Black holes and naked singularities from Anton–Schmidt’s fluids

Abstract

Adopting the Tolman-Oppenheimer-Volkoff formalism, we propose a new analytical solution for a static and spherically symmetric black hole where the cosmological constant is generalized to a nonisotropic Anton-Schmidt fluid acting as a unified dark energy -dark matter source. Our novel result can describe a black hole in energetic equilibrium with the surrounding universe. We thus investigate the interplay between the mass of the black hole and the parameters of the Anton-Schmidt equation of state, and physically interpret the solution as a family of space-time metrics that may describe both Schwarzschild-de Sitter black holes and naked singularities. The result opens a new window for further constraining the physical properties of the cosmic fluid using the Event Horizon Telescope results, which complement the analysis relying on classical cosmological observations.

Epicyclic frequencies in static and spherically symmetric wormhole geometries

“…II), which is very useful to disentangle among gravitational and inertial effects, and it also permits to have a direct connection with the classical description, assigning therefore a precise physical meaning to the quantities theoretically manipulated, see Eqs. ( 6) and (7). There is a direct way to obtain the epicyclic frequencies through the formulas [23,24]:…”

“…These objects have been extensively studied in the literature, indeed there are many authors, who not only built up new WH solutions, both in General Relativity (GR) and in Alternative Gravity, but they were also interested in analysing their properties [2][3][4][5][6][7][8]. On the other hand, there is also a major research effort in conceiving original astrophysical strategies to search for WH observational signatures [9][10][11][12][13][14][15][16][17][18][19].…”

Testing wormhole solutions in extended gravity through the Poynting-Robertson effect

“…On the other hand, since the WH metric parameters strictly depend on the underlying gravity theory (see, e.g. [47][48][49][50][51][52]), this approach could be also considered as a further method to test extended/alternative gravity models.…”

Reconstructing wormhole solutions in curvature based Extended Theories of Gravity

“…Wormholes (WHs) are exotic compact objects characterized by no horizon and singularities, and endowed a e-mail: vittorio.defalco@physics.cz b e-mail: emmanuele.battista@kit.edu c e-mail: capozziello@unina.it d e-mail: mariafelicia.delaurentis@unina.it with a traversable bridge, called WH neck, connecting two universes or two different regions of the same spacetime [1]. They have been extensively investigated in the literature, and the papers on such a topic can be distinguished in two categories: (1) finding/constructing solutions in General Relativity (GR) or in extended/ alternative theories of gravity [2,3,4,5,6,7]; (2) proposing methods to observationally determine their existence considering reliable fluids or astrophysical probes capable of making these objects stable and traversable structures [8,9,10,11,12,13,14,15]. Regarding the last point, the mentioned strategies are all based on analysis in full and strong gravitational field regimes.…”

“…It seems a general feature of several classes of gravitational models, where the particular case is just represented by GR, because such corrections are not present. The parameters of the Yukawa-like corrections can be constrained by different sets of data [28,29,7,30], allowing thus to reconstruct reliable WH models in agreement with the observations.…”