Search for features in the spectrum of primordial perturbations using Planck and other datasets
Abstract
We reconstruct the power spectrum of primordial curvature perturbations by applying a well-validated non-parametric technique employing Tikhonov regularisation to the first data release from the Planck satellite. To improve the reconstruction on small spatial scales we include data from the ground-based ACT and SPT experiments, the WiggleZ galaxy redshift survey, the CFHTLenS tomographic weak lensing survey, and spectral analysis of the Lyman-α forest. The reconstructed scalar spectrum (assuming the standard ΛCDM cosmology) is not scale-free but has an infrared cutoff at k ≲ 5 × 10-4 Mpc-1 and several (2-3)σ features, of which two at wavenumber k/Mpc-1 0.0018 and 0.057 had been seen already in WMAP data. A higher significance feature at k ~ 0.12 Mpc-1 is indicated by Planck data, but may be sensitive to the systematic uncertainty around multipole ℓ ~ 1800 in the 217×217 GHz cross-spectrum. In any case accounting for the 'look elsewhere' effect decreases its global significance to ~2σ.
- Publication:
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Journal of Cosmology and Astroparticle Physics
- Pub Date:
- December 2015
- DOI:
- 10.1088/1475-7516/2015/12/052
- arXiv:
- arXiv:1510.03338
- Bibcode:
- 2015JCAP...12..052H
- Keywords:
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- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 35 pages, 18 figures