Search Publications
Constraining the time evolution of dark energy, curvature and neutrino properties with cosmic chronometers
Verde, Licia; Jimenez, Raul; Thomas, Daniel +4 more
We use the latest compilation of observational Hubble parameter measurements estimated with the differential evolution of cosmic chronometers, in the redshift range 0<z<2, to place constraints on cosmological parameters. We used a Markov-Chain Monte-Carlo approach to sample the parameter space for the cosmic chronometers dataset alone and in…
Cosmology and the neutrino mass ordering
Hannestad, Steen; Schwetz, Thomas
We propose a simple method to quantify a possible exclusion of the inverted neutrino mass ordering from cosmological bounds on the sum of the neutrino masses. The method is based on Bayesian inference and allows for a calculation of the posterior odds of normal versus inverted ordering. We apply the method for a specific set of current data from P…
Cosmological constraints on decoupled dark photons and dark Higgs
Berger, Joshua; Jedamzik, Karsten; Walker, Devin G. E.
Any neutral boson such as a dark photon or dark Higgs that is part of a non-standard sector of particles can mix with its standard model counterpart. When very weakly mixed with the Standard Model, these particles are produced in the early Universe via the freeze-in mechanism and subsequently decay back to standard model particles. In this work, w…
Cosmological constraints on coupled dark energy
Yang, Weiqiang; Wu, Yabo; Lu, Jianbo +1 more
The coupled dark energy model provides a possible approach to mitigate the coincidence problem of cosmological standard model. Here, the coupling term is assumed as bar Q = 3Hξxbar rhox, which is related to the interaction rate and energy density of dark energy. We derive the background and perturbation evolution equations fo…
Non-local gravity and comparison with observational datasets. II. Updated results and Bayesian model comparison with ΛCDM
Kunz, Martin; Pettorino, Valeria; Dirian, Yves +2 more
We present a comprehensive and updated comparison with cosmological observations of two non-local modifications of gravity previously introduced by our group, the so called RR and RT models. We implement the background evolution and the cosmological perturbations of the models in a modified Boltzmann code, using CLASS. We then test the non-local m…
Constraints on modified gravity from Planck 2015: when the health of your theory makes the difference
Salvatelli, Valentina; Marinoni, Christian; Piazza, Federico
We use the effective field theory of dark energy (EFT of DE) formalism to constrain dark energy models belonging to the Horndeski class with the recent Planck 2015 CMB data. The space of theories is spanned by a certain number of parameters determining the linear cosmological perturbations, while the expansion history is set to that of a standard …
Weak-lensing mass calibration of the Atacama Cosmology Telescope equatorial Sunyaev-Zeldovich cluster sample with the Canada-France-Hawaii telescope stripe 82 survey
Bond, J. R.; Calabrese, E.; Huffenberger, K. M. +39 more
Mass calibration uncertainty is the largest systematic effect for using clusters of galaxies to constrain cosmological parameters. We present weak lensing mass measurements from the Canada-France-Hawaii Telescope Stripe 82 Survey for galaxy clusters selected through their high signal-to-noise thermal Sunyaev-Zeldovich (tSZ) signal measured with th…
Primordial features and Planck polarization
Starobinsky, Alexei A.; Hazra, Dhiraj Kumar; Smoot, George F. +1 more
With the Planck 2015 Cosmic Microwave Background (CMB) temperature and polarization data, we search for possible features in the primordial power spectrum (PPS). We revisit the Wiggly Whipped Inflation (WWI) framework and demonstrate how generation of some particular primordial features can improve the fit to Planck data. WWI potential allows the …
Another look at distortions of the Cosmic Microwave Background spectrum
Negrello, M.; Lapi, A.; De Zotti, G. +2 more
We review aspects of Cosmic Microwave Background (CMB) spectral distortions which do not appear to have been fully explored in the literature. In particular, implications of recent evidences of heating of the intergalactic medium (IGM) by feedback from active galactic nuclei are investigated. Taking also into account the IGM heating associated to …
Differential cosmic expansion and the Hubble flow anisotropy
Wiltshire, David L.; Bolejko, Krzysztof; Nazer, M. Ahsan
The Universe on scales 01-100 h-1Mpc is dominated by a cosmic web of voids, filaments, sheets and knots of galaxy clusters. These structures participate differently in the global expansion of the Universe: from non-expanding clusters to the above average expansion rate of voids. In this paper we characterize Hubble expansion anisotropie…