Dark energy and supermassive black holes

Abstract

This paper deals with a cosmological model in which the universe is filled with tachyon dark energy in order to describe current and future accelerating expansion. We obtain that the simplest condition for the regime of phantom energy to occur in this scenario is that the scalar field be Wick rotated to imaginary values which correspond to an axionic field classically. By introducing analytical expressions for the scale factor or the Hubble parameter that satisfy all constraint equations of the used models we show that such models describe universes which may develop a big rip singularity in the finite future. It is argued that, contrary to a recent claim, the entropy for a universe filled with dark energy is definite positive even on the phantom regime where the universe would instead acquire a negative temperature. It is also seen that, whichever the fate of the tachyonic accelerating universe, it will be stable to any fluctuations of the scalar field, and that since the considered models have all an imaginary sound speed, any overdense regions will undergo an accelerate collapse leading rapidly to formation of giant black holes. Finally the conjecture is advanced that these black holes may be the supermassive black holes that most galaxies harbor at their center.

13 pages, RevTex, accepted for publication in Phys. Rev. D

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• Born-Infeld Phantom Gravastars
• Inflation and dark energy arising from geometrical tachyons
• Generalized second law of thermodynamics for a phantom energy accreting BTZ black hole
• Interacting cosmic fluids in power-law Friedmann-Robertson-Walker cosmological models
• Inflation from D3-brane motion in the background of D5-branes
• Topological Approach to Microcanonical Thermodynamics and Phase Transition of Interacting Classical Spins
• A Quintessentially Geometric Model
• Classical and Quantum Reissner-Nordström Black Hole Thermodynamics and first order Phase Transition
• Tachyon field inspired dark energy and supernovae constraints
• Accretion of Holographic Dark Energy : Dependency only upon Horizon Radius of Expanding Universe
• Inflation driven by single geometric tachyon with D-brane orbiting around NS5-branes