The S-Z effect and Faraday rotation from halos are examined over a wide mass range, an including gas condensation and magnetic field evolution. Contributions to the CMB angular power spectrum are evaluated for galaxy clusters, galaxy groups and galaxies. Smaller mass halos are found to play a more important role than massive halos for the B-mode polarisation associated with the S-Z CMB anisotropies. The B-modes from Faraday rotation dominate the secondary B-modes caused by gravitational lensing at l > 3000. Measurement of B-mode polarisation in combination with the S-Z power spectrum can potentially provide important constraints on intracluster magnetic field and gas evolution at early epochs.
We describe a fast method to simulate in a semi-analytical way consistent maps of the thermal, kinetic and polarised Sunyaev-Zel'dovich effect, featuring both cluster spatial correlations and large scale velocity flows.
The Sunyaev-Zel'dovich effect causes a change in the apparent brightness of the Cosmic Microwave Background Radiation towards a cluster of galaxies or any other reservoir of hot plasma. Measurements of the effect provide distinctly different information about cluster properties than X-ray imaging data, while combining X-ray and Sunyaev-Zel'dovich effect data leads to new insights into the structures of cluster atmospheres. The effect is redshift-independent, and so provides a unique probe of the structure of the Universe on the largest scales. The present review discusses the theory of the Sun…
This review discusses the techniques used in single-dish and interferometric radiometric observations of the Sunyaev-Zel'dovich effects, the pitfalls that arise, the systematic and other sources of error in the data, and the uncertainties in the interpretation of the results.
The thermal Sunyaev-Zel'dovich effect is an important probe of clusters of galaxies, and has the attractive property of being proportional to the thermal energy content of the intracluster medium. With the assistance of X-ray data, the effect can be used to measure the number of hot electrons in clusters, and thus measure cluster baryon contents. Cluster absolute distances and other structural parameters can also be measured by combining thermal Sunyaev-Zel'dovich, X-ray, and other data. This review presents an introduction to the effect, shows some representative results, and sketches imminen…
Our three frequencies radiometer MASTER which allows low noise observations in three frequency intervals around 90, 220 and 345 GHz is being completed. We discuss the possibility of exploiting the MASTER`s charachteristics for studies of the Sunyaev Zel`dovich effect from the Antarctic Plateau and propose an observational program from Dome C
Sunyaev Zel'dovich cluster surveys can be used to constrain cosmological parameters. Extracting clusters from the primary anisotropies and the unresolved background from very faint clusters is simple when the telescope beam size is small (1 arcmin), but could be difficult if the beam is larger (8 arcmin). By reference to examples, we show that this is possible by carefully designing the depth of the survey.
The well known Sunyaev-Zel'dovich (SZ) effect is reexamined using a Doppler shift type mechanism arising from the scattering of photons by electrons in an optically thin gas. The results are in excellent agreement with the observational data as well as with the results obtained using the diffusive pictures. A comparison of the results here obtained with other approaches is thoroughly discussed, as well as some important extensions of this method to other aspects of the SZ effect
Analytical expressions for the non-relativistic and relativistic Sunyaev-Zel'dovich effect (SZE) are derived by means of suitable convolution integrals. The establishment of these expressions is based on the fact that the SZE disturbed spectrum, at high frequencies, possesses the form of a Laplace transform of the single line distortion profile (structure factor). Implications of this description of the SZE related to light scattering in optically thin plasmas are discussed.
Among various analytic approximations for the growth of density fluctuations in the expanding Universe, Zel'dovich approximation and its extensions in Lagrangian scheme are known to be accurate even in mildly non-linear regime. The aim of this paper is to investigate the reason why these Zel'dovich-type approximations work accurately beyond the linear regime from the following two points of view: (1) Dimensionality of the system and (2) the Lagrangian scheme on which the Zel'dovich approximation is grounded. In order to examine the dimensionality, we introduce a model with spheroidal mass dist…
We extend the formalism of the relativistic thermal Sunyaev-Zel'dovich effect to the system moving with a velocity beta (= v/c) with respect to the cosmic microwave background radiation. In the present formalism, the kinematic Sunyaev-Zel'dovich effect for the cluster of galaxies with a peculiar velocity is derived in a straightforward manner by the Lorentz boost of the generalized Kompaneets equation. We give an analytic expression for the kinematic Sunyaev-Zel'dovich effect which is valid up to O(beta^{2}) with the power series expansion approximation in terms of theta_{e} = k_{B} T_{e}/ mc^…
We extend the formalism of the relativistic thermal and kinematic Sunyaev-Zel'dovich effects and include the polarization of the cosmic microwave background photons. We consider the situation that a cluster of galaxies is moving with a velocity \vec{v} with respect to the cosmic microwave background radiation. In the present formalism, polarization of the scattered cosmic microwave background radiation caused by the proper motion of a cluster of galaxies is naturally derived as a special case of the kinematic Sunyaev-Zel'dovich effect. The relativistic corrections are included also in a natura…
We review recent results of Sunyaev-Zel'dovich effect (SZE) observations toward galaxy clusters. Using cm-wave receivers mounted on the OVRO and BIMA mm-wave arrays we have obtained high signal to noise images of the effect for more than 20 clusters. We present current estimates of the Hubble constant and cosmological parameters and discuss the potential of conducting statistical studies with large SZE cluster samples.
We are engaged in a program with the Cosmic Background Imager (CBI), a 13-element interferometer recently installed at 5000 m in the Chilean Andes, to measure H_0 with 10% accuracy through observations of the Sunyaev-Zel'dovich effect in a sample of nearby clusters. We discuss the capabilities of this new instrument and present our cluster sample and selection criteria, along with results from detailed simulations. We also present preliminary observations of Abell 478.
Compton scattering of Cosmic Microwave Background (CMB) photons on galaxy cluster electrons produces a linear polarization, which contains some information on the local quadrupole at the cluster location. We use N-body simulations to create, for the first time, maps of this polarization signal. We then look at the different properties of the polarization with respect to the cluster position and redshift.
Analytical expressions are presented for relativistic corrections to the Kompaneets equation and the Sunyaev-Zel'dovich y-distortion. The latter provides a convenient method of inferring both the temperature and Thomson optical depth of the gas in clusters of galaxies using only observations of the spectrum of CMBR photons passing through the cluster. The relativistic correction gives an additional component of the S-Z effect apart from the y-distortion and kinematic S-Z effect. The perturbative method used is shown to provide a very accurate approximations when kTe~<100keV but not for higher …
We investigate the influence of the finite extension and the aspherical geometry of a galaxy cluster on the estimate of the Hubble constant through the Sunyaev-Zel'dovich effect. An analysis of a recent CHANDRA image of the galaxy cluster RBS797 indicates a strong ellipticity and thus a pronounced aspherical geometry. We estimate the total mass of RBS797 assuming spherical or ellipsoidal geometry and show that in the latter case the mass is about 10-17 % less than the one inferred for a spherical shape.
Evolution of genus density is calculated from Gaussian initial conditions using Zel'dovich approximation. A new approach is introduced which formulates the desired quantity in a rotationally invariant manner. It is shown that normalized genus density does not depend on the initial spectral shape but is a function of the fluctuation amplitude only.
In a previous publication we have derived an expression for the full distorted spectrum arising when the photons of the cosmic background radiation are absorbed and emitted by an optically thin gas. The expression simply adds up the effects of the joint probability that an electron absorbs an incoming photon of frequency}$\barν${\small and emits it with a frequency}$ν${\small . We here show that such an expression is identical to the Kompaneets equation describing the thermal Sunyaev-Zel'dovich effect. This clearly shows that the two pictures, diffusion and absorption-emission are mathematical…
The Hubble constant estimated from the combined analysis of the Sunyaev-Zel'dovich effect and X-ray observations of galaxy clusters is systematically lower than those from other methods by 10-15 percent. We examine the origin of the systematic underestimate using an analytic model of the intracluster medium (ICM), and compare the prediction with idealistic triaxial models and with clusters extracted from cosmological hydrodynamical simulations. We identify three important sources for the systematic errors; density and temperature inhomogeneities in the ICM, departures from isothermality, and a…
This study shows one important effect of preexistent cosmic microwave background temperature fluctuations on the determination of the Hubble constant through Sunyaev-Zel'dovich effect of clusters of galaxies, especially when coupled with the gravitational lensing effect by the same clusters. The effect results in a broad distribution of the apparent Hubble constant. The combination of this effect with other systematic effects such as the Loeb-Refregier Effect seems to provide an explanation for the observationally derived values of the Hubble constant currently available based on the Sunyaev-Z…
We investigate the performance of the optimized Post-Zel'dovich approximation in three cold dark matter cosmologies. We consider two flat models with $Ω_0=1$ (SCDM) and with $Ω_0=0.3$ ($Λ$CDM) and an open model with $Ω_0=0.3$ (OCDM). We find that the optimization scheme proposed by Weiß, Gottlöber & Buchert (1996), in which the performance of the Lagrangian perturbation theory was optimized only for the Einstein-de Sitter cosmology, shows the excellent performances not only for SCDM model but also for both OCDM and $Λ$CDM models. This universality of the excellent performance of the optimized …
We report on the first observation of the Sunyaev-Zel'dovich effect with the Diabolo experiment at the IRAM 30 metre telescope. A significant brightness decrement is detected in the direction of three clusters (Abell 665, Abell 2163 and CL0016+16). With a 30 arcsecond beam and 3 arcminute beamthrow, this is the highest angular resolution observation to date of the SZ effect.
We extend the formalism of the relativistic thermal and kinematical Sunyaev-Zeldovich effects to the observer's system (the Solar System) moving with a velocity $β_{S}$ with respect to the cosmic microwave background radiation. We confirm the results recently obtained by Chluba, Huetsi, and Sunyaev in the lowest order of the observer's velocity $β_{S}. We give a more general analytic expression for the thermal and kinematical Sunyaev-Zeldovich effects corresponding to the observer's system with the power series expansion approximation in terms of $θ_{e}$. It is found that the effect of the mot…
Among several analytic approximations for the growth of density fluctuations in the expanding Universe, Zel'dovich approximation in Lagrangian coordinate scheme is known to be unusually accurate even in mildly non-linear regime. This approximation is very similar to the Padé approximation in appearance. We first establish, however, that these two are actually different and independent approximations with each other by using a model of spheroidal mass collapse. Then we propose Padé-prescribed Zel'dovich-type approximations and demonstrate, within this model, that they are much accurate than any…
We study the influence of converging cooling flow bulk motions on the Sunyaev-Zel'dovich (SZ) effect. To that purpose we derive a modified Kompaneets equation which takes into account the contribution of the accelerated electron media of the cooling flow inside the cluster frame. The additional term is different from the usual kinematic SZ-effect, which depends linearly on the velocity, whereas the contribution described here is quadratic in the macroscopic electron fluid velocity, as measured in the cluster frame. For clusters with a large cooling flow mass deposition rate and/or a small cent…
The spectral distortion in the Cosmic Microwave Background Radiation (CMBR) caused from the inverse Compton scattering of low energy CMB photons by thermally distributed hot electrons in massive clusters of galaxies - better known as the thermal Sunyaev-Zel'dovich effect is usually estimated by the analytical or semi-analytical solutions of Kompaneets equation. These solutions are based on the assumption that the scattering is isotropic, i.e., the intensity of the CMBR remains angle-independent after scattering. In this letter, I present the solution of the full radiative transfer equations by…
We study the generalized Kompaneets equation (kinetic equation for the photon distribution function taking into account the Compton scattering by electrons) using a relativistically covariant formalism. Using the generalized Kompaneets equation, we derive an analytic expression for the Sunyaev-Zel'dovich effect, which takes into account up to O(theta**5) terms, where theta=kT/mc**2 is the relativistic expansion parameter and T is the electron temperature. We carefully study the applicable region of the obtained analytic expression by comparing with the result of the direct numerical integratio…
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 theta_e=k_B T_e/m c^2. These analytic forms agree with previous numerical calculations of the effect based upon the multiple scattering 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-Z…
The main issue in this paper is to discuss a parity property that appears in the expressions for the distorted spectrum of the thermal Sunyaev-Zel'dovich effect. When using the convolution integrals method involving scattering laws we argue that the distorted spectrum contains a new term, which is an odd power of the frequency. Such a term, absent in the conventional approaches, implies a crossover frequency which differs in value form the ones reported in the literature by a significant, in principle observable, amount. Also, such term casts doubt on the demanding need of computing complicate…
About 90% of baryons in the universe have thus far escaped direct observation. This is known as the {\it missing baryon problem}. The Sunyaev Zel'dovich effect (SZ effect) has the potential to directly measure the state of the majority of these missing baryons. The next generation CMB experiments such as AMIBA will provide an unbiased sample of the intergalactic medium through the SZ effect. The existing and upcoming simulations and analytical studies provide a quantitative understanding of the SZ effect. All these make the SZ effect a powerful baryon probe. We present an overview of this prob…
Upcoming surveys for galaxy clusters using the Sunyaev-Zel'dovich effect are potentially sensitive enough to create a peculiar velocity catalog. The statistics of these peculiar velocities are sensitive to cosmological parameters. We develop a method to explore parameter space using N-body simulations in order to quantify dark matter halo velocity statistics which will be useful for cluster peculiar velocity observations. We show that mass selection bias from a kinetic Sunyaev-Zel'dovich velocity catalog forecasts rms peculiar velocities with a much more complicated Omega_m dependency than sug…
In this paper we investigate the Sunyaev-Zel'dovich (SZ) effect and the X-ray surface brightness for clusters of galaxies with a non-spherical mass distribution. In particular, we consider the influence of the shape and the finite extension of a cluster as well as of a polytropic thermal profile on the Compton parameter, the X-ray surface brightness and on the determination of the Hubble constant. We find that the the non-inclusion of such effects can induce errors up to 30 per cent in the various parameters and in particular on the Hubble constant value, when compared with results obtained un…
We report on mapping observations toward the region of the most luminous X-ray cluster RXJ1347-1145 (z=0.45) through the Sunyaev-Zel'dovich effect at 21GHz and 150GHz with the Nobeyama 45-m telescope. While a low angular resolution image at 21GHz (beam-size of 76'') shows a consistent feature with the ROSAT/HRI X-ray image, a higher angular resolution image (13'') at 150GHz reveals complex morphological structures of the cluster region, which cannot be simply described by the spherical isothermal beta-model. If such inhomogeneous morphological features prove to be generic for high redshift clu…
We extend the formalism for the calculation of the relativistic corrections to the Sunyaev-Zel'dovich effect for clusters of galaxies and include the multiple scattering effects. We present a systematic method for the inclusion of the multiple scattering effects. The multiple scattering contribution is found to be very small compared with the single scattering contribution. For high-temperature galaxy clusters of k_{B}T_{e} = 15keV, the ratio of the both contributions is -0.3% in the Wien region. In the Rayleigh--Jeans region the ratio is -0.03%. Therefore the multiple scattering contribution …
We apply the coherency tensor formalism to the calculation of the spectral distortions imprinted in the intensity and polarization of the cosmic microwave background radiation due to the kinematic and thermal Sunyaev-Zeldovich effects (SZE). We obtain the first relativistic corrections to the intensity produced by the kinematic and thermal SZE, and the first correction to the polarization magnitude due to electron thermal motion.
The energy fed by active galactic nuclei to the surrounding diffuse baryons changes their amount, temperature, and distribution; so in groups and in member galaxies it affects the X-ray luminosity and also the Sunyaev-Zel'dovich effect. Here we compute how the latter is enhanced by the transient blastwave driven by an active quasar, and is depressed when the equilibrium is recovered with a depleted density. We constrain such depressions and enhancements with the masses of relic black holes in galaxies and the X-ray luminosities in groups. We discuss how all these linked observables can tell th…
The Ryle Telescope has been used to provide images at 15 GHz of the Sunyaev-Zel'dovich decrements towards a dozen clusters in an X-ray luminosity-limited sample. So far, X-ray data have allowed H_0 estimates towards two of these, both giving ``low'' values that are self-consistent, though it is essential to obtain many more estimates to reduce the effects of cluster projection. We have also discovered a decrement towards the z=3.8 quasar pair PC1643+4631A&B (198'' separation); substantial X-ray, optical and infrared follow-up show that the cluster responsible is either at z>1 or very underlumi…
We present an accurate analytic fitting formula for the numerical results for the relativistic corrections to the thermal Sunyaev-Zel'dovich 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 fitting is carried out for the ranges 0.02 < theta_{e} < 0.05 and 0 < X < 20, where theta_{e} = k_{B}T_{e}/m_{e}c^{2}, X = omega/k_{B}T_{0}, T_{e} is the electron temperature, omega is the angular frequency of the photon, and T_{0} is the temperature of the cosmic microwave…
Interferometric observations of the Sunyaev-Zel'dovich Effect (SZE) toward clusters of galaxies provide sensitive cosmological probes. We present results from 1 cm observations (at BIMA and OVRO) of a large, intermediate redshift cluster sample. In addition, we describe a proposed, higher sensitivity array which will enable us to survey large portions of the sky. Simulated observations indicate that we will be able to survey one square degree of sky per month to sufficient depth that we will detect all galaxy clusters more massive than 2x10^{14} h^{-1}_{50}M_\odot, regardless of their redshift…
We discuss how future cluster surveys can constrain cosmological parameters with particular reference to the properties of the dark energy component responsible for the observed acceleration of the universe by probing the evolution of the surface density of clusters as a function of redshift. We explain how the abundance of clusters selected using their Sunyaev-Zel'dovich effect can be computed as a function of the observed flux and redshift taking into account observational effects due to a finite beam-size. By constructing an idealized set of simulated observations for a fiducial model, we f…
We present a quantitative estimate of the confusion of cluster radio halos and galaxies in the measurement of the angular power spectrum of the thermal Sunyaev-Zel'dovich (SZ) effect. To achieve the goal, we use a purely analytic approach to both radio sources and dark matter of clusters by incorporating empirical models and observational facts together with some theoretical considerations. It is shown that the correction of cluster radio halos and galaxies to the measurement of the thermal SZ angular power spectrum is no more than 20% at $l>2000$ for observing frequencies $ν>30$ GHz. This eli…
We present a statistical strategy for the efficient determination of the cluster luminosity function from the Sunyaev-Zel'dovich (SZ) effects survey. To determine the cluster luminosity function from the noise contaminated SZ map, we first define the zeroth-order cluster luminosity function as a discrepancy between the measured peak number density of the SZ map and the mean number density of noise. Then we demonstrate that the noise contamination effects can be removed by the stabilized deconvolution of the zeroth-order cluster luminosity function with the one-dimensional Gaussian distribution…
We performed a systematic and comprehensive estimate of the Hubble constant $H_0$ via the Sunyaev-Zel'dovich temperature decrement and the X-ray measurements for clusters up to the redshift $z=0.541$, with particular attention to its dependence on the density parameter $Ω_0$, and the cosmological constant $λ_0$. The resulting values of $H_0$ are largely consistent with that derived from the Cepheid distance for nearby galaxies. We discuss how the angular diameter distance $d_A$ vs. $z$ diagram from the accurate SZ measurements of high-$z$ clusters can distinguish the values of $Ω_0$ and $λ_0$.
We examine the expected radio confusion on the thermal Sunyaev-Zel'dovich (SZ) effect of galaxy clusters at 28.5 GHz and 90 GHz based on the cluster radio luminosity function (CRLF) at 1.4 GHz. With the observationally determined spectral index ($α$, where $S_{\rmν}\proptoν^{-α}$) distribution, instead of a single average index $<α>$, we convert the cluster radio luminosity function at 1.4 GHz to the high frequency ones and estimate the total radio flux in a cluster. At 28.5 GHz, radio confusion is up to 10~100% for small clusters ($M\sim 2\times 10^{14}M_{\odot}$) below redshift z=1, with mor…
If the mean properties of clusters of galaxies are well described by the entropy-driven model, the distortion induced by the cluster population on the blackbody spectrum of the Cosmic Microwave Background radiation is proportional to the total amount of intracluster gas while temperature anisotropies are dominated by the contribution of clusters of about 10^{14} solar masses. This result depends marginally on cluster parameters and it can be used to estimate the number density of clusters with enough hot gas to produce a detectable Sunyaev-Zel'dovich effect. Comparing different cosmological mo…
This brief, general review the Sunyaev-Zeldovich (S-Z) effect includes a description of the calculation of the total intensity change and polarization components, a discussion of the basic properties of the S-Z power spectrum and cluster number counts, and a summary of the main observational results.
We develop a new method for estimating the redshift of galaxy clusters through resolved images of the Sunyaev-Zel'dovich effect (SZE). Our method is based on morphological observables which can be measured by actual and future SZE experiments. The method is tested using a set of high resolution hydrodynamical simulations of galaxy clusters at different redshifts. The method combines the observables in a principal component analysis. We show how this can give an estimate of the redshift of the galaxy clusters. Although the uncertainty in the redshift estimation is large, the method should be us…
According to N-body numerical simulations, the radial pairwise velocities of galaxies have negative skewness in the quasi-nonlinear regime. To understand its origin, we calculate the probability distribution function of the radial pairwise velocity using the Zel'dovich approximation, i.e., an analytical approximation for gravitational clustering. The calculated probability distribution function is in good agreement with the result of N-body simulations. Thus the negative skewness originates in relative motions of galaxies in the clustering process that the infall dominates over the expansion.
We have succeeded in obtaining a precision analytic fitting formula for the exact numerical results of the relativistic corrections to the thermal Sunyaev-Zeldovich effect for clusters of galaxies which has a 1% accuracy for the crossover frequency region where the thermal thermal Sunyaev-Zeldovich effect signal changes from negative to positive sign. The fitting has been carried out for the ranges 0.020 < theta < 0.035 and 0 < X < 15, where theta= kTe/mc^{2}, X = omega/kT0, Te is the electron temperature, omega is the angular frequency of the photon, and T0 is the temperature of the cosmic mi…
We describe a detailed analytic model for predicting statistical quantities (such as number counts, redshift distributions and sizes) of clusters detected in blank-field, thermal Sunyaev-Zel'dovich effect experiments. We include in this model the possibility of non-Gaussian density perturbations in the early Universe and also describe a simple model for the effects of preheating on cluster Sunyaev-Zel'dovich effect fluxes. We use this model to explore the current state of the theoretical uncertainties present in this type of analytic modelling, highlighting where further improvement will be ne…
We report the first detection of the Sunyaev-Zel'dovich increment on the cosmic microwave background (CMB) at submillimetre wavelengths in the direction of a cluster of galaxies.It was achieved towards the rich cluster Abell 2163, using the PRONAOS 2-metre stratospheric telescope. Together with data from the SuZIE, Diabolo, and ISO-PHT experiments, these measurements, for the first time, give a complete picture of the far-infrared to millimetre spectral energy distribution of the diffuse emission toward a cluster of galaxies. It clearly shows the positive and negative parts of the S.Z. effect …
The radiative transfer equations for multiple inverse Compton scattering of the Cosmic Microwave Background Radiation (CMBR) by the hot intra-cluster electrons are solved numerically. The spherical isothermal and inhomogeneous $β$ model has been considered for the electron distribution. The anisotropy of the CMBR caused by scattering, known as thermal Sunyaev-Zel'dovich effect, along the radial axis of the medium is compared with the analytical solution of Kompaneets equation. The X-ray data of several clusters of galaxies at low redshifts provide an estimation of the central electron density …
We address the question of whether the angular power spectrum of the thermal Sunyaev-Zel'dovich (SZ) sky is further distorted by weak gravitational lensing of foreground large-scale structures. Using an analytic approach to both gaseous and dark halo models, we show that the contamination of weak lensing in the measurement of SZ power power is negligibly small, and relatively corrections |ΔC_l|/C_l are less than 3% up to l=10^5. This arises from both the weaker gravitational potentials of low-redshift matter inhomogeneities that can act as lenses for SZ sources (clusters) and the shallower sha…
We present 30 GHz Sunyaev Zel'dovich (SZ) observations of a sample of four galaxy clusters with a prototype of the One Centimetre Receiver Array (OCRA-p) which is mounted on the Torun 32-m telescope. The clusters (Cl0016+16, MS0451.6-0305, MS1054.4-0321 and Abell 2218) are popular SZ targets and serve as commissioning observations. All four are detected with clear significance (4-6 sigma) and values for the central temperature decrements are in good agreement with measurements reported in the literature. We believe that systematic effects are successfully suppressed by our observing strategy. …
We extend the formalism for the calculation of the relativistic corrections to the Sunyaev-Zel'dovich effect for clusters of galaxies and include the multiple scattering effects in the isotropic approximation. We present the results of the calculations by the Fokker-Planck expansion method as well as by the direct numerical integration of the collision term of the Boltzmann equation. The multiple scattering contribution is found to be very small compared with the single scattering contribution. For high-temperature galaxy clusters of kT=15keV, the ratio of the both contributions is -0.2% in th…
X-ray background surveys indicate the likely presence of diffuse warm gas in the Local Super Cluster (LSC), in accord with expectations from hydrodynamical simulations. We assess several other manifestations of warm LSC gas; these include anisotropy in the spatial pattern of cluster Sunyaev-Zeldovich (S-Z) counts, its impact on the CMB temperature power spectrum at the lowest multipoles, and implications on measurements of the S-Z effect in and around the Virgo cluster.
We investigate the error implied by the use of the Zel'dovich approximation to set up the initial conditions at a finite redshift zi in numerical simulations. Using a steepest-descent method developed in a previous work we derive the probability distribution P(delta_R) of the density contrast in the quasi-linear regime. This also provides its dependence on the redshift zi at which the simulation is started. Thus, we find that the discrepancy with the exact pdf (defined by the limit zi->infinity) is negligible after the scale factor has grown by a factor a/a_i>5, for scales which were initially…
We show how the temperature and the polarisation of the cosmic microwave background are affected by bulk rotation of clusters of galaxies owing to the kinetic Sunyaev-Zeldovich effect. The main effects of rotation are (i) a shift of the position of the peak of the temperature fluctuation relative to the center of the cluster by a few percent of the core radius and (ii) a tilt of the direction of the plane of linear polarisation by several degrees.
We predict the level of small-scale anisotropy in the cosmic microwave background (CMB) due to the Sunyaev--Zel'dovich (SZ) effect for the ensemble of cosmological models that are consistent with current measurements of large-scale CMB anisotropy. We argue that the recently reported detections of the small-scale (arcminutes) CMB anisotropy are only marginally consistent with being the SZ effect when cosmological models are calibrated to the existing primary CMB data on large scales. The discrepancy is at more than 2-2.5 sigma, and is mainly due to a lower sigma_8 <0.8 favored by the primary CM…
We consider the role of the galactic kinetic Sunyaev Zeldovich (SZ) effect as a CMB foreground. While the galactic thermal Sunyaev Zeldovich effect has previously been studied and discarded as a potential CMB foreground, we find that the kinetic SZ effect is dominant in the galactic case. We analyse the detectability of the kinetic SZ effect by means of an optimally matched filter technique applied to a simulation of an ideal observation. We obtain no detection, getting a S/N ratio of 0.1, thereby demonstrating that the kinetic SZ effect can also safely be ignored as a CMB foreground. However …
