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In previous work we found that many of the spectral properties of low mass x-ray binaries (LMXB), including galactic black hole candiates (GBHC) were consistent with the existence of intrinsically magnetized central objects. We review and…

Astrophysics · Physics 2007-05-23 Stanley L. Robertson , Darryl J. Leiter

The spectral, timing, and jet formation properties of neutron stars in low mass x-ray binary systems are influenced by the presence of central magnetic moments. Similar features shown by the galactic black hole candidates (GBHC) strongly…

Astrophysics · Physics 2007-05-23 Stanley L. Robertson , Darryl J. Leiter

In previous work we found that many of the spectral properties of low mass x-ray binaries, including galactic black hole candidates could be explained by a magnetic propeller model that requires an intrinsically magnetized central object.…

Astrophysics · Physics 2009-11-10 Stanley L. Robertson , Darryl J. Leiter

In previous work we found that the spectral state switch and other spectral properties of both neutron star (NS) and galactic black hole candidates (GBHC), in low mass x-ray binary systems could be explained by a magnetic propeller effect…

Astrophysics · Physics 2009-11-10 Stanley L. Robertson , Darryl J. Leiter

Magnetic Eternally Collapsing Objects (MECO) have been proposed as the central engines of galactic black hole candidates (GBHC) and supermassive active galactic nuclei (AGN). Previous work has shown that their luminosities and spectral and…

General Physics · Physics 2020-01-31 Stanley L. Robertson

There are many observational evidences for the existence of massive compact condensations in the range $10^6 -10^{10} M_\odot$ at the core of various galaxies. At present such condensations are commonly interpreted as Black Holes (BHs).…

Astrophysics · Physics 2007-05-23 Abhas Mitra

Fundamental fields are a natural outcome in cosmology and particle physics and might therefore serve as a proxy for more complex interactions. The equivalence principle implies that all forms of matter gravitate, and one therefore expects…

General Relativity and Quantum Cosmology · Physics 2014-05-28 Hirotada Okawa , Helvi Witek , Vitor Cardoso

Proof that black holes exist will likely require confirmation of the existence of event horizons. The common assumption that the mere existence of large compact masses proves the case for black holes is an unwarranted extrapolation of…

Astrophysics · Physics 2007-05-23 Stanley L. Robertson

In a recent paper[1], it has been shown that, there cannot be any rotating (Kerr) Black Hole (BH) with finite mass in order that the generic properties associated with the symmetries of stationary axisymmetric Einstein equations are obeyed,…

Astrophysics · Physics 2016-08-30 Abhas Mitra

General relativity admits a plethora of exact compact object solutions. The augmentation of Einstein's action with non-minimal coupling terms leads to modified theories with rich structure, which, in turn, provide non-trivial solutions with…

General Relativity and Quantum Cosmology · Physics 2022-05-31 Nikos Chatzifotis , Christoforos Vlachos , Kyriakos Destounis , Eleftherios Papantonopoulos

Within a semiclassical framework, we investigate spherically symmetric solutions of the Einstein equations that (i) develop a trapped region within a finite time as measured by distant observers, and (ii) remain sufficiently regular at the…

General Relativity and Quantum Cosmology · Physics 2025-09-16 Swayamsiddha Maharana , Rama Vadapalli

Based on the conformal energy theorem we prove the uniqueness theorem for static higher dimensional electrically and magnetically charged black holes being the solution of Einstein (n-2)-gauge forms equations of motion. Black hole spacetime…

High Energy Physics - Theory · Physics 2009-11-10 Marek Rogatko

Available proofs of the regularity of stationary black hole event horizons rely on certain assumptions on the existence of sections that imply a $C^1$ differentiability assumption. By using a quotient bundle approach, we remedy this problem…

General Relativity and Quantum Cosmology · Physics 2025-08-12 R. A. Hounnonkpe , E. Minguzzi

The spectrum of known black-hole solutions to the stationary Einstein equations has been steadily increasing, sometimes in unexpected ways. In particular, it has turned out that not all black-hole-equilibrium configurations are…

General Relativity and Quantum Cosmology · Physics 2015-06-05 Piotr T. Chruściel , João Lopes Costa , Markus Heusler

In this brief report, we investigate the existence of 4-dimensional static spherically symmetric black holes (BHs) in the Einstein-complex-scalar-Gauss-Bonnet (EcsGB) gravity with an arbitrary potential $V(\phi)$ and a coupling $f(\phi)$…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Kai Lin , Shaojun Zhang , Chao Zhang , Xiang Zhao , Bin Wang , Anzhong Wang

We provide a new regular black hole solution (RBH) in Einstein Gauss-Bonnet (EGB) gravity with localized sources of matter in the energy--momentum tensor. We determine the necessary constraints in order for the solution to be regular.…

General Relativity and Quantum Cosmology · Physics 2023-08-03 Milko Estrada , Rodrigo Aros

Based on perturbation theory, we present the exact first-order solution to the Einstein equations for the exterior static gravitational field of an isolated non-rotating star in a spatially finite universe having the topology of a flat…

General Relativity and Quantum Cosmology · Physics 2016-08-11 Frank Steiner

As Einstein's gravity is a non-renormalizable theory, it can be a good description of physics only at the scales of energy or spacetime curvature below the Planck mass. Moreover, it requires the presence of an infinite tower of…

General Relativity and Quantum Cosmology · Physics 2025-08-22 Ziyue Zhu , Alexey S. Koshelev , Yang Liu , Anna Tokareva

Recent work has linked the quiescent luminosities and hard/soft spectral state switches of neutron stars (NSs) to their spinning magnetic fields. It is shown here that the quiescent luminosities and spectral switches of galactic black hole…

Astrophysics · Physics 2007-05-23 Stanley L. Robertson

In spherical symmetry, solutions of the semiclassical Einstein equations belong to one of two possible classes. Both classes contain solutions that -- depending on the dynamic behavior of the horizon -- describe evaporating physical black…

General Relativity and Quantum Cosmology · Physics 2022-03-10 Pravin K. Dahal , Sebastian Murk , Daniel R. Terno
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