136 research outputs found
Cloud of strings in f(R) gravity
We derive the solution for a spherically symmetric string cloud configuration
in a d-dimensional spacetime in the framework of f(R) theories of gravity. We
also analyze some thermodynamic properties of the joint black hole - cloud of
strings solution. For its Hawking temperature, we found that the dependence of
the mass with the horizon is significantly different in both theories. For the
interaction of a black hole with thermal radiation, we found that the shapes of
the curves are similar, but shifted. Our analysis generalizes some known
results in the literature.Comment: Version accepted for CP
Newtonian View of General Relativistic Stars
Although general relativistic cosmological solutions, even in the presence of
pressure, can be mimicked by using neo-Newtonian hydrodynamics, it is not clear
whether there exists the same Newtonian correspondence for spherical static
configurations. General relativity solutions for stars are known as the
Tolman-Oppenheimer-Volkoff (TOV) equations. On the other hand, the Newtonian
description does not take into account the total pressure effects and therefore
can not be used in strong field regimes. We discuss how to incorporate pressure
in the stellar equilibrium equations within the neo-Newtonian framework. We
compare the Newtonian, neo-Newtonian and the full relativistic theory by
solving the equilibrium equations for both three approaches and calculating the
mass-radius diagrams for some simple neutron stars equation of state.Comment: 6 pages, 3 figures. v2 matches accepted version (EPJC
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