Astrophysical and electromagnetic emissivity properties of black holes surrounded by a quintessence type exotic fluid in the Scalar-Vector-Tensor Modified Gravity

The astrophysical consequences of the presence of a quintessence scalar field on the evolution of the horizon and on the accretion disk surrounding a static black hole, in the Scalar-Vector-Tensor version of Modified Gravity (MOG), are investigated. The positions of the stable circular orbits of the massive test particles, moving around the central object, are obtained from the extremum of the effective potential. Detailed calculations are also presented to investigate the light deflection, shadow and Shapiro effect for such a black hole. The electromagnetic properties of the accretion disks that form around such black holes are considered in detail. The energy flux and efficiency parameter are estimated analytically and numerically. A comparison with the disk properties in Schwarzschild geometry is also performed. The quantum properties of the black hole are also considered, and the Hawking temperature and the mass loss rate due to the Hawking radiation are considered. The obtained results may lead to the possibility of direct astrophysical tests of black hole type objects in modified gravity theories.Comment: 30 pages, including diagrams and table

Collision of particles and energy extraction in hyperscaling violation background

In this paper, we investigate particle collision near the charged black hole with hyperscaling violating factor under different conditions on mass, charge and θ parameters. In that case, we calculate the center of mass (CM) energy of two colliding particles on the black hole horizon. We find that unlike the other stationary black holes that have been studied so far, the center of mass energy on the horizon can be infinite in certain conditions. By computing the effective potential, we found that particles can collide with very high CM energy on the horizon at two states. The first is an uncharged black hole with small mass and small θ. The second is a massive black hole with the small value of charge and θ. In addition, we investigate the geodesic motion of particles and plot some possible orbits around this black hole. Then, we obtain the ergosphere extent of the hyperscaling violation charged black hole and found that increasing value of θ, the ergoregion limit reduces and we can not extract energy with large value of θ. We also found that energy extraction from the black hole only depends on the absorbed charge by the black hole

Cyclic and heteroclinic flows near general static spherically symmetric black holes: semi-cyclic flows - addendum and corrigendum

We present new accretion solutions of a polytropic perfect fluid onto an f(R)-gravity de Sitter-like black hole. We consider two f(R)-gravity models and obtain finite-period cyclic flows oscillating between the event and cosmological horizons as well as semi-cyclic critical flows executing a two-way motion from and back to the same horizon. Besides the generalizations and new solutions presented in this work, a corrigendum to Eur. Phys. J. C (2016) 76:280 is provided

Quantum thermodynamics of an M2-M5 brane system

We will investigate a system of M2-M5 branes as a black M2-M5 bound state. The behavior of this system will be investigated at short distances. At such scales, we will have to incorporate quantum gravitational corrections to the supergravity solutions. We will study the non-equilibrium quantum thermodynamics of this black M2-M5 bound state. The quantum work for this solution will be obtained using the Jarzynski equality. We will also study the corrections to the thermodynamic stability of this system from quantum gravitational corrections. We will use the concept of a novel quantum mass to analyze the quantum gravitational corrections to the information geometry of this system. This will be done using effective quantum metrics for this system.Non UBCArts and Social Sciences, Irving K. Barber Faculty of (Okanagan)ReviewedFacultyResearche