Search Publications
Iron Kα line of Kerr black holes with scalar hair
Bambi, Cosimo; Zhou, Menglei; Ni, Yueying +3 more
Recently, a family of hairy black holes in 4-dimensional Einstein gravity minimally coupled to a complex, massive scalar field was discovered [1]. Besides the mass M and spin angular momentum J, these objects are characterized by a Noether charge Q, measuring the amount of scalar hair, which is not associated to a Gauss law and cannot be measured …
Constraint on the abundance of primordial black holes in dark matter from Planck data
Huang, Qing-Guo; Wang, Ke; Chen, Lu
We use Planck data released in 2015 to constrain the abundance of primordial black holes (PBHs) in dark matter in two different reionization models (one is the instantaneous reionization and the other is the asymmetric reionization), and significantly improve the existing upper limits on the abundance of PBHs by around two orders of magnitude. The…
New CMB constraints for Abelian Higgs cosmic strings
Kunz, Martin; Lizarraga, Joanes; Urrestilla, Jon +2 more
We present cosmic microwave background (CMB) power spectra from recent numerical simulations of cosmic strings in the Abelian Higgs model and compare them to CMB power spectra measured by Planck. We obtain revised constraints on the cosmic string tension parameter Gµ. For example, in the ΛCDM model with the addition of strings and no primord…
Probing primordial features with future galaxy surveys
Finelli, F.; Moscardini, L.; Ballardini, M. +1 more
We study the capability of future measurements of the galaxy clustering power spectrum to probe departures from a power-law spectrum for primordial fluctuations. On considering the information from the galaxy clustering power spectrum up to quasi-linear scales, i.e. k < 0.1 h Mpc-1, we present forecasts for DESI, Euclid and SPHEREx i…
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 …