A5047009759- Cosmology and Gravitation Theories
- Black Holes and Theoretical Physics
- Pulsars and Gravitational Waves Research
- Noncommutative and Quantum Gravity Theories
- Advanced Differential Geometry Research
- Relativity and Gravitational Theory
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- Nonlinear Waves and Solitons
- Solar and Space Plasma Dynamics
- High-pressure geophysics and materials
- Astrophysics and Cosmic Phenomena
- Advanced Mathematical Physics Problems
- Mechanics and Biomechanics Studies
- Dark Matter and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Nonlinear Photonic Systems
- Advanced Thermodynamics and Statistical Mechanics
- Geophysics and Sensor Technology
- Quantum and Classical Electrodynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Mechanics and Applications
- Particle physics theoretical and experimental studies
- Quantum Electrodynamics and Casimir Effect
Universidad Complutense de Madrid
2019-2025
Institute of Astrophysics and Space Sciences
2016-2022
University of Lisbon
2015-2022
Istituto Nazionale di Fisica Nucleare
2022
University of L'Aquila
2022
Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso
2022
Fudan University
2015-2016
Universidade Federal da Paraíba
2013-2015
Universidad de Oviedo
2007-2015
Délégation Paris 7
2010-2013
We present a novel theory of gravity by considering an extension symmetric teleparallel gravity. This is done introducing, in the framework metric-affine formalism, new class theories where nonmetricity $Q$ nonminimally coupled to matter Lagrangian. More specifically, we consider Lagrangian form $L\ensuremath{\sim}{f}_{1}(Q)+{f}_{2}(Q){L}_{M}$, ${f}_{1}$ and ${f}_{2}$ are generic functions $Q$, ${L}_{M}$ nonminimal coupling entails nonconservation energy-momentum tensor, consequently...
General Relativity and the $\Lambda$CDM framework are currently standard lore constitute concordance paradigm. Nevertheless, long-standing open theoretical issues, as well possible new observational ones arising from explosive development of cosmology last two decades, offer motivation lead a large amount research to be devoted in constructing various extensions modifications. All extended theories scenarios first examined under light consistency, then applied geometrical backgrounds, such...
We study the light rings and shadows of an uniparametric family spherically symmetric geometries interpolating between Schwarzschild solution, a regular black hole, traversable wormhole, dubbed as bounces, all them sharing same critical impact parameter. consider ray-tracing method in order to parameter regions corresponding direct, lensed, photon ring emission, finding broadening these for bounce solutions compared one. Using this, we determine optical appearance bounces when illuminated by...
In this work, we obtain the shadow images of spherically symmetric scalar boson and Proca stars using analytical fittings numerical solutions, when illuminated by a geometrically thin accretion disk. We chose sample four with radii ranging from more compact configurations $R\ensuremath{\sim}9M$ to dilute $R\ensuremath{\sim}20M$, where $M$ is total mass bosonic star. these configurations, absence light sphere (the locus unstable bound geodesics) makes optical appearance be dominated single...
In this work we consider the observational properties of compact boson stars with self-interactions orbited by isotropically emitting (hot-spot) sources and optically thin accretion disks. We two families supported quartic sixth-order self-interaction potentials, choose three samples each them in growing compactness; only those large enough compactness are capable to hold light rings, namely, null bound orbits. For hot spots, using inclination angles...
Abstract The optical appearance of a body compact enough to feature an unstable bound orbit, when surrounded by accretion disk, is expected be dominated luminous ring radiation enclosing central brightness depression typically known as the shadow. Despite observational limitations, rough details this picture have been now confirmed results Event Horizon Telescope (EHT) Collaboration on imaging M87 and Milky Way supermassive objects. However, precise characterization both features—ring...
Abstract The unification of quantum mechanics and general relativity has long been elusive. Only recently have empirical predictions various possible theories gravity put to test, where a clear signal properties is still missing. dawn multi-messenger high-energy astrophysics tremendously beneficial, as it allows us study particles with much higher energies travelling longer distances than in terrestrial experiments, but more progress needed on several fronts. A thorough appraisal current...
We show that electrically charged solutions within the Eddington-inspired Born-Infeld theory of gravity replace central singularity by a wormhole supported electric field. As result, total energy associated with field is finite and similar to found in electromagnetic theory. When certain charge-to-mass ratio satisfied, lowest part mass charge spectrum event horizon disappears, yielding stable remnants. argue quantum effects matter sector can lower these remnants from Planck scale down TeV scale.
We reconsider the problem of $f(R)$ theories gravity coupled to Born-Infeld theory electrodynamics formulated in a Palatini approach, where metric and connection are independent fields. By studying electrovacuum configurations static spherically symmetric space-time, we find solutions which reduce their Reissner-Nordstr\"om counterparts at large distances but undergo important non-perturbative modifications close center. Our new analysis reveals that point-like singularity is replaced by...
The electrically charged Born-Infeld black holes in the Palatini formalism for $f(R)$ theories are analyzed. Specifically we study those supported by a theory $f(R)=R\ifmmode\pm\else\textpm\fi{}{R}^{2}/{R}_{P}$, where ${R}_{P}$ is Planck's curvature. These only differ from their General Relativity counterparts very close to center but may give rise different geometrical structures terms of inner horizons. nature and strength central singularities also significantly affected. In particular,...
We study the structure of a family static, spherically symmetric space-times generated by an anisotropic fluid and governed particular type f(R) theory. find that for range parameters with physical interest, such solutions represent black holes central singularity replaced finite size wormhole. show time-like geodesics null nonzero angular momentum never reach wormhole throat due to infinite potential barrier. For radial geodesics, it takes affine time This means resulting space-time is...
We show that the space of solutions a wide class Ricci-based metric-affine theories gravity can be put into correspondence with general relativity (GR). This allows us to use well-established methods and results from GR explore new gravitational physics beyond it.
The silhouette of a black hole having critical curve (an unstable bound photon orbit) when illuminated by an optically thin accretion disk whose emission is confined to the equatorial plane shows distinctive central brightness depression (the shadow) outer edge consists series strongly lensed, self-similar rings superimposed with disk's direct emission. While size and shape depend only on background geometry, pattern bright dark regions (including depth shadow itself) in image influenced...
We discuss the importance of multi-ring images in optical appearance a horizonless spherically symmetric compact object, when illuminated by an optically thin accretion disk. Such object corresponds to sub-case analytically tractable extension Kerr solution dubbed as {\it eye storm} Simpson and Visser [JCAP \textbf{03} (2022) 011], which merits removing curvature singularities via asymptotically Minkowski core, while harbouring both critical curve infinite potential barrier at center for...
Black holes in General Relativity are described by space-time metrics that simpler comparison to non-vacuum compact objects. However, given the universality of gravitational pull, it is expected dark matter accumulates around astrophysical black holes, which can have an impact overall field, especially at galactic centers, and induce non-negligible effects their observational imprints. In this work we study optical appearance a spherically symmetric hole both when orbited isotropically...
We study static, spherically symmetric solutions with an electric field in extension of general relativity containing a Ricci-squared term and formulated the Palatini formalism. find that all present central core whose area is proportional to Planck times number charges. Far from core, curvature invariants quickly tend those usual Reissner-Nordstr\"om solution, though structure horizons may be different. In fact, besides structures found solution relativity, we black hole just one...
The geometry of a spacetime containing wormhole generated by spherically symmetric electric field is investigated in detail. These solutions arise high-energy extensions General Relativity formulated within the Palatini approach and coupled to Maxwell electrodynamics. Even though curvature divergences generically at throat, we find that these spacetimes are geodesically complete. This provides an explicit example where do not imply singularities.
We investigate the dynamics of a family functional extensions (Eddington-inspired) Born-Infeld gravity theory, constructed with inverse metric and Ricci tensor. provide generic formal solution for connection an Einstein-like representation field equations this theories. For particular cases we consider applications to early-time cosmology find that nonsingular universes cosmic bounce are very robust solutions.
Exploring the characterization of singular black hole spacetimes, we study relation between energy density, curvature invariants, and geodesic completeness using a quadratic $f(R)$ gravity theory coupled to an anisotropic fluid. Working in metric-affine approach, our models solutions represent minimal extensions general relativity (GR) sense that they rapidly recover usual Reissner-Nordstr\"om solution from near inner horizon outwards. The fluid helps modify only innermost geometry....
We study f(R,T) theories of gravity, where T is the trace energy-momentum tensor T_{\mu\nu}, with independent metric and affine connection (metric-affine theories). find that resulting field equations share a close resemblance their metric-affine f(R) relatives once an effective introduced. As result, are second-order no new propagating degrees freedom arise as compared to GR, which contrasts formulation these theories, dynamical scalar degree present. Analogously its counterpart, impose...
We describe a novel procedure to map the field equations of nonlinear Ricci-based metric-affine theories gravity, coupled scalar matter described by given Lagrangian, into General Relativity different Lagrangian. Our analysis considers examples with single and $N$ real fields, either canonical Lagrangians or generalized functions kinetic potential terms. In particular, we consider several explicit involving $f(R)$ Eddington-inspired Born-Infeld gravity model, Lagrangians. show how...
The imaging by the Event Horizon Telescope (EHT) of supermassive central objects at heart M87 and Milky Way (Sgr ${\mathrm{A}}^{\ensuremath{\star}}$) galaxies, has marked first step into peering photon rings brightness depression that characterize optical appearance black holes surrounded an accretion disk. Recently, Vagnozzi et al. [arXiv:2205.07787] used claim EHT size shadow Sgr ${\mathrm{A}}^{\ensuremath{\star}}$ can be inferred calibrated measurements bright ring enclosing it, to...
In this paper, we investigate the gravitational lensing effect for Schwarzschild-like black hole space-time in background of a Kalb-Ramond (KR) field proposed by Yang et al. [Phys. Rev. D 108, 124004 (2023)]. The solution is characterized single extra parameter $l$, which associated to Lorentz symmetry breaking induced KR field. First, calculate exact deflection angle massive and massless particles finite distances using elliptic integrals. Then study weak strong regimes, discussing...