Do joint CMB and HST data support a scale invariant spectrum?

Journal Article · Sat Apr 01 00:00:00 EDT 2017 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2017/04/003· OSTI ID:22679938

Benetti, Micol; Graef, Leila L.

We combine current measurements of the local expansion rate, H {sub 0}, and Big Bang Nucleosynthesis (BBN) estimates of helium abundance with the latest cosmic microwave background (CMB) data from the Planck Collaboration to discuss the observational viability of the scale invariant Harrison-Zeldovch-Peebles (HZP) spectrum. We also analyze some of its extensions, namely, HZP + Y {sub P} and HZP + N {sub eff}, where Y {sub P} is the primordial helium mass fraction and N {sub eff} is the effective number of relativistic degrees of freedom. We perform a Bayesian analysis and show that the latter model is favored with respect to the standard cosmology for values of N {sub eff} lying in the interval 3.70 ± 0.13 (1σ), which is currently allowed by some independent analyses.

• OSTI ID: 22679938
• Journal Information: Journal of Cosmology and Astroparticle Physics, Vol. 2017, Issue 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
COSMOLOGY
DEGREES OF FREEDOM
EXPANSION
MASS
NUCLEOSYNTHESIS
RELATIVISTIC RANGE
RELICT RADIATION
SPECTRA