Search Publications
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…
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…
Revisiting bounds on primordial black hole as dark matter with X-ray background
Tan, Xiu-Hui; Xia, Jun-Qing
Within the mass range of 1016 - 5 × 1018 g, primordial black holes (PBHs) persist as plausible candidates for dark matter. Our study involves a reassessment of the constraints on PBHs through a comparative analysis of the cosmic X-ray background (CXB) and the emissions arising from their Hawking evaporation. We identify previ…
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…
A pilot search for MeV gamma-ray emission from five galaxy clusters using archival COMPTEL data
Manna, Siddhant; Desai, Shantanu
We search for MeV gamma-ray emission between 0.75–30 MeV from five galaxy clusters, viz. Coma, VIRGO, SPT-CL J2012-5649, Bullet, and El Gordo, using archival data from the COMPTEL telescope. For this purpose we use three search templates: point source, radial disk and radial Gaussian. We do not detect any signals from Coma, SPT-CL J2012-5649, Bull…
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…