History of stellar evolution at high redshifts: Implications for the CMB E-mode polarization

The epoch of the end of reionization and the Thomson optical depth to the cosmic microwave background depend on the power spectrum amplitude on small scales and on the ionizing photon emissivity per unit mass in collapsed halos. In this paper is investigated the role of the radiative feedback effects for the temporal evolution of the ionizing emissivity. It is shown that the observational constrains on hydrogen photo-ionization rate based on Ly-$\alpha$, Ly-$\beta$ and Ly-$\gamma$ Gunn-Peterson troughs and an electron optical depth consistent with the latest CMB measurements requires an emissivity of $\sim$10 ionizing photons per baryon and Hubble time at $z=6$. Through E-mode CMB polarization power spectrum measurements, it is expected that Planck experiment will have the sensitivity to distinguish between different histories of stellar evolution.Comment: 5 pages and 7 figures Open Questions in Cosmology, 22 - 26 August, 2005, Garching, German

Higgs mass from cosmological and astrophysical measurements

For a robust interpretation of upcoming observations from Planck and LHC experiments it is imperative to understand how the inflationary dynamics of a non-minimally coupled Higgs scalar field may affect the degeneracy of the inflationary observables. We constrain the inflationary observables and the Higgs boson mass during observable inflation by fitting the the Higgs inflationary potential directly to WMAP5+BAO+SN data. We obtain a Higgs mass a value of 143.73+14.97/-6.31 GeV at 95% CL for the central value of top quark mass. We also show that the inflation driven by a non-minimally coupled scalar field leads to significant changes of the inflationary parameters when compared with the similar constraints from the standard inflation.Comment: 17 pages, 3 figure

Lookback time and Chandra constrains on cosmological parameters

In this paper we combine the WMAP7 with lookback time and Chandra gas fraction data to constrain the main cosmological parameters and the equation of state for the dark energy. We find that the lookback time is a good measurement that can improve the determination of the equation of state for the dark energy with regard to other external data sets. We conclude that larger lookback time data set will further improve our determination of the cosmological parameters.Comment: 10 pages, 2 figures; Romanian Reports in Physics, Volume 63, Number 3, 201

Cosmological Constraints on the Higgs Boson Mass

For a robust interpretation of upcoming observations from PLANCK and LHC experiments it is imperative to understand how the inflationary dynamics of a non-minimally coupled Higgs scalar field with gravity may affect the determination of the inflationary observables. We make a full proper analysis of the WMAP7+SN+BAO dataset in the context of the non-minimally coupled Higgs inflation field with gravity. For the central value of the top quark pole mass m_T=171.3 GeV, the fit of the inflation model with non-minimally coupled Higgs scalar field leads to the Higgs boson mass between 143.7 and 167 GeV (95% CL). We show that the inflation driven by a non-minimally coupled scalar field to the Einstein gravity leads to significant constraints on the scalar spectral index and tensor-to-scalar ratio when compared with the similar constraints tensor to from the standard inflation with minimally coupled scalar field. We also show that an accurate reconstruction of the Higgs potential in terms of inflationary observables requires an improved accuracy of other parameters of the Standard Model of particle physics as the top quark mass and the effective QCD coupling constant.Comment: 23 pages, 4 figures, accepted for publication in The Astrophysical Journa

Cosmological evidence for leptonic asymmetry after Planck

Recently, the Planck satellite found a larger and most precise value of the matter energy density, that impacts on the present values of other cosmological parameters such as the Hubble constant, the present cluster abundances and the age of the Universe. The existing tension between Planck determination of these parameters in the frame of the base LambdaCDM model and their direct measurements generated lively discussions and several interpretations. In this paper we quantify this tension by exploring several extensions of the base LambdaCDM model that include the leptonic asymmetry. We set bounds on the radiation content of the Universe and neutrino properties by using the latest cosmological measurements, imposing also self-consistent BBN constraints on the primordial helium abundance. For all cosmological asymmetric models we find the preference of cosmological data for smaller values of active and sterile neutrino masses. This increases the tension between cosmological and short baseline neutrino oscillation data that favor a sterile neutrino with the mass of around 1 eV. For the case of degenerate massive neutrinos, we find that the discrepancies with direct determinations of the Hubble constant, the present cluster abundances and the age of the Universe are alleviated at ~ 1.3 sigma for all leptonic asymmetric models. We also find ~2 sigma statistical evidence of the preference of cosmological data for the normal neutrino hierarchy. This is more evident for the case of cosmological models involving leptonic asymmetry and three massive neutrino species. We conclude that the current cosmological data favor the leptonic asymmetric extension of the base LambdaCDM model and normal neutrino mass hierarchy over the models with additional sterile neutrino species and/or inverted neutrino mass hierarchy.Comment: 18 pages, 7 figures, submitted to Journal of Cosmology and Astroparticle Physic

From WMAP to Planck: Exact reconstruction of 4- and 5-dimensional inflationary potential from high precision CMB measurements

We make a more general determination of the inflationary observables in the standard 4-D and 5-D single-field inflationary scenarios, by the exact reconstruction of the dynamics of the inflation potential during the observable inflation with minimal number of assumptions: the computation does not assume the slow-roll approximation and is valid in all regimes if the field is monotonically rolling down its potential. Making use of the {\em Hamilton-Jacobi} formalism developed for the 5-D single-field inflation model,we compute the scale dependence of the amplitudes of the scalarand tensor perturbations by integrating the exact mode equation. We analyze the implications of the theoretical uncertainty in the determination of the reheating temperature after inflation on the observable predictions of inflation and evaluate its impact on the degeneracy of the standard inflation consistency relation.Comment: 30 pages and 7 figures processed with LATEX macros v5.2 accepted for publication in Astrophysical Journa

WMAP 3-year polarization data: Implications for the reionization history

We show that the delay of structure formation can not fully account for the reduction of electron optical depth from WMAP1 to WMAP3 when the radiative transfer effects and feedback mechanisms are took into account in computing the reionization history of the Universe. We also show that a PopIII stellar cluster with a mass of 80Mo and a heavy Larson initial mass function has an ionizing efficiency high enough to account for WMAP3 results, while in the case of WMAP1, a higher stellar mass of 1000Mo was required

Cosmological Implications of Massive Neutrinos

The massive neutrinos gravitational infall and their inprints left on the CMB temperature and matter density fluctuations power spectra are analysed taking into account the massive neutrino properties: the mass degeneracy, the phase space mixing, the lepton asymmetry

Subdominant Dark Matter sterile neutrino resonant production in the light of Planck

Few independent detections of a weak X-ray line at an energy of $\sim$3.5 keV seen toward a number of astrophysical sites have been reported. If this signal will be confirmed to be the signature of decaying DM sterile neutrino with a mass of ~7.1 keV, then the cosmological observables should be consistent with its properties. In this paper we make a coupled treatment of the weak decoupling, primordial nucleosynthesis and photon decoupling epochs in the sterile neutrino resonant production scenario, including the extra radiation energy density via N_eff. We compute the radiation and matter perturbations including the full resonance sweep solution for active-sterile flavor conversion in the expanding Universe. We show that the cosmological measurements are in agreement with sub-dominant DM sterile neutrino resonant production with following parameters (errors at 95 CL): sterile neutrino mass 6.08 \pm 3.22 keV, mixing angle \sin^2 2 \theta < 5.61 x 10^{-10}, lepton number per flavor L_4 = 1.23 \pm 0.04 and sterile neutrino mass fraction f_\nu < 0.078. Our results are in good agreement with the sterile neutrino resonant production parameters inferred in Ref. [62] from the linear large scale structure constraints to produce full Dark Matter density.Comment: 20 pages, 8 figures; Accepted for publication in JCAP after major revisio

Cosmological reionization after WMAP: perspectives from PLANCK and future CMB missions

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 experiments on the CMB polarization anisotropy and spectrum are also presented.Comment: 19 pages, 10 figures, to be published in proc. JENAM 2004 meeting "The many scales in the Universe", Granada, Spain, 13-17 Sept. 200