0000000000697178
AUTHOR
Sunny Vagnozzi
showing 11 related works from this author
Constraints on the sum of the neutrino masses in dynamical dark energy models with $w(z) \geq -1$ are tighter than those obtained in $\Lambda$CDM
2018
We explore cosmological constraints on the sum of the three active neutrino masses $M_{\nu}$ in the context of dynamical dark energy (DDE) models with equation of state (EoS) parametrized as a function of redshift $z$ by $w(z)=w_0+w_a\,z/(1+z)$, and satisfying $w(z)\geq-1$ for all $z$. We perform a Bayesian analysis and show that, within these models, the bounds on $M_{\nu}$ \textit{do not degrade} with respect to those obtained in the $\Lambda$CDM case; in fact the bounds are slightly tighter, despite the enlarged parameter space. We explain our results based on the observation that, for fixed choices of $w_0\,,w_a$ such that $w(z)\geq-1$ (but not $w=-1$ for all $z$), the upper limit on $M…
Impact of neutrino properties on the estimation of inflationary parameters from current and future observations
2016
We study the impact of assumptions about neutrino properties on the estimation of inflationary parameters from cosmological data, with a specific focus on the allowed contours in the $n_s/r$ plane. We study the following neutrino properties: (i) the total neutrino mass $ M_\nu =\sum_i m_i$; (ii) the number of relativistic degrees of freedom $N_{eff}$; and (iii) the neutrino hierarchy: whereas previous literature assumed 3 degenerate neutrino masses or two massless neutrino species (that do not match neutrino oscillation data), we study the cases of normal and inverted hierarchy. Our basic result is that these three neutrino properties induce $< 1 \sigma$ shift of the probability contours in…
Nonminimal dark sector physics and cosmological tensions
2019
We explore whether non-standard dark sector physics might be required to solve the existing cosmological tensions. The properties we consider in combination are an interaction between the dark matter and dark energy components, and a dark energy equation of state $w$ different from that of the canonical cosmological constant $w=-1$. In principle, these two parameters are independent. In practice, to avoid early-time, superhorizon instabilities, their allowed parameter spaces are correlated. We analyze three classes of extended interacting dark energy models in light of the 2019 Planck CMB results and Cepheid-calibrated local distance ladder $H_0$ measurements of Riess et al. (R19), as well …
Soundness of Dark Energy properties
2020
Type Ia Supernovae (SNeIa) used as standardizable candles have been instrumental in the discovery of cosmic acceleration, usually attributed to some form of dark energy (DE). Recent studies have raised the issue of whether intrinsic SNeIa luminosities might evolve with redshift. While the evidence for cosmic acceleration is robust to this possible systematic, the question remains of how much the latter can affect the inferred properties of the DE component responsible for cosmic acceleration. This is the question we address in this work. We use SNeIa distance moduli measurements from the Pantheon and JLA samples. We consider models where the DE equation of state is a free parameter, either …
Do we have any hope of detecting scattering between dark energy and baryons through cosmology?
2020
We consider the possibility that dark energy and baryons might scatter off each other. The type of interaction we consider leads to a pure momentum exchange, and does not affect the background evolution of the expansion history. We parametrize this interaction in an effective way at the level of Boltzmann equations. We compute the effect of dark energy-baryon scattering on cosmological observables, focusing on the Cosmic Microwave Background (CMB) temperature anisotropy power spectrum and the matter power spectrum. Surprisingly, we find that even huge dark energy-baryon cross-sections $\sigma_{xb} \sim {\cal O}({\rm b})$, which are generically excluded by non-cosmological probes such as col…
Unveiling ν secrets with cosmological data: Neutrino masses and mass hierarchy
2017
Using some of the latest cosmological datasets publicly available, we derive the strongest bounds in the literature on the sum of the three active neutrino masses, $M_\nu$, within the assumption of a background flat $\Lambda$CDM cosmology. In the most conservative scheme, combining Planck cosmic microwave background (CMB) temperature anisotropies and baryon acoustic oscillations (BAO) data, as well as the up-to-date constraint on the optical depth to reionization ($\tau$), the tightest $95\%$ confidence level (C.L.) upper bound we find is $M_\nu0.06\,{\rm eV}$ from oscillations data would raise the quoted upper bounds by ${\cal O}(0.1\sigma)$ and would not affect our conclusions.
The galaxy power spectrum take on spatial curvature and cosmic concordance
2020
The concordance of the $\Lambda$CDM cosmological model in light of current observations has been the subject of an intense debate in recent months. The 2018 Planck Cosmic Microwave Background (CMB) temperature anisotropy power spectrum measurements appear at face value to favour a spatially closed Universe with curvature parameter $\Omega_K<0$. This preference disappears if Baryon Acoustic Oscillation (BAO) measurements are combined with Planck data to break the geometrical degeneracy, although the reliability of this combination has been questioned due to the strong tension present between the two datasets when assuming a curved Universe. Here, we approach this issue from yet another point…
Bounds on light sterile neutrino mass and mixing from cosmology and laboratory searches
2020
We provide a consistent framework to set limits on properties of light sterile neutrinos coupled to all three active neutrinos using a combination of the latest cosmological data and terrestrial measurements from oscillations, $\beta$-decay and neutrinoless double-$\beta$ decay ($0\nu\beta\beta$) experiments. We directly constrain the full $3+1$ active-sterile mixing matrix elements $|U_{\alpha4}|^2$, with $\alpha \in ( e,\mu ,\tau )$, and the mass-squared splitting $\Delta m^2_{41} \equiv m_4^2-m_1^2$. We find that results for a $3+1$ case differ from previously studied $1+1$ scenarios where the sterile is only coupled to one of the neutrinos, which is largely explained by parameter space …
On the improvement of cosmological neutrino mass bounds
2016
The most recent measurements of the temperature and low-multipole polarization anisotropies of the Cosmic Microwave Background (CMB) from the Planck satellite, when combined with galaxy clustering data from the Baryon Oscillation Spectroscopic Survey (BOSS) in the form of the full shape of the power spectrum, and with Baryon Acoustic Oscillation measurements, provide a $95\%$ confidence level (CL) upper bound on the sum of the three active neutrinos $\sum m _��< 0.183$ eV, among the tightest neutrino mass bounds in the literature, to date, when the same datasets are taken into account. This very same data combination is able to set, at $\sim70\%$ CL, an upper limit on $\sum m _��$ of $0.…
Improvement of cosmological neutrino mass bounds
2016
The most recent measurements of the temperature and low-multipole polarization anisotropies of the cosmic microwave background from the Planck satellite, when combined with galaxy clustering data f ...
Interacting dark energy in the early 2020s: a promising solution to the $H_0$ and cosmic shear tensions
2019
We examine interactions between dark matter and dark energy in light of the latest cosmological observations, focusing on a specific model with coupling proportional to the dark energy density. Our data includes Cosmic Microwave Background (CMB) measurements from the Planck 2018 legacy data release, late-time measurements of the expansion history from Baryon Acoustic Oscillations (BAO) and Supernovae Type Ia (SNeIa), galaxy clustering and cosmic shear measurements from the Dark Energy Survey Year 1 results, and the 2019 local distance ladder measurement of the Hubble constant $H_0$ from the Hubble Space Telescope. Considering Planck data both in combination with BAO or SNeIa data reduces th…