The Radiation Budget of the Universe

2010

Author(s): Caramete, A (Caramete, Ana)

Edited by: Trache L; Stoica S; Smirnov A

Source: EXOTIC NUCLEI AND NUCLEAR - PARTICLE ASTROPHYSICS III: FROM NUCLEI TO STARS  Book Series: AIP Conference Proceedings  Volume: 1304  Pages: 444-448  Published Date: 2010   

Abstract: This work sets bounds on the radiation content of the Universe and neutrino properties by using the WMAP-7 year CMB measurements complemented with most of the existing CMB and LSS data, imposing also self-consistent BBN constraints on the primordial helium abundance, Y-p. Lepton asymmetric cosmological models are considered, parametrized by the neutrino degeneracy parameter xi(v) and the variation of the relativistic degrees of freedom, Delta N-eff(oth), due to possible other physical processes occurred between BBN and structure formation epochs. The results bring an important improvement over the same parameters obtained by using the WMAP data alone, showing that the LSS measurements are useful tools in constraining the radiation content of the Universe during BBN.

Accession Number: WOS:000286911100059

Conference Title: Carpathian Summer School of Physics Conference

Conference Date: JUN 20-JUL 03, 2010

Conference Location: Sinaia, ROMANIA

Conference Sponsors: Abdus Salam Int Ctr Theoret Phys, Natl Author Sci Res, Horia Hulubei Natl Inst Phys & Nucl Engn, Texas A&M Univ, Cyclotron Inst, Central European Initiat

FOREGROUNDS CONTAMINATION IN CMB POLARIZATION DATA: IMPLICATIONS FOR CMB B-MODE POLARIZATION MEASUREMENTS WITH PLANCK

2009

Author(s): Stefanescu, P (Stefanescu, P.); Popa, LA (Popa, L. A.); Vasile, A (Vasile, A.)

Source: ROMANIAN REPORTS IN PHYSICS  Volume: 61  Issue: 3  Pages: 523-530  Published Date: 2009   

Abstract: We analyze the possibility of detection of the Cosmic Microwave Background (CMB) B-mode polarization by the Planck experiment for the ACDM cosmological model with tensor contribution to primordial perturbation given by currently favored ratio of tensor to scalar perturbations, 0.016 < r < 0.16. The cosmological B-mode polarization is compared with models for the systematic noise induced by the galactic and extragalactic foregrounds in the Planck polarization channels. We have obtained that the 70 GHz channel have the lowest foregrounds induced noise level and, for the considered class of cosmological models, can detect the cosmological B-mode polarization at 3 sigma level for a tensor to scalar ratio r > 0.08. For greater tensor contributions, also the l 00 GHz, 143 GHz and 44 GHz channels will be able to detect the CMB B-mode polarization.

This work has been done on behalf of the Planck-LFI activities.

Accession Number: WOS:000271172200017

CONSTRAINTS ON THE LEPTON ASYMMETRY AND RADIATION ENERGY DENSITY: IMPLICATIONS FOR PLANCK

2009

Author(s): Popa, LA (Popa, L. A.); Stefanescu, P (Stefanescu, P.); Vasile, A (Vasile, A.)

Source: ROMANIAN REPORTS IN PHYSICS  Volume: 61  Issue: 3  Pages: 531-545  Published Date: 2009   

Abstract: By using most of the present Cosmic Microwave Background (CMB) and Large Scale Structure (LSS) measurements and the Big Bang Nucleosynthesis (BBN) constraints on the primordial helium abundance, Y-p, we set bounds on the radiation content of the Universe and neutrino properties. We consider lepton asymmetric cosmological models and we find that present CMB and LSS data constraint the neutrino degeneracy parameter at xi(v) (and consequently the lepton asymmetry of the neutrino background L-v), Delta N-oth(eff) the variation of the relativistic degrees of freedom due to possible other physical processes that occurred between BBN and structure formation epoch, the contribution to the effective number of relativistic neutrino species Delta N-eff and Y-p (2-sigma errors), better than older datasets or CMB data alone and the standard value of Y-p 0.24, relaxing the stringent BBN constraint on the neutrino degeneracy parameter.

We forecast that the CMB temperature and polarization maps observed with high angular resolutions and sensitivity by the future Planck Mission will constraint Y-p in agreement with its most stringent limits given by the BBN and also the neutrino degeneracy parameter, not excluding the possibility of larger lepton asymmetry. This work has been done on behalf of Planck-LFI activities.

Accession Number: WOS:000271172200018

WMAP five-year constraints on lepton asymmetry and radiation energy density: implications for PLANCK

2008

Author(s): Popa, LA (Popa, L. A.); Vasile, A (Vasile, A.)

Source: JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS  Issue: 6  Article Number: 028  DOI: 10.1088/1475-7516/2008/06/028  Published Date: 2008 JUN  

Abstract: In this paper we set bounds on the radiation content of the Universe and neutrino properties by using the WMAP ( Wilkinson microwave anisotropy probe) five-year CMB ( cosmic microwave background) measurements complemented with most of the existing CMB and LSS ( large scale structure) data ( WMAP5 + All), imposing also self-consistent BBN ( big bang nucleosynthesis) constraints on the primordial helium abundance.

We consider lepton asymmetric cosmological models parametrized by the neutrino degeneracy parameter xi(nu) and the variation of the relativistic degrees of freedom, Delta N-eff(oth), due to possible other physical processes occurring between BBN and structure formation epochs.

We get a mean value of the effective number of relativistic neutrino species of N-eff = 2.98 (2.27) (3.60) (1.65) (4.37), providing an important improvement over the similar result obtained from WMAP5 + BAO + SN + HST ( BAO: baryonic acoustic oscillations; SN: supernovae; HST: Hubble Space Telescope) data ( Komatsu et al ( WMAP Collaboration), 2008 Astrophys. J. Suppl. submitted [ 0803.0547]). We also find a strong correlation between Omega(m)h(2) and z(eq), showing that we observe Ne. mainly via the effect of zeq, rather than via neutrino anisotropic stress as claimed by the WMAP team ( Komatsu et al ( WMAP Collaboration), 2008 Astrophys. J. Suppl. submitted [ 0803.0547]).

WMAP5 + All data provide a strong bound on the helium mass fraction of Y-p = 0.2486 +/- 0.0085 ( 68% CL), that rivals the bound on Y-p obtained from the conservative analysis of the present data on helium abundance.

For the neutrino degeneracy parameter we. nd a bound of -0.216 <= xi(nu) <= 0.226 ( 68% CL), which represents an important improvement over the similar result obtained by using the WMAP three-year data.

The inclusion in the analysis of LSS data reduces the upper limit of the neutrino mass to m(nu) < 0.46 eV ( 95% CL) with respect to the values obtained from the analysis from WMAP5-only data ( Dunkley et al ( WMAP Collaboration), 2008 Astrophys. J. Suppl. submitted [ 0803.0586]) and WMAP5 + BAO + SN + HST data ( Komatsu et al ( WMAP Collaboration), 2008 Astrophys. J. Suppl. submitted [ 0803.0547]).

We forecast that the CMB temperature and polarization measurements observed with high angular resolutions and sensitivities by the future Planck satellite will reduce the errors on xi(nu) and Y-p down to sigma(xi(nu)) similar or equal to 0.089 ( 68% CL) and sigma( Y-p) = 0.013 ( 68% CL) respectively, values fully consistent with the BBN bounds on these parameters.

This work has been done on behalf of Planck-LFI ( low frequency instrument) activities.

Accession Number: WOS:000257339800006