Advances in Astrophysics

3

Authors: Paul Halpern, Nick Tomasello

Because of the expansion of space and the finite age of the cosmos, there exists a horizon beyond which the light emitted by objects will never be able to reach us, marking the bounds of the observable universe. One can calculate the current distance to the horizon by tracing the amount of time it would have taken a photon starting from an object currently there to have reached us. In a 2005 paper, Gott et al. derived this distance using first year CMB data from the WMAP survey. However, more recent CMB data collected by the Planck satellite and published in 2013 have since yielded different values of cosmological parameters. In this paper, we have applied these updated parameters to refine the distance to the edge of the observable universe. We have determined a revised value for the radius of the observable universe that is 0.7% smaller than the previous estimate.

14

Authors: Ya. N. Istomin

From the analysis of the flux of high energy particles, E > 3·1018eV , it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, q¯(E) ∝ E −2.7 , with the same index of 2.7 that has the distribution of Galactic cosmic rays before so called knee, E < 3 · 1015eV . However, for the average power of extragalactic sources, which is of E ' 1043erg s−1 , at least two orders exceeds the power emitted by the Galaxy in cosmic rays, assuming that the density of galaxies is estimated as Ng ' 1M pc−3 . Considering that such power can be provided by relativistic jets from active galactic nuclei with the power E ' 1045 − 1046erg s−1 , we estimate the density of extragalactic sources of cosmic rays as Ng ' 10−2 − 10−3 M pc−3 . Assuming the same nature of Galactic and extragalactic rays, we conclude that the Galactic rays were produced by a relativistic jet emitted from the Galactic center during the period of its activity in the past. The remnants of a bipolar jet are now observed in the form of bubbles of relativistic gas above and below the Galactic plane. The break, observed in the spectrum of Galactic rays (knee), is explained by fast escape of energetic particles, E > 3 · 1015eV , from the Galaxy because of the dependence of the coefficient of diffusion of cosmic rays on energy, D ∝ E 0.7 . The obtained index of the density distribution of particles over energy, N(E) ∝ E −2.7−0.7/2 = E −3.05, for E > 3 · 1015eV agrees well with the observed one, N(E) ∝ E −3.1 . Estimated time of termination of the jet in the Galaxy is 4.2 · 104 years ago.

14

Authors: V.U.M.Rao, G. Suryanarayana, Y.Aditya

A new class of a spatially homogeneous and anisotropic Bianchi type V cosmological models of the universe for viscous fluid distribution within the framework of general relativity is investigated by applying suitable functional form for the Hubble parameter H which yields models of the universe that describe an early deceleration and late time acceleration. We have found that cosmological term Λ being very large at initial times relaxes to a genuine cosmological constant at late times. The physical and kinematical parameters of the models are discussed. The models are found to be compatible with the results of recent observations.

23

Authors: Gagik Ter-Kazarian

In previous paper [1], we employ the microscopic theory of black hole to study the observed unusual high luminosity of NuSTAR X-ray pulsations from M82X-2 without the need for significant breaking of Eddington limit. Exploring a spontaneous breaking of gravitation gauge symmetry at huge energies, this theory has smeared out a central singularity of black hole replacing it by the equilibrium, so-called, superdense proto-matter core (SPC), subject to certain rules. In this framework, we think of a M82X-2 as being a spinning intermediate mass black hole. However, for rigorous theoretical solutions, in present report we analytically treat the microscopic model of stationary and axisymmetric rotating black hole. A ring singularity of the Kerr black hole cannot occur, which is now replaced by equilibrium SPC. We calculate the corrections to previous model, introduced by the rotation, of the characteristic phase profile of M82X-2.