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Full-Text Articles in Physical Sciences and Mathematics
Particle Transport And Stochastic Acceleration In The Giant Lobes Of Centaurus A, Stephen O'Sullivan
Particle Transport And Stochastic Acceleration In The Giant Lobes Of Centaurus A, Stephen O'Sullivan
Conference papers
The conditions within the giant lobes of Centaurus A are reviewed in light of recent radio and γ‐ray observations. Data from WMAP and ground‐based telescopes in conjunction with measurements from Fermi‐LAT constrain the characteristic field strength and the maximum electron energy. The implications for the transport of energetic particles are discussed in terms of residence times and cooling times within the lobes. Acceleration of electrons and UHECR via the second order Fermi mechanism is discussed.
A Model For Predicting Extragalactic Jet Lifetimes, Daniel S. Spicer, Robert Bingham, Stephen O'Sullivan
A Model For Predicting Extragalactic Jet Lifetimes, Daniel S. Spicer, Robert Bingham, Stephen O'Sullivan
Articles
Abstract. In this letter, we propose a model to explain the disintegration of ex- tragalactic jets and to predict the associated timescale. The model assumes that a jet is current and charge neutral as well as collimated at its source; however, the forward electron current gradually decays producing a magnetic field transverse to the direction of jet propagation. This growing transverse magnetic field eventually causes the jet to disintegrate.
Stochastic Particle Acceleration In The Lobes Of Giant Radio Galaxies, Stephen O'Sullivan, Brian Reville, Andrew Taylor
Stochastic Particle Acceleration In The Lobes Of Giant Radio Galaxies, Stephen O'Sullivan, Brian Reville, Andrew Taylor
Articles
We investigate the acceleration of particles by Alfv ́en waves via the second-order Fermi process in the lobes of giant radio galaxies. Such sites are candidates for the accelerators of ultra-high-energy cosmic rays (UHECR). We focus on the nearby Fanaroff–Riley type I radio galaxy Centaurus A. This is motivated by the coincidence of its position with the arrival direction of several of the highest energy Auger events. The conditions necessary for consistency with the acceleration time-scales predicted by quasi-linear theory are reviewed. Test particle calculations are performed in fields which guarantee electric fields with no component parallel to the local …
Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev
Reissner–Nordstrom Expansion, Emil Prodanov, Rossen Ivanov, Vesselin Gueorguiev
Articles
We propose a classical mechanism for the cosmic expansion during the radiation-dominated era, assuming the Universe as a two-component gas. The first component is the ultra-relativistic “standard” fraction described by an equation of state of an ideal quantum gas of massless particles. The second component consist of superheavy charged particles and their interaction with the “standard” fraction drives the expansion. This interaction is described by the Reissner–Nordstr¨om metric purely geometrically — the superheavy charged particles are modeled as zero-dimensional naked singularities which exhibit gravitational repulsion. The radius of a repulsive sphere, surrounding a naked singularity of charge Q, is inversely …
Riemann Tensor Of The Ambient Universe, The Dilaton, And Newton’S Constant, Rossen Ivanov, Emil Prodanov
Riemann Tensor Of The Ambient Universe, The Dilaton, And Newton’S Constant, Rossen Ivanov, Emil Prodanov
Articles
We investigate a four-dimensional world, embedded into a five-dimensional spacetime, and find the five-dimensional Riemann tensor via generalisation of the Gauss (--Codacci) equations. We then derive the generalised equations of the four-dimensional world and also show that the square of the dilaton field is equal to the Newton's constant. We find plausable constant and non-constant solutions for the dilaton. Comment: 5 pages, revtex
Bouncing Branes, Emil Prodanov
Bouncing Branes, Emil Prodanov
Articles
Two classical scalar fields are minimally coupled to gravity in the Kachru-Shulz-Silverstein scenario with a rolling fifth radius. A Tolman wormhole solution is found for a R x S^3 brane with Lorentz metric and for a R x AdS_3 brane with positive definite metric.