A5003447605- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Pulsars and Gravitational Waves Research
- Radio Astronomy Observations and Technology
- Cosmology and Gravitation Theories
- Galaxies: Formation, Evolution, Phenomena
- Relativity and Gravitational Theory
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Superconducting and THz Device Technology
- Black Holes and Theoretical Physics
- Quantum Mechanics and Applications
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Geophysics and Gravity Measurements
- Astro and Planetary Science
- Solar and Space Plasma Dynamics
- Philosophy and History of Science
- Particle Detector Development and Performance
- Ionosphere and magnetosphere dynamics
- Noncommutative and Quantum Gravity Theories
- Philosophy and Theoretical Science
Consejo Nacional de Investigaciones Científicas y Técnicas
2015-2024
Instituto Argentino de Radioastronomía
2015-2024
Universidad Nacional de La Plata
2015-2024
Agenzia Spaziale Italiana
2024
Friedrich-Alexander-Universität Erlangen-Nürnberg
2023
Comisión de Investigaciones Científicas
2019-2023
Hospital Geral de Bonsucesso
2023
Sapienza University of Rome
2018-2022
University of Buenos Aires
2019-2022
Istituto Nazionale di Fisica Nucleare, Sezione di Roma I
2022
In this paper we study the strong gravitational lensing scenario where lens is a Reissner-Nordstr\"om black hole. We obtain basic equations and show that, as in case of Schwarzschild hole, addition to primary secondary images, two infinite sets relativistic images are formed. find analytical expressions for positions amplifications images. The formalism applied low-mass hole placed at galactic halo.
The jets of microquasars with high-mass stellar companions are exposed to the dense matter field wind. We present estimates gamma-ray emission expected from jet-wind hadronic interaction and we discuss detectability phenomenon at high energies. proposed mechanism could explain some unidentified sources detected by EGRET instrument on galactic plane.
We present results of a search for optical microvariability in selected sample 23 southern AGNs, which includes both radio-quiet and radio-loud objects. Microvariations were clearly detected 60% the sources, with amplitudes from 2.2% up to 8% within single night. Night-to-night variability % was also observed BL Lac object 0537-441. On contrary, no rapid at all 8 quasars. have used data previously reported northern objects along our new AGNs order estimate duty cycles each class largest...
Context.LS I +61 303 is a puzzling Be/X-ray binary with variable gamma-ray emission up to TeV energies. The nature of the compact object and origin high-energy are unclear. One family models invokes particle acceleration in shocks from collision between B-star wind relativistic pulsar wind, whereas another centers on jet powered by accretion Be star decretion disc onto black hole. Recent high-resolution radio observations showing putative "cometary tail" pointing away near periastron have...
Observational and theoretical studies point to microquasars (MQs) as possible counterparts of a significant fraction the unidentifiedgamma-ray sources detected so far. At present, proper scenario explain emission beyond soft X-rays from these objects is not known, nor what precise connection between radio high-energy radiation. We develop new model where MQ jet dynamically dominated by cold protons radiatively relativistic leptons. The matter content power are both related with accretion...
Many of the astrophysical sources and violent phenomena observed in our Universe are potential emitters gravitational waves high-energy cosmic radiation, including photons, hadrons, presumably also neutrinos. Both (GW) neutrinos (HEN) messengers that may escape much denser media than photons. They travel unaffected over cosmological distances, carrying information from inner regions engines which they emitted (and photons charged rays cannot reach us). For same reasons, such could reveal...
We present an experimentally feasible scheme to implement holonomic quantum computation in the ultrastrong-coupling regime of light-matter interaction. The large anharmonicity and ${\mathbb{Z}}_{2}$ symmetry Rabi model allow us build effective three-level $\mathrm{\ensuremath{\Lambda}}$-structured artificial atom for computation. proposed physical implementation includes two gradiometric flux qubits microwave resonators where single-qubit gates are realized by a two-tone driving on one...
Fast radio bursts (FRBs) are transients lasting only about a few milliseconds. They seem to occur at cosmological distances. We propose that these events can be originated in the collapse of magnetosphere Kerr-Newman black holes (KNBHs). show closed orbits charged particles objects unstable. After examining dependencies on specific charge particle and spin KNBH, we conclude resulting timescale radiation mechanism fit well with extant observations FRBs. Furthermore, argue merger KNBH binary...
We present the first dynamical model of plasma accretion onto traversable wormholes by performing general relativistic magnetohydrodynamical (GRMHD) simulations flow on both sides wormhole. evolve ideal MHD equations a wormhole spacetime described spherically symmetric Simpson-Visser metric. The disk is initialized one side and accretes throat driven magnetorotational instability (MRI). show that inflowing quickly settles in forms hot, rotating cloud. cloud acts as an engine which gas coming...
We provide an in depth study of the theoretical peculiarities that arise effective negative mass lensing, both for case a point lens and source, extended source situations. describe novel observational signatures arising lensed by mass. show produces total or partial eclipse umbra region also usual Shapiro time delay is replaced with equivalent gain. these features theoretically, as well through numerical simulations. microlensing simulations various intensity profiles discuss differences...
Using 8 telescopes in the northern and southern hemispheres, plus archival data from two on-line sky surveys, we performed a systematic optical spectroscopic study of 39 putative counterparts unidentified or poorly studied INTEGRAL sources order to determine at least better assess their nature. This was implemented within framework our campaign reveal nature newly-discovered and/or detected by INTEGRAL. Our results show that 29 these objects are active galactic nuclei (13 which Seyfert 1...
Context. A population of unidentified gamma-ray sources is forming a structure resembling halo around the Galactic center. These are highly variable, and hence they should be associated with compact objects. Microquasars objects undergoing accretion relativistic jets; if such an object has low-mass, evolved, donor star, it might found in halo. If these low-mass microquasars can generate detectable emission, then natural candidates to account for high-energy sources.
Aims. We investigate the effects of magnetic fields on neutrino production in microquasars.
<i>Context. <i/>The environs of massive, early-type stars have been inspected in recent years the search for sites where particles can be accelerated up to relativistic energies. Wind regions massive binaries that collide already established as sources high-energy emission; however, there is a different scenario strong shocks also produced: bow-shaped region matter piled by action stellar wind runaway star interacting with interstellar medium.<i>Aims. <i/>We study bow-shock produced very...
Context. The well known radiogalaxy Cen A has been recently detected as a source of very high energy (VHE) γ-rays by the HESS experiment just before Fermi/LAT it at energies (HE). detection, together with that M 87, established radiogalaxies VHE γ-ray emitters.
Context. Stellar-mass black holes offer what is perhaps the best scenario to test theories of gravity in strong-field regime. In particular, f(R) theories, which have been widely discus a cosmological context, can be constrained through realistic astrophysical models phenomena around holes.
Dense populations of stars surround the nuclear regions galaxies. In active galactic nuclei, these can interact with relativistic jets launched by supermasive black hole. this work, we study interaction early-type in nuclei. A bow-shaped double-shock structure is formed as a consequence jet and stellar wind each star. Particles be accelerated up to energies shocks emit high-energy radiation. We compute, considering different densities core, gamma-ray emission produced non-thermal radiative...
Scalar Tensor Vector Gravity (STVG) is an alternative theory of gravitation that has successfully explained the rotation curves nearby galaxies, dynamics galactic clusters, and cosmological data without dark matter, but hardly been tested in strong gravity regime. In this work, we aim at building radiative models thin accretion disks for both Schwarzschild Kerr black holes STVG theory. particular, study stable circular equatorial orbits around stellar supermassive spacetimes. We also...