Search Publications
Cosmology with massive neutrinos III: the halo mass function and an application to galaxy clusters
Viel, Matteo; Xia, Jun-Qing; Costanzi, Matteo +4 more
We use a suite of N-body simulations that incorporate massive neutrinos as an extra-set of particles to investigate their effect on the halo mass function. We show that for cosmologies with massive neutrinos the mass function of dark matter haloes selected using the spherical overdensity (SO) criterion is well reproduced by the fitting formula of …
Axion hot dark matter bounds after Planck
Mirizzi, Alessandro; Archidiacono, Maria; Hannestad, Steen +2 more
We use cosmological observations in the post-Planck era to derive limits on thermally produced cosmological axions. In the early universe such axions contribute to the radiation density and later to the hot dark matter fraction. We find an upper limit ma < 0.67 eV at 95% C.L. after marginalising over the unknown neutrino masses, usin…
Low & high scale MSSM inflation, gravitational waves and constraints from Planck
Choudhury, Sayantan; Mazumdar, Anupam; Pal, Supratik
In this paper we will analyze generic predictions of an inflection-point model of inflation with Hubble-induced corrections and study them in light of the Planck data. Typically inflection-point models of inflation can be embedded within Minimal Supersymmetric Standard Model (MSSM) where inflation can occur below the Planck scale. The flexibility …
Observational signatures of anisotropic inflationary models
Ohashi, Junko; Tsujikawa, Shinji; Soda, Jiro
We study observational signatures of two classes of anisotropic inflationary models in which an inflaton field couples to (i) a vector kinetic term FµνFµν and (ii) a two-form kinetic term HµνλHµνλ. We compute the corrections from the anisotropic sources to the power spectrum of gr…
The effect of dark matter and dark energy interactions on the peculiar velocity field and the kinetic Sunyaev-Zel'dovich effect
Wang, Bin; Xu, Xiao-Dong; Zhang, Pengjie +1 more
The interaction between Dark Matter and Dark Energy has been proposed as a mechanism to alleviate the coincidence problem. We analyze its effects on the evolution of the gravitational and the peculiar velocity fields. We find that for different model parameters peculiar velocities vary from a factor five times smaller to two times larger than in t…
Dark radiation sterile neutrino candidates after Planck data
Di Valentino, Eleonora; Melchiorri, Alessandro; Mena, Olga
Recent Cosmic Microwave Background (CMB) results from the Planck satellite, combined with previous CMB data and Hubble constant measurements from the Hubble Space Telescope, provide a constraint on the effective number of relativistic degrees of freedom 3.62+0.50-0.48 at 95% CL. New Planck data provide a unique opportunity to…
The small scale power asymmetry in the cosmic microwave background
Flender, Samuel; Hotchkiss, Shaun
We investigate the hemispherical power asymmetry in the cosmic microwave background on small angular scales. We find an anomalously high asymmetry in the multipole range l = 601-2048, with a naive statistical significance of 6.5σ. However, we show that this extreme anomaly is simply a coincidence of three other effects, relativistic power modulati…
Reconstruction of broad features in the primordial spectrum and inflaton potential from Planck
Hazra, Dhiraj Kumar; Smoot, George F.; Shafieloo, Arman
With the recently published Cosmic Microwave Background data from Planck we address the optimized binning of the primordial power spectrum. As an important modification to the usual binning of the primordial spectrum, along with the spectral amplitude of the bins, we allow the position of the bins also to vary. This technique enables us to address…
Mixed inflaton and spectator field models after Planck
Takahashi, Tomo; Enqvist, Kari
We investigate the possibility that the primordial perturbation has two sources: the inflaton and a spectator field, which is not dynamically important during inflation but which after inflation can contribute to the curvature perturbation. We derive the constraints on the model by using recent Planck results on the spectral index, tensor-to-scala…
(Lack of) Cosmological evidence for dark radiation after Planck
Peiris, Hiranya V.; Verde, Licia; Feeney, Stephen M. +1 more
We use Bayesian model comparison to determine whether extensions to Standard-Model neutrino physics — primarily additional effective numbers of neutrinos and/or massive neutrinos — are merited by the latest cosmological data. Given the significant advances in cosmic microwave background (CMB) observations represented by the Planck data, we examine…