Search Publications
Search for astrophysical rotating Ellis wormholes with x-ray reflection spectroscopy
Bambi, Cosimo; Zhou, Menglei; Cardenas-Avendano, Alejandro +2 more
Recently, two of us have found numerically rotating Ellis wormholes as solutions of four-dimensional Einstein gravity coupled to a phantom field. In this paper, we investigate possible observational signatures to identify similar objects in the Universe. These symmetric wormholes have a mass and are compact, so they may look like black holes. We s…
Kinematic Sunyaev-Zel'dovich effect with projected fields. II. Prospects, challenges, and comparison with simulations
Spergel, David N.; Ferraro, Simone; Hill, J. Colin +2 more
The kinematic Sunyaev-Zel'dovich (kSZ) signal is a powerful probe of the cosmic baryon distribution. The kSZ signal is proportional to the integrated free electron momentum rather than the electron pressure (which sources the thermal SZ signal). Since velocities should be unbiased on large scales, the kSZ signal is an unbiased tracer of the large-…
Cosmological hints of modified gravity?
Di Valentino, Eleonora; Melchiorri, Alessandro; Silk, Joseph
The recent measurements of cosmic microwave background (CMB) temperature and polarization anisotropies made by the Planck satellite have provided impressive confirmation of the Λ CDM cosmological model. However interesting hints of slight deviations from Λ CDM have been found, including a 95% C.L. preference for a "modified gravity" (MG) structure…
Cosmological limits on neutrino unknowns versus low redshift priors
Di Valentino, Eleonora; Melchiorri, Alessandro; Mena, Olga +2 more
Recent cosmic microwave background (CMB) temperature and polarization anisotropy measurements from the Planck mission have significantly improved previous constraints on the neutrino masses as well as the bounds on extended models with massless or massive sterile neutrino states. However, due to parameter degeneracies, additional low redshift prio…
Updated constraints and forecasts on primordial tensor modes
Melchiorri, Alessandro; Cabass, Giovanni; Gerbino, Martina +3 more
We present new, tight, constraints on the cosmological background of gravitational waves (GWs) using the latest measurements of CMB temperature and polarization anisotropies provided by the Planck, BICEP2 and Keck Array experiments. These constraints are further improved when the GW contribution NeffGW to the effective number…
Dark matter component decaying after recombination: Lensing constraints with Planck data
Chudaykin, A.; Gorbunov, D.; Tkachev, I.
It has been recently suggested [Z. Berezhiani, A. D. Dolgov, and I. I. Tkachev, Phys. Rev. D 92, 061303 (2015)] that emerging tension between cosmological parameter values derived in high-redshift (CMB anisotropy) and low-redshift (cluster counts, Hubble constant) measurements can be reconciled in a model which contains a subdominant fraction of d…
Impacts of dark energy on weighing neutrinos: Mass hierarchies considered
Zhang, Xin; Wang, Sai; Wang, Yi-Fan +1 more
Taking into account the mass splittings between three active neutrinos, we investigate the impacts of dark energy on constraining the total neutrino mass ∑mν by using recent cosmological observations. We consider two typical dark energy models, namely, the w CDM model and the holographic dark energy (HDE) model, which both have an addit…
Ruling out the light weakly interacting massive particle explanation of the Galactic 511 keV line
Vincent, Aaron C.; Wilkinson, Ryan J.; BÅ`hm, Céline +1 more
Over the past few decades, an anomalous 511 keV gamma-ray line has been observed from the center of the Milky Way. Dark matter (DM) in the form of light (≲10 MeV ) weakly interacting massive particles (WIMPs) annihilating into electron-positron pairs has been one of the leading hypotheses of the observed emission. Given the small required cross se…
Constraints on dark-matter properties from large-scale structure
Kunz, Martin; Nesseris, Savvas; Sawicki, Ignacy
We use large-scale cosmological observations to place constraints on the dark-matter pressure, sound speed and viscosity and infer a limit on the mass of warm-dark-matter particles. Measurements of the cosmic microwave background anisotropies constrain the equation of state and sound speed of the dark matter (DM) at last scattering at the per mill…
Forecasting performance of CMB experiments in the presence of complex foreground contaminations
Errard, Josquin; Stompor, Radek; Poletti, Davide
We present a new, semianalytic framework for estimating the level of residuals present in cosmic microwave background (CMB) maps derived from multifrequency CMB data and forecasting their impact on cosmological parameters. The data are assumed to contain non-negligible signals of astrophysical and/or Galactic origin, which we clean using a paramet…