Search Publications
Constraining primordial non-Gaussianity from DESI quasar targets and Planck CMB lensing
Miquel, Ramon; Font-Ribera, Andreu; Yèche, Christophe +33 more
We detect the cross-correlation between 2.7 million DESI quasar targets across 14,700 deg2 (180 quasars deg-2) and Planck 2018 CMB lensing at ∼30σ. We use the cross-correlation on very large scales to constrain local primordial non-Gaussianity via the scale dependence of quasar bias. The DESI quasar targets lie at an effectiv…
Dissecting the stochastic gravitational wave background with astrometry
Dai, Liang; Xue, Xiao; Çalışkan, Mesut +3 more
Astrometry, the precise measurement of star motions, offers an alternative avenue to investigate low-frequency gravitational waves through the spatial deflection of photons, complementing pulsar timing arrays reliant on timing residuals. Upcoming data from Gaia, Theia, and Roman can not only cross-check pulsar timing array findings but also explor…
Growth history and quasar bias evolution at z < 3 from Quaia
Alonso, David; Carron, Julien; Lewis, Antony +4 more
We make use of the Gaia-unWISE quasar catalogue, Quaia, to constrain the growth history out to high redshifts from the clustering of quasars and their cross-correlation with maps of the Cosmic Microwave Background (CMB) lensing convergence. Considering three tomographic bins, centred at redshifts z̅i = [0.69, 1.59, 2.72], we reconstruct …
Simulation-based inference of deep fields: galaxy population model and redshift distributions
Tortorelli, Luca; Refregier, Alexandre; Kacprzak, Tomasz +3 more
Accurate redshift calibration is required to obtain unbiased cosmological information from large-scale galaxy surveys. In a forward modelling approach, the redshift distribution n(z) of a galaxy sample is measured using a parametric galaxy population model constrained by observations. We use a model that captures the redshift evolution of the gala…
Hubble tension in a nonminimally coupled curvature-matter gravity model
Bertolami, Orfeu; Barroso Varela, Miguel
The presently open problem of the Hubble tension is shown to be removed in the context of a modified theory of gravity with a non-minimal coupling between curvature and matter. By evolving the cosmological parameters that match the cosmic microwave background data until their values from direct late-time measurements, we obtain an agreement betwee…
Gamma rays from dark matter spikes in EAGLE simulations
Peletier, R. F.; Horns, D.; Moulin, E. +3 more
Intermediate Mass Black Holes (IMBHs) with a mass range between 100 M⊙ and 106 M⊙ are expected to be surrounded by high dark matter densities, so-called dark matter spikes. The high density of self-annihilating Weakly Interacting Massive Particles (WIMPs) in these spikes leads to copious gamma-ray production. Suffi…
Observing gravitational waves with solar system astrometry
Mentasti, G.; Contaldi, C. R.
The subtle influence of gravitational waves on the apparent positioning of celestial bodies offers novel observational windows [1,2,3,4]. We calculate the expected astrometric signal induced by an isotropic Stochastic Gravitational Wave Background (SGWB) in the short distance limit. Our focus is on the resultant proper motion of Solar System objec…
Results of the follow-up of ANTARES neutrino alerts
Cenko, S. B.; André, M.; Chaty, S. +188 more
High-energy neutrinos could be produced in the interaction of charged cosmic rays with matter or radiation surrounding astrophysical sources. To look for transient sources associated with neutrino emission, a follow-up program of neutrino alerts has been operating within the ANTARES collaboration since 2009. This program, named TAToO, has triggere…
Wide binaries and modified gravity (MOG)
Moffat, J. W.
Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field G = GN (1+α), where GN is Newton's constant, and the massive (spin-1 graviton) vector field ϕµ . The wide binaries have …