Search Publications
Planck limits on non-canonical generalizations of large-field inflation models
Stein, Nina K.; Kinney, William H.
In this paper, we consider two case examples of Dirac-Born-Infeld (DBI) generalizations of canonical large-field inflation models, characterized by a reduced sound speed, cS < 1. The reduced speed of sound lowers the tensor-scalar ratio, improving the fit of the models to the data, but increases the equilateral-mode non-Gaussianity, …
Constraining dynamical neutrino mass generation with cosmological data
Koksbang, S. M.; Hannestad, S.
We study models in which neutrino masses are generated dynamically at cosmologically late times. Our study is purely phenomenological and parameterized in terms of three effective parameters characterizing the redshift of mass generation, the width of the transition region, and the present day neutrino mass. We also study the possibility that neut…
Strongly coupled dark energy with warm dark matter vs. LCDM
Bonometto, S. A.; Mezzetti, M.; Mainini, R.
Cosmologies including strongly Coupled (SC) Dark Energy (DE) and Warm dark matter (SCDEW) are based on a conformally invariant (CI) attractor solution modifying the early radiative expansion. Then, aside of radiation, a kinetic field Φ and a DM component account for a stationary fraction, ~ 1 %, of the total energy. Most SCDEW predictions are hard…
Running vacuum cosmological models: linear scalar perturbations
Perico, E. L. D.; Tamayo, D. A.
In cosmology, phenomenologically motivated expressions for running vacuum are commonly parameterized as linear functions typically denoted by Λ(H2) or Λ(R). Such models assume an equation of state for the vacuum given by bar PΛ = - bar rhoΛ, relating its background pressure bar PΛ with its mean energy de…
H-ATLAS/GAMA: magnification bias tomography. Astrophysical constraints above ~1 arcmin
Ivison, R. J.; Bonavera, L.; Danese, L. +14 more
An unambiguous manifestation of the magnification bias is the cross-correlation between two source samples with non-overlapping redshift distributions. In this work we measure and study the cross-correlation signal between a foreground sample of GAMA galaxies with spectroscopic redshifts in the range 0.2<z<0.8, and a background sample of H-A…
A sensitive search for unknown spectral emission lines in the diffuse X-ray background with XMM-Newton
Schmitt, J. H. M. M.; Horns, D.; Gewering-Peine, A.
The Standard Model of particle physics can be extended to include sterile (right-handed) neutrinos or axions to solve the dark matter problem. Depending upon the mixing angle between active and sterile neutrinos, the latter have the possibility to decay into monoenergetic active neutrinos and photons in the keV-range while axions can couple to two…
Constraining the break of spatial diffeomorphism invariance with Planck data
Alcaniz, J. S.; Graef, L. L.; Benetti, M.
The current most accepted paradigm for the early universe cosmology, the inflationary scenario, shows a good agreement with the recent Cosmic Microwave Background (CMB) and polarization data. However, when the inflation consistency relation is relaxed, these observational data exclude a larger range of red tensor tilt values, prevailing the blue o…
Cosmological N-body simulations with generic hot dark matter
Brandbyge, Jacob; Hannestad, Steen
We have calculated the non-linear effects of generic fermionic and bosonic hot dark matter components in cosmological N-body simulations. For sub-eV masses, the non-linear power spectrum suppression caused by thermal free-streaming resembles the one seen for massive neutrinos, whereas for masses larger than 1 eV, the non-linear relative suppressio…
Integrated cosmological probes: concordance quantified
Amara, Adam; Refregier, Alexandre; Nicola, Andrina
Assessing the consistency of parameter constraints derived from different cosmological probes is an important way to test the validity of the underlying cosmological model. In an earlier work [1], we computed constraints on cosmological parameters for ΛCDM from an integrated analysis of CMB temperature anisotropies and CMB lensing from Planck, gal…
Thermal gravitational-wave background in the general pre-inflationary scenario
Xia, Jun-Qing; Wang, Kai; Santos, Larissa +1 more
We investigate the primordial gravitational waves (PGWs) in the general scenario where the inflation is preceded by a pre-inflationary stage with the effective equation of state w. Comparing with the results in the usual inflationary models, the power spectrum of PGWs is modified in two aspects: one is the mixture of the perturbation modes caused …