601 talks across 60 sessions. Search by title, author or full text.
601 results
In this work, we study the properties of dissipative shocks for fully relativistic accretion flows around spinning black holes. In an accretion flow harbouring a dissipative shock (formally known as radiative shock), a significant portion of the thermal energy…
We consider repetitive decays in the ergosphere of an initially extreme Kerr BH and show that these processes are highly irreversible. For each decay, including the BH capture of the particle falling into the horizon, the increase of the irreducible mass is mu…
Type Ia Supernovae (SNe Ia) are considered the most reliable standard candles and they have played an invaluable role in cosmology since the discovery of the Universe’s accelerated expansion. During the last decades, the SNe Ia samples have been improved in nu…
The Λ-ColdDarkMatter model, despite being in well agreement with many observational datasets at the background level, exhibits a growth of perturbations troubled by some inconsistencies: the H0 and σ8 tensions. Adopting a theoretical perspective, this opens th…
; Juan Palacios González 6 ; Jérome De Favereau 7 ; Massimo Mastrodicasa 8 ; Mathieu Lamoureux 7 ; Sebastien Le Stum 3 ; Silvia Celli 9 ; Vincent Cecchini 6 1 INFN sezione di Roma1 2 Ruhr Universität, Bochum 3 Centre de Physique des Particules de Marseille 4 I…
INAF Napoli 5 INAF - OAS Bologna 6 Universita’ degli Studi di Ferrara 7 Department of Physics - University Federico II of Napoli The light curves (LCs) of long gamma-ray bursts (GRBs) show a wide variety of morphologies, which current LC simulation models base…
After more than two years of scanning the sky the eROSITA X-ray telescope aboard SRG orbital observatory produced the best ever X-ray maps of the sky and discovered more than three million X-ray sources, of which about 20% are stars with active coronas in the…
I will briefly summarize ongoing activities related to Strong Gravitational lensing, and illustrate a few very recent results of strong lensing events uncovered in the Euclid ERO data. The Euclid mission: current status, results from early observations, and fu…
The paleo-detector technique proposes to use long-age minerals, which have been exposed to an enormous flux of particles, as astroparticle detectors. Some of these particles should have interacted with mineral nuclei, generating linear defects in the crystalli…
The future space-borne gravitational wave(GW) missions will be able to detect abundant gravitational wave signals in the micro-Hz band. The gravitational wave mission, ASTROD-GW can bridge the gap between the millihertz and nanohertz bands and has a great pote…
The trace anomaly is the breaking of Weyl (∼ scale) invariance upon quantisation of a theory, and occurs in a gauge and/or gravitational background. The presence of the parity violating Pontryagin densities RR̃ and FF̃ in the trace anomaly could have far reach…
Inspired by the pioneering 1968 work of L Parker, demonstrating matter quanta production in a dynamical spacetime background, we consider production of scalar quanta in a gravitational wave background. Choosing the spacetime to be a flat spacetime perturbed li…
We investigate inflationary particle production, focusing in particular on the role of inflaton fluctuations and the corresponding geometric particle production arising from spacetime perturbations. We analyze both small and large-field models, in agreement wi…
Despite decades of research, cosmology still lacks reliable probes to study the Universe in the intermediate redshift regime (from z = 1 up to z = 1100). Very few astronomical objects observed at such high distances can be standardized. We present the case of…
The detection of the gravitational wave (GW) signal GW170817 and the electromagnetic (EM) signal AT2017gfo confirmed the association between binary neutron star (BNS) mergers and kilonovae (KNe) and showed the potential of joint detection to unveil the nature…
The Newtonian law of non-relativistic gravity has been tested in many laboratory experiments with very high precision. In contrast, the gravitational field of ultra-relativistic matter, dominated by kinetic energy and stresses, has not been measured directly.…
Solutions of the usual wave equation involve two arbitrary constants since it is a linear second order ordinary differential equation. Physically, these constants represent the amplitude and frequency of the waves. It is not a priori clear that “nonlinear wave…
Neutrinos can be used to probe a vast number of physics phenomena, as in the case of searches for dark matter candidates in astrophysical objects. Dark matter particles can accumulate in massive astrophysical bodies and annihilate into Standard Model particles…
GRB afterglows are powered by emission from relativistic collisionless shocks. The converter acceleration mechanism, which is specific just for relativistic shocks, makes them efficient emitters and at the same time modifies the shock structure. As a result, t…
KM3NeT is a multi-site underwater detector, designed to detect and study cosmic neutrinos and their sources in the Universe, and improve the measurement of the neutrino oscillation parameters. Two neutrino telescopes are under construction in the Mediterranean…
I review the phenomenology of Planck-scale effects influencing the propagation of high-energy particles from astrophysical sources. I discuss the interplay between Planck-scale effects and the universe expansion, and present possible methods to constrain such…
Quantum gravity has yet remained elusive from an observational standpoint. In this talk, I will discuss Swerves, a proposal within quantum gravity phenomenology that predicts testable effects in cosmological data. Motivated by considerations in Causal Set Theo…
Quantum gravity has yet remained elusive from an observational standpoint. In this talk, I will discuss Swerves, a proposal within quantum gravity phenomenology that predicts testable effects in cosmological data. Motivated by considerations in Causal Set Theo…
The propagation of electromagnetic waves in vacuum is commonly modeled within the geometric optics approximation according to which light rays follow null geodesics. This is a sensible model whenever the wavelength is much smaller than the characteristic lengt…
We study the linear polarization from the accretion disk around horizonless compact objects. Previous works have shown that these spacetimes can have significantly different lensing properties from black holes. In particular, their relativistic images can exib…