The Planck satellite is expected to improve the measurement of most cosmological parameters by several factors with respect to current WMAP results. The actual performance may depend upon various aspects of the data analysis. In this paper we analyse the impact of specifics of the data analysis on the actual final results. We also explore the synergies in combining Planck results with future galaxy surveys. We find that Planck will improve constraints on most cosmological parameters by a factor 3-4 and on the tensor-to-scalar ratio r by a factor 9. Also inflationary parameters, like r, n_s and n_run, are no longer degenerate. The tensor spectral index, however, is little constrained. A combination of the 70 to 143 GHz channels will contain ~90% of all possible information, with 143 GHz polarisation information carrying about half of the constraining power on r. Also, the error on r degrades by a factor 2 if no B modes are included in the analysis. High-l temperature information is essential for determination of n_s and Ω_b, while improving noise properties increase the l-range where Planck would be cosmic variance limited in polarisation, with a significant improvement on the determination of r, τand A_s. However, a sub-percent difference in the FWHM used in the data analysis with respect to the one in the map will result in a bias for several parameters. Finally, Planck will greatly help future missions like LSST and CIP reach their potentials by providing tight constraints on parameters like n_s and n_run. Considering Planck together with these probes will help in breaking degeneracies between Ω_K and Ω_Λor Ω_dm and f_ν, resulting in improvements of several factors in the error associated to these parameters.
The recent WMAP3 results have placed measurements of the spectral index n_S in an interesting position. While parameter estimation techniques indicate that the Harrison-Zel'dovich spectrum n_S=1 is strongly excluded (in the absence of tensor perturbations), Bayesian model selection techniques reveal that the case against n_S=1 is not yet conclusive. In this paper, we forecast the ability of the Planck satellite mission to use Bayesian model selection to convincingly exclude (or favour) the Harrison-Zel'dovich model.
Planck will be the first mission to map the entire cosmic microwave background (CMB) sky with mJy sensitivity and resolution better than 10'. The science enabled by such a mission spans many areas of astrophysics and cosmology. In particular it will lead to a revolution in our understanding of primary and secondary CMB anisotropies, the constraints on many key cosmological parameters will be improved by almost an order of magnitude (to sub-percent levels) and the shape and amplitude of the mass power spectrum at high redshift will be tightly constrained.
Observations of redshift-space distortions in spectroscopic galaxy surveys offer an attractive method for observing the build-up of cosmological structure, which depends both on the expansion rate of the Universe and our theory of gravity. In this paper we present a formalism for forecasting the constraints on the growth of structure which would arise in an idealized survey. This Fisher matrix based formalism can be used to study the power and aid in the design of future surveys.
The WMAP first year detection of a high redshift reionization through its imprints on CMB anisotropy T and TE mode angular power spectra calls for a better comprehension of the universe ionization and thermal history after the standard recombination. Different reionization mechanisms predict different signatures in the CMB, both in temperature and polarization anisotropies and in spectral distortions. The Planck capability to distinguish among different scenarios through its sensitivity to T, TE, and E mode angular power spectra is discussed. Perspectives open by future high sensitivity experi…
For 40 years, the cosmic microwave background (CMB) has been the most important source of information about the geometry and contents of the Universe. Even so, only a small fraction of the information available in the CMB has been extracted to date. Planck, the third space CMB mission after COBE and WMAP, is designed to extract essentially all of the information in the CMB temperature anisotropies. Planck will also measure to high accuracy the polarization of CMB anisotropies, which encodes not only a wealth of cosmological information but also provides a unique probe of the thermal history of…
We propose the relation $M_Λ\sim (M_{Pl} M_U)^{1/2}$ where $M_Λ$, $M_{Pl},$ and $M_U$ denote the mass scale associated with the cosmological constant, the gravitational interaction, and the size of the universe respectively.
We study the complementarity between the cosmological information obtainable with the Planck surveyour and the large scale structure (LSS) redshift surveys in LambdaCHDM cosmologies. We compute the initial full phase-space neutrino distribution function for LambdaCHDM models by using numerical simulations. As initial condition we adopt the HDM density fluctuation power spectrum normalized on the basis of the analysis of the local cluster X-ray temperature function and derive the initial neutrino phase-space distribution at each spatial wave number k by using the Zel'dovich approximation. These…
We study the clustering properties of the galaxy clusters detectable for the Planck satellite due to their thermal Sunyaev-Zel'dovich effect. We take the past light-cone effect and the redshift evolution of both the underlying dark matter correlation function and the cluster bias factor into account. A theoretical mass-temperature relation allows us to convert the sensitivity limit of a catalogue into a minimum mass for the dark matter haloes hosting the clusters. We confirm that the correlation length is an increasing function of the sensitivity limits defining the survey. Using the expected …
Data from future high-precision Cosmic Microwave Background (CMB) measurements will be sensitive to the primordial Helium abundance $Y_p$. At the same time, this parameter can be predicted from Big Bang Nucleosynthesis (BBN) as a function of the baryon and radiation densities, as well as a neutrino chemical potential. We suggest to use this information to impose a self-consistent BBN prior on $Y_p$ and determine its impact on parameter inference from simulated Planck data. We find that this approach can significantly improve bounds on cosmological parameters compared to an analysis which treat…
We present the cosmological distance errors achievable using the baryon acoustic oscillations as a standard ruler. We begin from a Fisher matrix formalism that is upgraded from Seo & Eisenstein (2003). We isolate the information from the baryonic peaks by excluding distance information from other less robust sources. Meanwhile we accommodate the Lagrangian displacement distribution into the Fisher matrix calculation to reflect the gradual loss of information in scale and in time due to nonlinear growth, nonlinear bias, and nonlinear redshift distortions. We then show that we can contract the m…
It has been long recognised that, besides being a formidable experiment to observe the primordial CMB anisotropies, Planck will also have the capability to detect galaxy clusters via their SZ imprint. In this paper constraints on cosmological parameters derivable from the Planck cluster candidate sample are examined for the first time as a function of cluster sample selection and purity obtained from realistic simulations of the microwave sky at the Planck observing frequency bands, observation process modelling and a cluster extraction pipeline. In particular, we employ a multi-frequency matc…
Einstein's theory of general relativity, which contains a universal value of the Planck mass, has been so far successfully invoked to explain gravitational dynamics from sub-millimeter scales to the scale of the cosmological horizon. However, one may envisage that in alternative theories of gravity, the effective value of the Planck mass (or Newton's constant), which quantifies the coupling of matter to metric perturbations, can run on the cosmological horizon scale. In this letter, we study the consequences of a glitch in the Planck mass from sub-horizon to super-horizon scales. We first give…
The major theoretical limitation for extracting cosmological parameters from the CMB sky lies in the precision with which we can calculate the cosmological recombination process. Uncertainty in the details of hydrogen and helium recombination could effectively increase the errors or bias the values of the cosmological parameters derived from the Planck satellite, for example. Here we modify the cosmological recombination code RECFAST by introducing one more parameter to reproduce the recent numerical results for the speed-up of the helium recombination. Together with the existing hydrogen fudg…
The Casimir energy density calculated for a spherical shell of radius equal to the size of the Universe projected back to the Planck time is almost equal to the present day critical density. Is it just a coincidence, or is it a solution to the `cosmic dark energy' and the `cosmic coincidence' problems? The correspondence is too close to be ignored as a coincidence, especially since this solution fits the conceptual and numerical ideas about the dark energy, and also answers why this energy is starting to dominate at the present era in the evolution of the Universe.
In the framework of inflation, scales which nowadays correspond to large scale structures were smaller than the Planck length at the beginning of inflation. Therefore, measurements of CMBR anisotropy or surveys of galaxies and of clusters of galaxies could help us to probe physics beyond the Planck scale. In these proceedings, we study how the inflationary observables depend on trans-Planckian physics. It is found that there exist cases where adiabaticity can be violated and the primordial spectrum of the quantum cosmological perturbations modified. These cases correspond to rather drastic alt…
We consider a class of spatially flat cold dark matter (CDM) models, with a cosmological constant and a broken-scale-invariant (BSI) steplike primordial spectrum of adiabatic perturbations, previously found to be in very good agreement with observations. Performing a Fisher matrix analysis, we show that in case of a large gravitational waves (GW) contribution some free parameters (defining the step) of our BSI model can be extracted with remarkable accuracy by the Planck satellite, thanks to the polarisation anisotropy measurements. Further, cosmological parameters can still be found with very…
Starting from generic quantum effects at the Planck scale M_P, we find that the renormalization group running of the cosmological constant (CC) at low energies is possible if there is a smooth decoupling of all massive particles from M_P to the mass of the lightest neutrino. We discuss the theoretical implications of this running for the ``old'' and ``new'' cosmological constant problems. Interestingly enough, the CC running implies a strong relationship between quantum field theory and cosmology, which should be observable in the near future in experiments such as SNAP through the measurement…
We apply the effective field theory approach to the coupled metric-inflaton system, in order to investigate the impact of higher dimension operators on the spectrum of scalar and tensor perturbations in the short-wavelength regime. In both cases, effective corrections at tree-level become important when the Hubble parameter is of the order of the Planck mass, or when the physical wave number of a cosmological perturbation mode approaches the square of the Planck mass divided by the Hubble constant. Thus, the cut-off length below which conventional cosmological perturbation theory does not appl…
It is possible that the scale of gravity, parameterized by the apparent Planck mass, may obtain different values within different universes in an encompassing multiverse. We investigate the range over which the Planck mass may scan while still satisfying anthropic constraints. The window for anthropically allowed values of the Planck mass may have important consequences for landscape predictions. For example, if the likelihood to observe some value of the Planck mass is weighted by the inflationary expansion factors of the universes that contain that value, then it appears extremely unlikely t…
We construct a semiclassical FLRW cosmological model assuming a running cosmological constant (CC). It turns out that the CC becomes variable at arbitrarily low energies due to the remnant quantum effects of the heaviest particles, e.g. the Planck scale physics. These effects are universal in the sense that they lead to a low-energy structure common to a large class of high-energy theories. Remarkably, the uncertainty concerning the unknown high-energy dynamics is accumulated into a single parameter ν, such that the model has an essential predictive power. Future Type Ia supernovae experiments…
We consider the detection possibilities of isocurvature fluctuations in the future CMB satellite experiments MAP and Planck for different cosmological reference models. We present a simultaneous 10 parameter fit (8 for the case of open model) to determine the correlations between the cosmological parameters, including isocurvature cold dark matter contribution to the anisotropy. Assuming that polarization information can be fully exploited, we find that an isocurvature perturbation can be detected by the Planck Surveyor if the ratio of the initial isocurvature and adiabatic perturbation amplit…
We investigate the constraints on cosmological parameters especially for EoS of dark energy, inflationary parameters, neutrino mass and curvature of universe using simulated Planck data. Firstly we determine cosmological parameters with current observations including ESSENCE, WMAP3, Boomerang-2K2, CBI, VSA, ACBAR, SDSS LRG and 2dFGRS, and take best-fit model as the fiducial model in simulations. In simulations we pay attention to the effects of dynamical dark energy in determination of cosmological parameters. We add simulated SNAP data to do all the simulations. Using present data, we find Qu…
Future sattelite (MAP and Planck) balloon and ground based experiments will the determine the basic cosmological parameters within a few percent. We examine here the effect of this on constraining the SUSY parameter space for supergravity R-parity conserving models (with tanbeta < 25) for the cases of nuCDM and LambdaCDM cosmological models. For the nuCDM (LambdaCDM) models, the gluino mass is restricted by m_g~ < 720(540)GeV. In both cases, the cosmological constraints are sensitive to non-universal SUSY soft breaking producing a lower bound m_g~ > 400GeV in some regions and for the nuCDM mod…
It has recently been suggested that Planck scale physics may effect the evolution of cosmological fluctuations in the early stages of cosmological inflation in a non-trivial way, leading to an excited state for modes whose wavelength is super-Planck but sub-Hubble. In this case, the issue of how this excited state back-reacts on the background space-time arises. In fact, it has been suggested that such back-reaction effects may lead to tight constraints on the magnitude of possible deviations from the usual predictions of inflation. In this note we discuss some subtle aspects of this back-reac…
We investigate the insensitivity of the predictions of inflationary models with respect to modifications of Planck energy physics. The modification we consider consists in replacing the usual dispersion relation by nonlinear ones. This way of addressing the problem has recently recieved attention and contradictory results were found. Our main result is to show that the adiabaticity of the mode propagation and the separation of two scales of interest, the Planck scale and the cosmological horizon scale, are sufficient conditions for the predictions to be unchanged. We then show that almost all …
The implementation of a Planck-scale high frequency and short wavelength cutoff in quantum theories on expanding backgrounds may have potentially nontrivial implications, such as the breaking of local Lorentz invariance and the existence of a yet unknown mechanism for the creation of vacuum modes. In scenarios where inflation begins close to the cutoff scale, these effects could have observable consequences as trans-Planckian modes are redshifted to cosmological scales. In close analogy with similar studies of Hawking radiation, a simple theory of a minimally coupled scalar field in de Sitter …
