We develop analytic solutions for the linear evolution of metric perturbations in the DGP braneworld modified gravity scenario including near-horizon and superhorizon modes where solutions in the bulk are required. These solutions apply to both the self-accelerating and normal branch and elucidate the nature of coordinate singularities and initial data in the bulk as well as their effect on per...

In recent years, a class of compact objects called gravastars have drawn immense interest as regular solutions to end state stellar collapse. Since the energy density involved in collapse process is expected be high, it natural choice study such context modified gravity theories which reduce General Relativity (GR) low regime. We already framed model gravastar framework involving extra dimensio...

We study the shadow produced by a class of rotating black holes surrounded plasma. The metric for these arises applying Newman-Janis algorithm to family spherically symmetric spacetimes, which includes several well known geometries as special cases. derive general expression shape in case that plasma frequency leads separable Hamilton-Jacobi equation light. present two examples we obtain contou...

One of the plausible unification schemes in physics considers the observable universe to be a 4dimensional surface (the “brane”) embedded in a higher-dimensional curved spacetime (the “bulk”). In such braneworld gravity models with infinitely large extra dimensions, black holes evaporate through the emission of the additional gravitational degrees of freedom, resulting in lifetimes of stellar-m...

With the advent of the LHC and the continuing influx of cosmological data, phenomenological aspects of string theory have received renewed attention in recent years and many problems have been properly incorporated in this framework. For instance, recent theoretical considerations in string theory have applied a statistical approach to the enormous landscape of metastable vacua. The large numbe...

We consider fluid perturbations close to the “phantom divide” characterised by p = −ρ and discuss the conditions under which divergencies in the perturbations can be avoided. We find that the behaviour of the perturbations depends crucially on the prescription for the pressure perturbation δp. The pressure perturbation is usually defined using the dark energy rest-frame, but we show that this f...

In the current letter, we study isotropic static spherically symmetric gravastars without charge under framework of braneworld gravity (dimensionally reduced RS-II with positive brane tension) using metric potential Kuchowicz type (which is physically acceptable, non-singular and stable) in Mazur-Motolla conjuncture. We derived free parameters from junction conditions assuming Schwarzschild vac...

We obtain new results for consistent braneworld Kaluza-Klein reductions, showing how we can derive four-dimensional N = 2 gauged supergravity " localised on the AdS 4 brane " as an exact embedding in five-dimensional N = 4 gauged supergravity. Similarly, we obtain five-dimensional N = 2 gauged supergravity localised on an AdS 5 brane as a consistent Kaluza-Klein reduction from six-dimensional N...

The relationship between the metric and nonrelativistic matter distribution depends on the theory of gravity and additional fields, hence providing a possible way of distinguishing competing theories. With the assumption that the geometry and kinematics of the homogeneous universe have been measured, we present a procedure for understanding and testing the relationship between the cosmological ...