1,721,298 research outputs found
Extracting energy from black holes: Short-GRBs, Long-GRBs and GRB afterglows
No full textTokyo, Japan, Universal Academy Press, to appear in "Frontier in Astroparticle Physics and Cosmology
The electrodynamics of the core and the crust components in neutron stars
No full textWe study the possibility of having a strong electric field (E) in Neutron Stars. We consider a system composed by a core of degenerate relativistic electrons, protons and neutrons, surrounded by an oppositely charged leptonic component and show that at the core surface it is possible to have values of E of the order of the critical value for electron-positron pair creation, depending on the mass density of the system. We also describe Neutron Stars in general relativity, considering a system. composed by the core and an additional component: a crust of white dwarf- like material. We study the characteristics of the crust, in particular we calculate its mass Mcrust. We propose that, when the mass density of the star increases, the core undergoes the process of gravitational collapse to a black hole, leaving the crust as a remnant; we compare Mcrust with the mass of the baryonic remnant considered in the fireshell model of GRBs and find that their values are compatible. © 2008 American Institute of Physics
Relativistic collisionless clusters with arbitrarily large central redshift
No full textSome previous results obtained by Rasio, Shapiro, & Teukolsky are analyzed within the theoretical framework developed by Bisnovatyi-Kogan et al. The Rasio et al. configurations are shown to belong to a special family of configurations of equilibrium for relativistic clusters with a constant value of the central cutoff energy W0 ~ 114. A new classification of the configurations of equilibrium into three different regimes in the central redshift versus temperature diagram is proposed. The possible confrontation of these results with observational parameters is outlined briefly
Some remarks on the Zel'dovich-Podurets relativistic solutions for a system of selfgravitating classical particles
No full textWe compare and contrast recent results we have published on a finite system of isothermal self-gravitating particles with the one obtained by Zel'dovich and Podurets
On a new family of stable relativistic star clusters
No full textThe properties of equilibrium of a novel family of collisionless relativistic star clusters shown to be stable in a recent paper are investigated. Each equilibrium configuration is composed of a central relativistic core and an almost Newtonian halo. The central gravitational redshift of these configurations can become infinite
Systems of selfgravitating classical particles with a cutoff in their distribution function
No full textWe examine the relativistic and Newtonian configurations of a system of classical particles with a distribution function with a cutoff in the momentum space. These distributions are obtained as classical limit of more general quantum statistics. The characteristic physical quantities of astrophysical interest of the equilibrium configurations are given, assuming selected values of the parameters. The stability of these configurations is treated both from a global point of view of the mass-central density and mass-radius relation as well as by introducing the concept of an effective polytropic exponent. The results are compared and contrasted with the existing ones in literature
Effective Dyadosphere
No full textIn astrophysical conditions, we discuss (i) an overcritical electric field, (ii) electron-positron-photon plasma, and (iii) the effective Dyadosphere formed in gravitational collapsing process. © 2008 American Institute of Physics
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