scholarly journals The kinematic Sunyaev–Zel’dovich effect of the large-scale structure (II): the effect of modified gravity

2018 ◽  
Vol 481 (2) ◽  
pp. 2497-2506 ◽  
Author(s):  
M Roncarelli ◽  
M Baldi ◽  
F Villaescusa-Navarro

ABSTRACT The key to understand the nature of dark energy lies in our ability to probe the distant Universe. In this framework, the recent detection of the kinematic Sunyaev–Zel’dovich (kSZ) effect signature in the cosmic microwave background obtained with the South Pole Telescope (SPT) is extremely useful since this observable is sensitive to the high-redshift diffuse plasma. We analyse a set of cosmological hydrodynamical simulation with four different realizations of a Hu & Sawicki f(R) gravity model, parametrized by the values of $\overline{f}_{\rm R,0}$= (0, −10−6, −10−5, −10−4), to compute the properties of the kSZ effect due to the ionized Universe and how they depend on $\overline{f}_{\rm R,0}$ and on the redshift of reionization, zre. In the standard General Relativity limit ($\overline{f}_{\rm R,0}$= 0) we obtain an amplitude of the kSZ power spectrum of $\mathcal {D}^{\rm kSZ}_{3000}$$= 4.1\,$$\mu$K2 (zre= 8.8), close to the +1σ limit of the $\mathcal {D}^{\rm kSZ}_{3000}$$= (2.9\pm 1.3)\,$$\mu$K2 measurement by SPT. This corresponds to an upper limit on the kSZ contribute from patchy reionization of $\mathcal {D}^{\rm kSZ,patchy}_{3000}$$\lt 0.9\,$$\mu$K2 (95 per cent confidence level). Modified gravity boosts the kSZ signal by about 3, 12, and 50 per cent for $\overline{f}_{\rm R,0}$=(− 10−6, −10−5, −10−4), respectively, with almost no dependence on the angular scale. This means that with modified gravity the limits on patchy reionization shrink significantly: for $\overline{f}_{\rm R,0}$=−10−5 we obtain $\mathcal {D}^{\rm kSZ,patchy}_{3000}$$\lt 0.4\,$$\mu$K2. Finally, we provide an analytical formula for the scaling of the kSZ power spectrum with zre and $\overline{f}_{\rm R,0}$ at different multipoles: at ℓ = 3000 we obtain $\mathcal {D}^{\rm kSZ}_{3000}$ ∝ zre$^{0.24}\left(1+\sqrt{\left|\overline{f}_{\rm R,0}\right|}\right)^{41}$.

2005 ◽  
Vol 14 (08) ◽  
pp. 1347-1364 ◽  
Author(s):  
XIULIAN WANG ◽  
BO FENG ◽  
MINGZHE LI ◽  
XUE-LEI CHEN ◽  
XINMIN ZHANG

In the "natural inflation" model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections produce oscillating features in the primordial fluctuation power spectrum, which are not entirely excluded by the current observations and may be detectable in high precision data of cosmic microwave background (CMB) anisotropy and large scale structure (LSS) observations.


1990 ◽  
Vol 139 ◽  
pp. 333-343 ◽  
Author(s):  
G. De Zotti ◽  
L. Danese ◽  
L. Toffolatti ◽  
A. Franceschini

We review the data on the spectrum and isotropy of the microwave background radiation and the astrophysical processes that may produce spectral distortions and anisotropies. As yet no fully satisfactory explanation has been found for the submillimeter excess observed by Matsumoto et al. (1988). The most precise data at λ > 1 mm disagree with nonrelativistic comptonization models which match the excess. Distortions produced by a very hot intergalactic medium yielding the X-ray background do not fit the submillimeter data. Very special requirements must be met for the interpretation in terms of high-redshift dust emission to work.Reported anisotropies on scales of several degrees and of tens of arcsec may be produced, at least in part, by discrete sources. Because the best experiments at cm wavelengths are close to the confusion limit, they provide interesting information on the large-scale distribution of radio sources.


2019 ◽  
Vol 491 (3) ◽  
pp. 3165-3181 ◽  
Author(s):  
Robin E Upham ◽  
Lee Whittaker ◽  
Michael L Brown

ABSTRACT We present the exact joint likelihood of pseudo-Cℓ power spectrum estimates measured from an arbitrary number of Gaussian cosmological fields. Our method is applicable to both spin-0 fields and spin-2 fields, including a mixture of the two, and is relevant to cosmic microwave background (CMB), weak lensing, and galaxy clustering analyses. We show that Gaussian cosmological fields are mixed by a mask in such a way that retains their Gaussianity and derive exact expressions for the covariance of the cut-sky spherical harmonic coefficients, the pseudo-aℓms, without making any assumptions about the mask geometry. We then show that each auto or cross-pseudo-Cℓ estimator can be written as a quadratic form, and apply the known joint distribution of quadratic forms to obtain the exact joint likelihood of a set of pseudo-Cℓ estimates in the presence of an arbitrary mask. We show that the same formalism can be applied to obtain the exact joint likelihood of quadratic maximum likelihood power spectrum estimates. Considering the polarization of the CMB as an example, we show using simulations that our likelihood recovers the full, exact multivariate distribution of EE, BB, and EB pseudo-Cℓ power spectra. Our method provides a route to robust cosmological constraints from future CMB and large-scale structure surveys in an era of ever-increasing statistical precision.


2005 ◽  
Vol 216 ◽  
pp. 28-34
Author(s):  
S. L. Bridle ◽  
A. M. Lewis ◽  
J. Weller ◽  
G. Efstathiou

We reconstruct the shape of the primordial power spectrum from the latest cosmic microwave background data, including the new results from the Wilkinson Microwave Anisotropy Probe (WMAP), and large scale structure data from the two degree field galaxy redshift survey (2dFGRS). We discuss two parameterizations taking into account the uncertainties in four cosmological parameters. First we parameterize the initial spectrum by a tilt and a running spectral index, finding marginal evidence for a running spectral index only if the first three WMAP multipoles (ℓ = 2, 3, 4) are included in the analysis. Secondly, to investigate further the low CMB large scale power, we modify the conventional power-law spectrum by introducing a scale above which there is no power. We find a preferred position of the cut at kc ∼ 3 × 10--4 Mpc--1 although kc = 0 (no cut) is not ruled out.


1998 ◽  
Vol 11 (1) ◽  
pp. 487-491
Author(s):  
J. Huchra ◽  
E. Tollestrup ◽  
S. Schneider ◽  
M. Skrutski ◽  
T. Jarrett ◽  
...  

With the current convergence of determinations of the Hubble Constant (e.g. The Extragalactic Distance Scale, 1997, Livio, Donahue and Panagia, eds.) to values within ±25% rather than a factor of two, and the clear possibility of determining q0 using high redshift supernovae (Garnavich et al. 1998), the major remaining problem in observational cosmology is the determination of Ω — what is the dark matter, how much is there, and how is it distributed? The most direct approach to the last two parts of the question has been to study galaxy dynamics, first through the motions of galaxies in binaries, groups and clusters, and in the last decade and a half, driven by the observation of our motion w.r.t. the Cosmic Microwave Background (CMB) and thenotion that DM must be clumped on larger scales than galaxy clusters if (Ω is to be unity, through the study of large scale galaxy flows. The ratio of the mass density to the closure mass density, Ω, is thought by most observers to be ~0.1-0.3, primarily based on the results of dynamical measurements of galaxy clusters and, more recently, gravitational lensing studies of clusters. In contrast, most theoretical cosmologists opt for a high density universe, Ω = 1.0, based on the precepts of the inflation scenario, the difficulty of forming galaxies in low density models given the observed smoothness of the microwave background radiation, and the observational evidence from the matching of the available large scale flow measurements (and the absolute microwave background dipole velocity) to the local density field. However this last result is extremely controversial—matching the velocity field to the density field derived from IRAS (60μ) selected galaxy samples yields high Ω values (e.g., Dekel et al. 1993) but matching to optically selected samples yields low values (Hudson 1994; Lahav et al. 1994; Santiago et al. 1995). On small scales, the high Ω camp argues that the true matter distribution is much more extended than the distribution of galaxies, so the dynamical mass estimates are biased low.


2002 ◽  
Vol 199 ◽  
pp. 54-55 ◽  
Author(s):  
B.F. Roukema ◽  
G.A. Mamon

The peak in the power spectrum at ≈ 130h−1 Mpc at low redshifts provides a standard ruler in comoving space. This scale is shown to be present in the observed quasar distribution at z ∼ 2. This implies strong constraints on the density parameter, Ω0, and weaker constraints on the cosmological constant, λ0. Independently of λ0 (in the range λ0 ∊ [0, 1]), the constraint is 0.1 < Ω0 < 0.45 (68% confidence limit).Combination of the power spectrum peak method with very independent results from the supernovae Type Ia method yields Ω0 = (0.30 ± 0.11) + (0.57 ± 0.11)(λ0 −0.7), 0.55 < λ0 < 0.95, (68% confidence limits) without assuming Ω0 + λ0 = 1. This supports the almost flat, perturbed Friedmann-Lemaître-Robertson-Walker model, independently of any cosmic microwave background observations.


1988 ◽  
Vol 130 ◽  
pp. 7-14 ◽  
Author(s):  
David T. Wilkinson

Recent measurements of the spectrum and anisotropy of the cosmic microwave may be showing deviations from a perfectly homogeneous blackbody flux. Improved spectral measurements at wavelengths of 3 cm and 1.2 cm disagree weakly; and new results from a rocket show large excess flux at wavelengths of 0.71 and 0.48 mm. The same instrument measured a radiation temperature at λ = 1.16 mm of 2.795 ± 0.018 K in good agreement with results at longer wavelengths. The observed excess flux at short wavelengths may be due to: local contaminants; dust emission from active galaxies at high redshift; or inverse Compton scattering of microwave photons from hot electrons at large redshift (Sunyaev-Zel'dovich effect). Anisotropy of ΔT/T = 3.7 × 10−5 has been reported on an angular scale of 8° at a wavelength of 3 cm. Measurements on a similar angular scale at λ = 6 cm (reported at this meeting) do not show the anisotropy at the flux level expected if Galactic emission were the source of the anisotropy at λ = 3 cm. The standard model has not yet predicted anisotropy this large at 8°, but without doubt it soon will. Long integrations with the Very Large Array at λ = 6 cm are showing resolved structures on angular scales of 15 to 30 arcseconds. Observations at another wavelength are needed to see if these are radio sources at high redshift or perturbations in the 2.77 K radiatoin.


1988 ◽  
Vol 130 ◽  
pp. 513-513
Author(s):  
Yasushi Suto ◽  
Naoteru Gouda ◽  
Misao Sasaki

We have calculated the anisotropies of the cosmic microwave background radiation in a baryon-dominated model (BDM), using a gauge invariant method. The results on a 4.5′ angular scale are as follows (h = 0.5 and initially Zel'dovich power spectrum assumed):


2012 ◽  
Vol 8 (S288) ◽  
pp. 76-79 ◽  
Author(s):  
Bradford Benson ◽  

AbstractThe South Pole Telescope is a 10 meter telescope optimized for sensitive, high-resolution measurements of the cosmic microwave background (CMB) anisotropy and millimeter-wavelength sky. In November 2011, the SPT completed the 2500 deg2 SPT-SZ survey. The survey has led to several major cosmological results, derived from measurements of the fine angular scale primary and secondary CMB anisotropies, the discovery of galaxy clusters via the Sunyaev-Zel'dovich (SZ) effect and the resulting mass-limited cluster catalog, and the discovery of a population of distant, dusty star forming galaxies (DSFGs). In January 2012, the SPT was equipped with a new polarization sensitive camera, SPTpol, which will enable detection of the contribution to the CMB polarization power spectrum from lensing by large scale structure (the so-called “lensing B-modes”) and, on larger angular scales, a detection or improved upper limit on the primordial inflationary signal (“gravitational-wave B-modes”), thereby constraining the energy scale of Inflation. Development is underway for SPT-3G, the third-generation camera for SPT. The SPT-3G survey will cross the threshold from statistical detection of B-mode CMB lensing to imaging the fluctuations at high signal-to-noise; enabling the separation of lensing and inflationary B-modes and improving the constraint on the sum of the neutrino masses Σmν to a level relevant for exploring the neutrino mass hierarchy.


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