Luciano Rezzolla | Goethe-Universität Frankfurt am Main (original) (raw)

Papers by Luciano Rezzolla

Physical Review Letters, 2014

Physical Review D, 2014

ABSTRACT We extend the Wald solution to a black hole that is also boosted. More specifically, we ... more ABSTRACT We extend the Wald solution to a black hole that is also boosted. More specifically, we derive analytic solutions for the Maxwell equations for a rotating black hole moving at constant speed in an asymptotically uniform magnetic test field. By adopting Kerr-Schild coordinates we avoid singular behaviours at the horizon and obtain a complete description of the charge and current distributions in terms of the black-hole spin and boost. Using this solution, we compute the energy losses expected when charged particles are accelerated along the magnetic field lines, improving previous estimates that had to cope with singular electromagnetic fields on the horizon. When used to approximate the emission from binary black holes in a uniform magnetic field, our estimates match reasonably well those from numerical-relativity calculations in the force-free approximation.

Physical Review D, 2013

ABSTRACT We describe in detail the implementation of a simplified approach to radiative transfer ... more ABSTRACT We describe in detail the implementation of a simplified approach to radiative transfer in general relativity by means of the well-known neutrino leakage scheme (NLS). In particular, we carry out an extensive investigation of the properties and limitations of the NLS for isolated relativistic stars to a level of detail that has not been discussed before in a general-relativistic context. Although the numerous tests considered here are rather idealized, they provide a well-controlled environment in which to understand the relationship between the matter dynamics and the neutrino emission, which is important in order to model the neutrino signals from more complicated scenarios, such as binary neutron-star mergers. When considering nonrotating hot neutron stars we confirm earlier results of one-dimensional simulations, but also present novel results about the equilibrium properties and on how the cooling affects the stability of these configurations. In our idealized but controlled setup, we can then show that deviations from the thermal and weak-interaction equilibrium affect the stability of these models to radial perturbations, leading models that are stable in the absence of radiative losses, to a gravitational collapse to a black hole when neutrinos are instead radiated.

General Relativity, Cosmology and Astrophysics, 2014

The Astrophysical Journal, 2012

The Thirteenth Marcel Grossmann Meeting, 2014

The Astrophysical journal, Jan 10, 2000

We show that r-mode oscillations distort the magnetic fields of neutron stars and that their occu... more We show that r-mode oscillations distort the magnetic fields of neutron stars and that their occurrence is likely to be limited by this interaction. If the field is greater, similar1016(Omega/OmegaB) G, where Omega and OmegaB are the angular velocities of the star and at which mass shedding occurs, r-mode oscillations cannot occur. Much weaker fields will prevent gravitational radiation from exciting r-mode oscillations or will damp them on a relatively short timescale by extracting energy from the modes faster than gravitational-wave emission can pump energy into them. For example, a 1010 G poloidal magnetic field that threads the star's superconducting core is likely to prevent the l=2 mode from being excited unless Omega exceeds 0.35OmegaB. If Omega is larger than 0.35OmegaB initially, the l=2 mode may be excited but is likely to decay rapidly once Omega falls below 0.35OmegaB, which happens in less, similar15 days if the saturation amplitude is greater, similar0.1. The r-mod...

Astronomische Nachrichten, 2014

ABSTRACT Magnetic fields represent a crucial aspect of the physics and astrophysics of neutron st... more ABSTRACT Magnetic fields represent a crucial aspect of the physics and astrophysics of neutron stars. Despite its great relevance, the internal magnetic field configuration of neutron stars is very poorly constrained by the observations, and understanding its properties is a long-standing theoretical challenge. The investigation on the subject is focused on the search for those magnetic field geometries which are stable on several Alfv\`en timescales, thus constituting a viable description of neutron star interiors. Assesing the stability of a given magnetic field geometry is therefore an important part of this research. So far only simple configurations, such as the purely poloidal or purely toroidal ones, have been studied in detail in perturbation theory and, most recently, by means of nonlinear magnetohydrodynamic simulations. Here we review the basic results of the state-of-the-art general relativistic nonlinear studies, discussing the present status of the field and its future directions.