CosmoCoffee Forum Index CosmoCoffee

 FAQFAQ   SearchSearch  MemberlistSmartFeed   MemberlistMemberlist    RegisterRegister 
   ProfileProfile   Log inLog in 
Arxiv New Filter | Bookmarks & clubs | Arxiv ref/author:

[0804.2971] WMAP 5-year constraints on lepton asymmetry and radiation energy density: Implications for Planck
Authors:L.A. Popa, A. Vasile (Institute for Spaces Sciences, Bucharest)
Abstract:In this paper we set bounds on the radiation content of the Universe and neutrino properties by using the WMAP-5 year CMB measurements complemented with most of the existing CMB and LSS data (WMAP5+All),imposing also self-consistent BBN constraints on the primordial helium abundance. We consider lepton asymmetric cosmological models parametrized by the neutrino degeneracy parameter and the variation of the relativistic degrees of freedom, due to possible other physical processes occurred between BBN and structure formation epochs. We find that WMAP5+All data provides strong bounds on helium mass fraction and neutrino degeneracy parameter that rivals the similar bounds obtained from the conservative analysis of the present data on helium abundance. We also find a strong correlation between the matter energy density and the redshift of matter-radiation equality, z_re, showing that we observe non-zero equivalent number of relativistic neutrinos mainly via the change of the of z_re, rather than via neutrino anisotropic stress claimed by the WMAP team. 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 these parameters down to values fully consistent with the BBN bounds.
[PDF] [PS] [BibTex] [Bookmark]

Post new topic   Reply to topic    CosmoCoffee Forum Index -> arXiv papers
View previous topic :: View next topic  
Author Message
Vimal Simha

Joined: 11 May 2006
Posts: 13
Affiliation: Ohio State University

PostPosted: April 26 2008  Reply with quote

Their error bars on all cosmological parameters (table 3) while using the WMAP−5yr data seem much smaller than those reported by the WMAP team (Dunkley et al. and Komatsu et al.).

They also contest the WMAP team's claim to have detected neutrino anisotropic stress.
Back to top
View user's profile  
Display posts from previous:   
Post new topic   Reply to topic    CosmoCoffee Forum Index -> arXiv papers All times are GMT + 5 Hours
Page 1 of 1

Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB © 2001, 2005 phpBB Group. Sponsored by WordWeb online dictionary and dictionary software.