Search Publications
Negative cosmological constant in the dark energy sector: tests from JWST photometric and spectroscopic observations of high-redshift galaxies
Menci, Nicola; Sen, Anjan A.; Vagnozzi, Sunny +2 more
Early observations with the James Webb Space Telescope (JWST) have revealed the existence of an unexpectedly large abundance of extremely massive galaxies at redshifts z ≳ 5: these are in tension with the predictions not only of the standard ΛCDM cosmology, but also with those of a wide class of dynamical dark energy (DE) models, and are generally…
A double take on early and interacting dark energy from JWST
Melchiorri, Alessandro; Mena, Olga; Nunes, Rafael C. +4 more
The very first light captured by the James Webb Space Telescope (JWST) revealed a population of galaxies at very high redshifts more massive than expected in the canonical ΛCDM model of structure formation. Barring, among others, a systematic origin of the issue, in this paper, we test alternative cosmological perturbation histories. We argue that…
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…
21cm signal sensitivity to dark matter decay
Qin, Y.; Mesinger, A.; Facchinetti, G. +1 more
The redshifted 21cm signal from the Cosmic Dawn is expected to provide unprecedented insights into early Universe astrophysics and cosmology. Here we explore how dark matter can heat the intergalactic medium before the first galaxies, leaving a distinctive imprint in the 21cm power spectrum. We provide the first dedicated Fisher matrix forecasts o…
A hidden population of active galactic nuclei can explain the overabundance of luminous z > 10 objects observed by JWST
Furlanetto, Steven R.; Hegde, Sahil; Wyatt, Michael M.
The first wave of observations with JWST has revealed a striking overabundance of luminous galaxies at early times (z > 10) compared to models of galaxies calibrated to pre-JWST data. Early observations have also uncovered a large population of supermassive black holes (SMBHs) at z > 6. Because many of the high-z objects appear extended, the…
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…
Hard X-ray emission from blazars associated with high-energy neutrinos
Lutovinov, A. A.; Starobinsky, A. A.; Burenin, R. A. +4 more
Bright blazars were found to be prominent neutrino sources, and a number of IceCube events were associated with them. Evaluating high-energy photon emission of such blazars is crucial for better understanding of the processes and regions where neutrinos are produced. Here, we focus on hard X-ray emission observed by the SRG/ART-XC telescope, by th…
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…