6 research outputs found
Acceptability Conditions and Relativistic Barotropic Equations of State
We sketch an algorithm to generate exact anisotropic solutions starting from
a barotropic EoS and setting an ansatz on the metric functions. To illustrate
the method, we use a generalization of the polytropic equation of state
consisting of a combination of a polytrope plus a linear term. Based on this
generalization, we develop two models which are not deprived of physical
meaning as well as fulfilling the stringent criteria of physical acceptability
conditions. We also show that some relativistic anisotropic polytropic models
may have singular tangential sound velocity for polytropic indexes greater than
one. This happens in anisotropic matter configurations when the polytropic
equation of state is implemented together with an ansatz on the metric
functions. The generalized polytropic equation of state is free from this
pathology in the tangential sound velocity.Comment: 25 pages, 7 figure
The physical acceptability conditions and the strategies to obtain anisotropic compact objects
We studied five methods to include anisotropy, or unequal stress
distributions, in general relativistic matter configurations. We used nine
acceptability conditions that the metric and physical variables must meet to
determine if our models were astrophysically viable. Our analysis found the
most effective way to introduce anisotropy while keeping a simple density
profile. We also found a practical "rule of thumb" that relates the density at
the boundary to the density at the centre of relativistic matter distributions.
Additionally, we calculated the configuration radius and encountered that
values observed by NICER for PSR J0740+6620 are consistent with several
acceptable matter configurations, both isotropic and anisotropic.Comment: 20 pages, 3 figures. Typo correctio
Acceptability conditions and relativistic barotropic equations of state
We sketch an algorithm to generate exact anisotropic solutions starting from a barotropic EoS and setting an ansatz on the metric functions. To illustrate the method, we use a generalization of the polytropic equation of state consisting of a combination of a polytrope plus a linear term. Based on this generalization, we develop two models which are not deprived of physical meaning as well as fulfilling the stringent criteria of physical acceptability conditions. We also show that some relativistic anisotropic polytropic models may have singular tangential sound velocity for polytropic indexes greater than one. This happens in anisotropic matter configurations when the polytropic equation of state is implemented together with an ansatz on the metric functions. The generalized polytropic equation of state is free from this pathology in the tangential sound velocity
Acceptability conditions and relativistic anisotropic generalized polytropes
This paper explored the physical acceptability conditions for anisotropic matter configurations in General Relativity. The study considered a generalized polytropic equation of state for a heuristic anisotropy. We integrated the corresponding LaneâEmden equation for several hundred models and found the parameter-space portion ensuring the physical acceptability of the configurations. Polytropes based on the total energy density are more viable than those with baryonic density, and small positive local anisotropies produce acceptable models. We also found that polytropic configurations where tangential pressures are greater than radial ones are also more acceptable. Finally, convective disturbances do not generate cracking instabilities. Several models emerging from our simulations could represent candidates of astrophysical compact objects
The physical acceptability conditions and the strategies to obtain anisotropic compact objects
We studied five methods to include anisotropy, or unequal stress distributions, in general relativistic matter configurations. We used nine acceptability conditions that the metric and physical variables must meet to determine if our models were astrophysically viable. Our analysis found the most effective way to introduce anisotropy while keeping a simple density profile. We also found a practical ârule of thumbâ that relates the density at the boundary to the density at the centre of relativistic matter distributions. Additionally, we calculated the configuration radius and encountered that values observed by NICER for PSR J0740+6620 are consistent with several acceptable matter configurations, both isotropic and anisotropic