Archive

Archive for the ‘4. Astrophysics’ Category

Mar
23

On the theory of relativistic collapse and relativistic explosion.

2. Quasistable states as glowsars and bursts at recollapse.

Zahid Zakir [1]

Abstract

     At the gravitational collapse of a star the local temperatures in internal layers grow more rapidly than on surface, while the last one grows on world time exponentially. For this reason it is probable formation not a frozar, but an optimistic scenario of the collapse when matter of a star rapidly transfers into the radiation-dominated state with stabilization or further expansion (anticollapse). As a result, at stabilization the star can long on world time be in a hot phase (on local temperature). The semi-frozen relativistic objects in such quasistable phase release highly reddened quasirelict radiation and it is proposed to name this new class of objects as glowsars (glow star). Most of matter of glowsar concentrates near its surface in a radiation-dominated state. At defrosting of the glowsar its expansion at a final stage happens exponentially rapidly (the relativistic explosion) and the object is observed as the relativistic supernova or hypernova. Observable examples of the relativistic explosion, or anticollapse, are, perhaps, the Big Bang and some explosions in astrophysics with huge energy release, do not explained by known processes. Some idealized models and numerical simulations testify that at contracting of massive enough objects growing of pressure and temperature in internal layers can balance the gravitational pull and the explosive expansion is possible. The observable consequences of the predictions of GR about properties of the compact objects in glowsar state and the relativistic explosion are discussed.

PACS: 04.20.Dg; 04.70.-s; 97.60.-s, 98.54.-h

Key words: relativistic stars, collapse, frozars, glowsars, black holes, supernova, quasars

Vol. 7, No 1, p. 14 – 20, v1,  23 March 2012

Online: TPAC: 4100-025 v2,  28 September 2012; DOI: 10.9751/TPAC.4100-025


[1] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan

      zahidzakir@theor-phys.org

Mar
23

On the theory of relativistic collapse and relativistic explosion.

1. Collapse without horizon and formation of frozars.

Zahid Zakir [1]

Abstract

        In general relativity (GR) the surface of a spherical object as an extended body is defined on hypersurfaces of simultaneity t=const and the proper time on the object’s surface at any moment is strongly related to the finite world time moment t (astronomical epoch). At any finite t this proper time moment always is less than its value at which the surface would cross the gravitational radius in the Newtonian theory. It is shown that in GR, as the surface closely approaches the gravitational radius, the proper times rapidly freeze (in terms of t) firstly at the center, where the time delay is maximal, then at higher layers, and that the surface freezes after all layers beyond the gravitational radius. The freezing of all processes in entire volume means the practically stopping of the collapse also. Thus, in GR there is a universal factor preventing the collapse – a strong gravitational dilation of the proper times, a fundamental physical phenomenon with which GR mainly differs from the Newtonian theory. For this reason in GR the horizons and singularities, as the Newtonian theory artifacts, do not arise and the black holes are forbidden. The collapse in GR leads to the formation of the frozars (frozen stars) the surface and all layers in entire volume of which are frozen. The worldlines of the particles in the star are timelike and almost parallel to the taxis and between each other. The formation of the frozars is shown for the standard idealized models of the collapse – a thin dust shell, a dust ball, a star of constant density and a star with ultrarelativistic matter. The astrophysical consequences of the theory of collapsed stars as frozars of GR are shortly discussed.

PACS: 04.20.Dg;  04.70.-s;  97.60.-s,  98.54.-h

Key words: relativistic stars, collapse, frozars, black holes, horizon, singularity, time dilation

Vol. 7, No 1, p. 1 – 13, v1,  23 March 2012

Online: TPAC: 4100-024 v2,  28 September 2012; DOI: 10.9751/TPAC.4100-024


Nov
09

Four-index equations for gravitation and the gravitational energy-momentum tensor [1]

      Zahid Zakir [2]

Abstract

    A new treatment of the gravitational energy on the basis of 4-index gravitational equations is reviewed. The gravitational energy for the Schwarzschild field is considered.

PACS: 04.20.Cv, 04.20.Fy, 11.10.-z

Key words: gravitational energy, curvature tensor, vacuum energy

Vol. 5, No 2,  p. 22 – 25, v1,   9 November 2010

Online: TPAC: 3600-019 v2,  28 September 2012; DOI: 10.9751/TPAC.3600-019

[1] The preprint of the paper has been presented in 1999 (revised 2003): Zakir Z. arXiv:gr-qc/9906039

[2] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan

      zahidzakir@theor-phys.org


Nov
09

Four-index energy-momentum tensors for gravitation and matter [1]

      Zahid Zakir [2]

Abstract

   The 4-index energy-momentum tensors for gravitation and matter are analyzed on the basis of new equations for the gravitational field with the Riemann tensor. Some properties of such defined gravitational energy are discussed.

PACS: 04.20.Cv, 04.20.Fy, 11.10.-z

Key words: gravitational energy, curvature tensor, vacuum energy

Vol. 5, No 2, p. 18 – 21, v1,   9 November 2010

Online: TPAC: 3600-018 v2,  28 September 2012; DOI: 10.9751/TPAC.3600-018


[1] The preprint of the paper has been presented in 1999 (revised 2003): Zakir Z. arXiv:gr-qc/9905036

[2] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan

      zahidzakir@theor-phys.org


Nov
09

New equations for gravitation with the Riemann tensor and 4-index energy-momentum tensors for gravitation and matter [1]

      Zahid Zakir [2]

Abstract

    A generalized version of the Einstein equations in the 4-index form, containing the Riemann curvature tensor linearly, is derived. It is shown, that the gravitational energy-momentum density outside a source is represented across the Weyl tensor vanishing at the 2-index contraction. The 4-index energy-momentum density tensor for matter also is constructed.

PACS: 04.20.Cv, 04.20.Fy, 11.10.-z

Key words: gravitational energy, curvature tensor, vacuum energy

Vol. 5, No 2, p. 14 – 17, v1,   9 November 2010

Online: TPAC: 3600-017 v2, 28 September 2012; DOI:  10.9751/TPAC.3600-017


[1] The preprint of the paper has been presented in 1999 (revised 2003): Zakir Z. arXiv:gr-qc/9905009

[2] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan

      zahidzakir@theor-phys.org


Nov
02

General relativity constrains proper times and predicts frozen stars instead of black holes

Zahid Zakir [1]

Abstract

     In a static gravitational field an intersection of a worldline by a global hypersurface of simultaneity t=const gives an invariant constraint relating the proper time of this event by t. Since at any finite t such constrained proper time intervals are less than required for crossing a horizon, general relativity predicts the gravitational freezing of proper times in stars with timelike or null geodesics everywhere. The time dilation stabilizes contracting massive stars by freezing, which is maximal but finite at the centre and the surface is frozen near the gravitational radius. The frozen stars (frozars) slowly defrost due to emissions and external interactions, the internal phase transitions can initiate refreezing with bursts and explosions.

PACS: 04.20.Dg;  04.70.-s;  97.60.-s,  98.54.-h

Key words: relativistic stars, black holes, quasars, active galactic nuclei, collapse, horizon, singularities

Vol. 2, No 1,  p. 1 – 8, v1,   2 November 2007

Online: TPAC: 2497-006 v2,  28 September 2012; DOI: 10.9751/TPAC.2497-006


[1] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan

      zahidzakir@theor-phys.org

Oct
20

On the theory of gravitationally-frozen superdense and supermassive objects

Zahid Zakir [1]

Abstract

     The black hole paradigm (BHP) is based on an implicit assumption that the collapse occurs quickly not only on proper times of falling particles, but on world time also, and that information about that is retarded only. According to general relativity (GR) in a static field there is a global simultaneity of events, the proper times are slowed down with respect to world time absolutely and these facts are confirmed experimentally by clocks long-term located at different heights. Therefore, the basic assumption of BHP is incompatible with GR, the collapse occurs not quickly, but it needs in really infinity world time. For a falling particle at any finite world time moment its corresponding proper time moment is insufficient for reaching the gravitational radius of the source. As the result, in GR real horizons and physical singularities do not exist, the black holes never be formed. Instead of the black holes GR predicts the gravitationally-frozen states of matter in superdense and supermassive objects. Particles inside of any compact object are frozen by the strong gravitational field so that the time dilation is finite, but maximal at the center and minimal on the surface. In cosmology this fact solves the problem of an initial singularity, in astrophysics allows one to construct a theory of superdense stars, quasars and AGN, in particle physics leads to the ultraviolet finiteness of quantum fields, including quantum gravity.

  PACS:  95.30.Sf, 97.60.Lf, 98.35.Jk, 98.54.-h, 98.80.-k, 04.60.-m

  Key words: black holes, horizon, collapse, singularities, quark stars, quasars, active galactic nuclei, cosmology, quantum gravity

Vol. 1, No 3,  p. 42 – 60, v1,       20 October 2006

Online: TPAC: 2119-004 v2,  28 September 2012; DOI: 10.9751/TPAC.2119-004


[1] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan

      zahidzakir@theor-phys.org