ScholarLens Back to search
2006•Unpublished venueRequires access

Hints of Isocurvature Perturbations in the Cosmic Microwave Background

Reijo Keskitalo, H. Kurki‐Suonio, Vesa Muhonen, J. Väliviita

Open publisher page 28 citations

Abstract

Abstract. The improved data on the cosmic microwave background (CMB) anisotropy allow a better determination of the adiabaticity of the primordial perturbation. Interestingly, we find that recent CMB data seem to favor a contribution of a primordial isocurvature mode where the entropy perturbation is positively correlated with the primordial curvature perturbation and has a large spectral index (niso ∼ 3). With 4 additional parameters we obtain a better fit to the CMB data by ∆χ 2 = 9.7 compared to an adiabatic model. For this best-fit model the nonadiabatic contribution to the CMB temperature variance is 4%. According to a Markov Chain Monte Carlo analysis the nonadiabatic contribution is positive at more than 95 % C.L. The exact C.L. depends somewhat on the choice of priors, and we discuss the effect of different priors as well as additional cosmological data. PACS numbers: 98.70.Vc, 98.80.CqHints of Isocurvature Perturbations in the Cosmic Microwave Background? 2 1.

About this research paper

What this paper is about

Abstract. The improved data on the cosmic microwave background (CMB) anisotropy allow a better determination of the adiabaticity of the primordial perturbation. Interestingly, we find that recent CMB data seem to favor a contribution of a primordial isocurvature mode where the entropy perturbation is positively correlated with the primordial curvature perturbation and has a large spectral index (niso ∼ 3). With 4 additional parameters we obtain a better fit to the CMB data by ∆χ 2 = 9.7 compared to an adiabatic model. For this best-fit model the nonadiabatic contribution to the CMB temperature variance is 4%. According to a Markov Chain Monte Carlo analysis the nonadiabatic contribution is positive at more than 95 % C.L. The exact C.L. depends somewhat on the choice of priors, and we discuss the effect of different priors as well as additional cosmological data. PACS numbers: 98.70.Vc, 98.80.CqHints of Isocurvature Perturbations in the Cosmic Microwave Background? 2 1.

Why it matters

OpenAlex reports 28 citations for this work. Citation counts describe recorded attention and do not establish research quality.

Key contribution

A contribution statement is not available in the OpenAlex record.

Method / approach

Method details are not available in the OpenAlex metadata.

Main findings

Findings are not separately available in the OpenAlex metadata.

Limitations

Limitations are not available in the OpenAlex metadata.

Applications

Application details are not available in the OpenAlex metadata.

Available abstract

Abstract. The improved data on the cosmic microwave background (CMB) anisotropy allow a better determination of the adiabaticity of the primordial perturbation. Interestingly, we find that recent CMB data seem to favor a contribution of a primordial isocurvature mode where the entropy perturbation is positively correlated with the primordial curvature perturbation and has a large spectral index (niso ∼ 3). With 4 additional parameters we obtain a better fit to the CMB data by ∆χ 2 = 9.7 compared to an adiabatic model. For this best-fit model the nonadiabatic contribution to the CMB temperature variance is 4%. According to a Markov Chain Monte Carlo analysis the nonadiabatic contribution is positive at more than 95 % C.L. The exact C.L. depends somewhat on the choice of priors, and we discuss the effect of different priors as well as additional cosmological data. PACS numbers: 98.70.Vc, 98.80.CqHints of Isocurvature Perturbations in the Cosmic Microwave Background? 2 1.

Key concepts: Cosmic microwave background, Physics, Cosmic variance, Adiabatic process, Planck, Cosmic background radiation, Cosmological perturbation theory, Astrophysics

Related papers

Related paper 1Related paper 2Related paper 3
Back to paper searchBrowse research topicsOriginal source
Hints of Isocurvature Perturbations in the Cosmic Microwave Background — Research Paper | ScholarLens