Dark Radiation after Planck

• Main Authors: Said, Najla, Di Valentino, Eleonora, Gerbino, Martina
• Format: Text
• Language: unknown
• Published: arXiv 2013
• Subjects: Cosmology and Nongalactic Astrophysics astro-ph.CO; General Relativity and Quantum Cosmology gr-qc; High Energy Physics - Phenomenology hep-ph; High Energy Physics - Theory hep-th; FOS Physical sciences; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.1304.6217; https://arxiv.org/abs/1304.6217

We present new constraints on the relativistic neutrino effective number N_eff and on the Cosmic Microwave Background power spectrum lensing amplitude A_L from the recent Planck 2013 data release. Including observations of the CMB large angular scale polarization from the WMAP satellite, we obtain the bounds N_eff = 3.71 +/- 0.40 and A_L = 1.25 +/- 0.13 at 68% c.l.. The Planck dataset alone is therefore suggesting the presence of a dark radiation component at 91.1% c.l. and hinting for a higher power spectrum lensing amplitude at 94.3% c.l.. We discuss the agreement of these results with the previous constraints obtained from the Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT). Considering the constraints on the cosmological parameters, we found a very good agreement with the previous WMAP+SPT analysis but a tension with the WMAP+ACT results, with the only exception of the lensing amplitude. : 5 pages, 6 figures, 2 tables