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Register a new userKinetic Sunyaev Zeldovich effect in an anisotropic CMB model: measuring low multipoles of the CMB at higher redshifts using intensity and polarization spectral distortions
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We present a novel mathematical formalism that allows to easily compute the expected kinetic Sunyaev Zeldovich (kSZ) signal in intensity and polarization due to an anisotropic primordial Cosmic Microwave Background (CMB). We derive the expected intensity and polarization distortions in the direction of non-moving galaxy clusters and then we generalize our calculations for non-zero peculiar velocity. We show that, in the direction of moving clusters, low CMB multipoles impose intensity and polarization spectral distortions with different frequency dependences. The polarization signal primarily probes the quadrupole moment of the CMB, with a significant contribution from the primordial dipole and octupole moments. For a typical cluster velocity of 1000 km/s, corrections to the quadrupole-induced polarization of a non-moving cluster are of the order of 2-10% between 200-600 GHz, and depend on clusters position on the sky, velocity magnitude and direction of motion. We also find that the angular dependence of the signal varies with frequency of observation. The distinct frequency and angular dependences of the polarization induced by the primordial dipole and octupole can be exploited to measure them despite other physical effects and foregrounds. Contrary to polarization, intensity distortions are affected by all the CMB multipoles, so they cannot be readily used to probe the low multipoles at higher redshifts. However, correlations between intensity and polarization signals, can be used to enhance the signal to noise ratio for the measurements of the primordial dipole, quadrupole and octupole. The more general calculation of the aberration kernel presented in this work has applications reaching beyond the SZ cluster science addressed here. For example, it can be exploited to the deboost/deaberrate CMB multipoles as observed in our local frame.
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We consider the Stokes parameters frequency spectral distortions arising due to Compton scattering of the anisotropic cosmic microwave background (CMB) radiation, the Sunyaev-Zel dovich effect (SZ), towards clusters of galaxies. We single out a very special type of such distortions and find simple analytical formulas for them. We show that this kind of distortion has a very distinctive spectral shape and can be separated from other kinds of contaminants. We demonstrate that this effect gives us an opportunity for an independent estimation of the low-multipole angular CMB anisotropies, such as the dipole, the quadrupole, and the octupole. We also show that, using distorted signals from nearby and distant clusters, one can distinguish between the Sachs-Wolfe and the integrated Sachs-Wolfe effects. The detection of such distortions can be feasible with high-angular resolution and high-sensitivity space missions, such as the upcoming Millimetron Space Observatory experiment.
We consider the effect of the cosmic microwave background (CMB) frequency spectral distortions arising due to the Compton scattering of the anisotropic radiation on Sunyaev-Zeldovich (SZ) clusters. We derive the correction to the thermal SZ effect due to the presence of multipoles with $ell=1,2,3$ in the anisotropy of the CMB radiation. We show that this effect gives us an opportunity for an independent evaluation of the CMB dipole, quadrupole and octupole angular anisotropy in our location using distorted signal from the nearby galaxy clusters and to distinguish between the Sachs-Wolfe (SW) and the Integrated Sachs-Wolfe (ISW) effects by combining such signals from distant and nearby clusters. The future space mission Millimetron will have unprecedented sensitivity, which will make it possible to observe the spectral distortion we are considering.
If the large scale structure of the Universe was created, even partially, via Zeldovich pancakes, than the fluctuations of the CMB radiation should be formed due to bulk comptonization of black body spectrum on the contracting pancake. Approximate formulas for the CMB energy spectrum after bulk comptonization are obtained. The difference between comptonized energy spectra of the CMB due to thermal and bulk comptonization may be estimated by comparison of the plots for the spectra in these two cases.
While the arcminute-scale Cosmic Microwave Background (CMB) anisotropies are due to secondary effects, point sources dominate the total anisotropy power spectrum. At high frequencies the point sources are primarily in the form of dusty, star-forming galaxies. Both Herschel and Planck have recently measured the anisotropy power spectrum of cosmic infrared background (CIB) generated by dusty, star-forming galaxies from degree to sub-arcminute angular scales, including the non-linear clustering of these galaxies at multipoles of 3000 to 6000 relevant to CMB secondary anisotropy studies. We scale the CIB angular power spectra to CMB frequencies and interpret the combined WMAP-7 year and arcminute-scale Atacama Cosmology Telescope (ACT) and South Pole Telescope (SPT) CMB power spectra measurements to constrain the Sunyaev-Zeldovich (SZ) effects. Allowing the CIB clustering amplitude to vary, we constrain the amplitudes of thermal and kinetic SZ power spectra at 150 GHz.
The epoch of reionization is one of the major phase transitions in the history of the universe, and is a focus of ongoing and upcoming cosmic microwave background (CMB) experiments with improved sensitivity to small-scale fluctuations. Reionization also represents a significant contaminant to CMB-derived cosmological parameter constraints, due to the degeneracy between the Thomson-scattering optical depth, $tau$, and the amplitude of scalar perturbations, $A_s$. This degeneracy subsequently hinders the ability of large-scale structure data to constrain the sum of the neutrino masses, a major target for cosmology in the 2020s. In this work, we explore the kinematic Sunyaev-Zeldovich (kSZ) effect as a probe of reionization, and show that it can be used to mitigate the optical depth degeneracy with high-sensitivity, high-resolution data from the upcoming CMB-S4 experiment. We discuss the dependence of the kSZ power spectrum on physical reionization model parameters, as well as on empirical reionization parameters, namely $tau$ and the duration of reionization, $Delta z$. We show that by combining the kSZ two-point function and the reconstructed kSZ four-point function, degeneracies between $tau$ and $Delta z$ can be strongly broken, yielding tight constraints on both parameters. We forecast $sigma(tau) = 0.003$ and $sigma(Delta z) = 0.25$ for a combination of CMB-S4 and Planck data, including detailed treatment of foregrounds and atmospheric noise. The constraint on $tau$ is nearly identical to the cosmic-variance limit that can be achieved from large-angle CMB polarization data. The kSZ effect thus promises to yield not only detailed information about the reionization epoch, but also to enable high-precision cosmological constraints on the neutrino mass.
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