Search Publications
The trouble with H0
Riess, Adam G.; Verde, Licia; Bernal, José Luis
We perform a comprehensive cosmological study of the H0 tension between the direct local measurement and the model-dependent value inferred from the Cosmic Microwave Background. With the recent measurement of H0 this tension has raised to more than 3 σ. We consider changes in the early time physics without modifying the late …
Lyman-alpha forests cool warm dark matter
Palanque-Delabrouille, Nathalie; Viel, Matteo; Yèche, Christophe +2 more
The free-streaming of keV-scale particles impacts structure growth on scales that are probed by the Lyman-alpha forest of distant quasars. Using an unprecedentedly large sample of medium-resolution QSO spectra from the ninth data release of SDSS, along with a state-of-the-art set of hydrodynamical simulations to model the Lyman-alpha forest in the…
Evidence for dark matter interactions in cosmological precision data?
Lesgourgues, Julien; Marques-Tavares, Gustavo; Schmaltz, Martin
We study a two-parameter extension of the cosmological standard model ΛCDM in which cold dark matter interacts with a new form of dark radiation. The two parameters correspond to the energy density in the dark radiation fluid ΔNfluid and the interaction strength between dark matter and dark radiation. The interactions give rise to a ver…
Robust forecasts on fundamental physics from the foreground-obscured, gravitationally-lensed CMB polarization
Peiris, Hiranya V.; Feeney, Stephen M.; Errard, Josquin +1 more
Recent results from the BICEP, Keck Array and Planck Collaborations demonstrate that Galactic foregrounds are an unavoidable obstacle in the search for evidence of inflationary gravitational waves in the cosmic microwave background (CMB) polarization. Beyond the foregrounds, the effect of lensing by intervening large-scale structure further obscur…
Constraints on deviations from ΛCDM within Horndeski gravity
Verde, Licia; Jimenez, Raul; Cuesta, Antonio J. +1 more
Recent anomalies found in cosmological datasets such as the low multipoles of the Cosmic Microwave Background or the low redshift amplitude and growth of clustering measured by e.g., abundance of galaxy clusters and redshift space distortions in galaxy surveys, have motivated explorations of models beyond standard ΛCDM. Of particular interest are …
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…