Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background
AffiliationUniv Arizona, Dept Phys, Appl Math Program
Univ Arizona, Dept Astron
Keywordscosmic background radiation
large-scale structure of Universe
MetadataShow full item record
PublisherEDP SCIENCES S A
CitationMelia, F., & Lopez-Corredoira, M. (2018). Evidence of a truncated spectrum in the angular correlation function of the cosmic microwave background. Astronomy & Astrophysics, 610, A87.
JournalASTRONOMY & ASTROPHYSICS
Rights© ESO, 2018.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractAim. The lack of large-angle correlations in the fluctuations of the cosmic microwave background (CMB) conflicts with predictions of slow-roll inflation. But while probabilities (≲0.24%) for the missing correlations disfavour the conventional picture at ≳3σ, factors not associated with the model itself may be contributing to the tension. Here we aim to show that the absence of large-angle correlations is best explained with the introduction of a non-zero minimum wave number kmin for the fluctuation power spectrum P(k). Methods. We assumed that quantum fluctuations were generated in the early Universe with a well-defined power spectrum P(k), although with a cut-off kmin ≠ 0. We then re-calculated the angular correlation function of the CMB and compared it with Planck observations. Results. The Planck 2013 data rule out a zero kmin at a confidence level exceeding 8σ. Whereas purely slow-roll inflation would have stretched all fluctuations beyond the horizon, producing a P(k) with kmin = 0 – and therefore strong correlations at all angles – a kmin ≠ 0 would signal the presence of a maximum wavelength at the time (tdec) of decoupling. This argues against the basic inflationary paradigm, and perhaps even suggests non-inflationary alternatives, for the origin and growth of perturbations in the early Universe. In at least one competing cosmology, the Rh = ct universe, the inferred kmin corresponds to the gravitational radius at tdec.
NoteOpen access journal
VersionFinal accepted manuscript