choice of the basic parameters characterizing the cluster population is emphasized. In particular, we stress the need for a consistent choice of the value of σ8 extracted from fitting theoretical models for the mass function to the observed cluster X-ray temperature function, such that it agrees with the mass-temperature relation used to evaluate the cluster Comptonization parameter. Our treatment includes the explicit spectral dependence of the thermal component of the effect, which we calculate at various frequencies. We find appreciable differences between the nonrelativistic and relativistic predictions for the power spectrum even for this superposed contribution from clusters at the full range of gas temperatures.

AB - The angular power spectrum of the Sunyaev-Zeldovich (SZ) effect is calculated in the ΛCDM cosmological model with the aim of investigating its detailed dependence on the cluster population, gas morphology, and gas evolution. We calculate the power spectrum for three different mass functions, compute it within the framework of isothermal and polytropic gas distributions, and explore the effect of gas evolution on the magnitude and shape of the power spectrum. We show that it is indeed possible to explain the 'excess' power measured by the CBI experiment on small angular scales as originating from the SZ effect without (arbitrary) rescaling the value of σ8, the mass variance parameter. The need for a self-consistent choice of the basic parameters characterizing the cluster population is emphasized. In particular, we stress the need for a consistent choice of the value of σ8 extracted from fitting theoretical models for the mass function to the observed cluster X-ray temperature function, such that it agrees with the mass-temperature relation used to evaluate the cluster Comptonization parameter. Our treatment includes the explicit spectral dependence of the thermal component of the effect, which we calculate at various frequencies. We find appreciable differences between the nonrelativistic and relativistic predictions for the power spectrum even for this superposed contribution from clusters at the full range of gas temperatures.

KW - Cosmic microwave background

KW - Cosmology: miscellaneous

KW - Galaxies: clusters: general

UR - http://www.scopus.com/inward/record.url?scp=0242271248&partnerID=8YFLogxK

U2 - 10.1016/j.newast.2003.09.001

DO - 10.1016/j.newast.2003.09.001

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AN - SCOPUS:0242271248

SN - 1384-1076

VL - 9

SP - 159

EP - 171

JO - New Astronomy

JF - New Astronomy

IS - 2

ER -