相关论文: Spherical neutron star collapse toward a black hol…
We study the interaction of massless scalar fields with self-gravitating neutron stars by means of fully dynamic numerical simulations of the Einstein-Klein-Gordon perfect fluid system. Our investigation is restricted to spherical symmetry…
Tensor-scalar theory of gravity allows the generation of gravitational waves from astrophysical sources, like Supernov\ae{}, even in the spherical case. That motivated us to study the collapse of a degenerate stellar core, within…
The class of scalar-tensor theories with the scalar field coupling to the Gauss-Bonnet invariant has drawn great interest since solutions of spontaneous scalarization were found for black holes in these theories. We contribute to the…
In a certain class of scalar-Gauss-Bonnet gravity, the black holes and the neutron stars can undergo spontaneous scalarization -- a strong gravity phase transition triggered by a tachyonic instability due to the nonminimal coupling between…
Scalar-tensor theories of gravity are extensions of General Relativity (GR) including an extra, nonminimally coupled scalar degree of freedom. A wide class of these theories, albeit indistinguishable from GR in the weak field regime,…
The collapse of spherical neutron stars is studied in General Relativity. The initial state is a stable neutron star to which an inward radial kinetic energy has been added through some velocity profile. For two different equations of state…
We present numerical-relativity simulations of spherically symmetric core collapse and compact-object formation in scalar-tensor theories of gravity. The additional scalar degree of freedom introduces a propagating monopole…
Scalar-tensor theories of gravity are natural phenomenological alternatives to General Relativity, where the gravitational interaction is mediated by a scalar degree of freedom, besides the usual tensor gravitons. In regions of the…
The recent observations of neutron star mergers have changed our perspective on scalar- tensor theories of gravity, favouring models where gravitational waves travel at the speed of light. In this work we consider a scalar-tensor set-up…
We identify a class of scalar-tensor theories with coupling between the scalar and the Gauss-Bonnet invariant that exhibit spontaneous scalarization for both black holes and compact stars. In particular, these theories formally admit all of…
Proto-neutron stars are born when a highly evolved and massive star collapses under gravity. In this paper, we investigate the spontaneous scalarization in proto-neutron stars. Based on the scalar tensor theory of gravity as well as the…
This paper provides an extended exploration of the inverse-chirp gravitational-wave signals from stellar collapse in massive scalar-tensor gravity reported in [Phys. Rev. Lett. {\bf 119}, 201103]. We systematically explore the parameter…
We present a full 3D numerical evolution code to study neutron stars in massive-scalar-tensor theories. The code is embedded in the Einstein Toolkit framework and its implementation constitutes a modified version of the…
Although general relativity passes all precision tests to date, there are several reasons to go beyond the current model of gravitation and search for new fundamental physics. This means looking for new, so far undetected, fields. Scalars…
We analyze numerically the dynamical transition to spontaneous scalarization in neutron stars in the framework of a scalar-tensor theory of gravity where the scalar field is free but massive, and it is coupled nonminimally to gravity in the…
Unlike general relativity, the scalar gravitational waves can be excited due to the radial oscillations in scalar-tensor gravity. To examine the scalar gravitational waves in scalar-tensor gravity, we derive the evolution equations of the…
We investigate the dynamics of self-gravitating, spherically-symmetric distributions of fluid through numerical means. In particular, systems involving neutron star models driven far from equilibrium in the strong-field regime of general…
Unlike general relativity, scalar-tensor theories of gravity predict scalar gravitational waves even from a spherically symmetric gravitational collapse. We solve numerically the generation and propagation of the scalar gravitational wave…
We study how the gravitational wave signal from stellar collapse in scalar-tensor gravity varies under the influence of scalar self-interaction. To this end, we extract the gravitational radiation from numerical simulations of stellar…
Scalar-tensor theories are among the most promising alternatives to general relativity that have been developed to account for some long standing issues in our understanding of gravity. Some of these theories predict the existence of a…