Archive

Archive for the ‘5. Cosmology’ Category

Aug
01

Comoving to expansion Newtonian potential of galaxies and clusters instead of dark matter

 Zahid Zakir [1]

Abstract

    Stretching of the Newtonian potential (NP) at early epochs is investigated and it is shown that observed effects, usually ascribed to a dark matter, can by explained by such stretching only. Increasing by time a radius of the gravitationally-bound region (GBR) and conservation of gravitational energy lead to a new scenario in which values of NP in expanding volume are maintained, while in physical volume are stretched. Really, the energy conservation in expanding volume requires for NP values to be comoving to the expanding shells. In addition, the radius of gravitationally-bound region increases by time due to decreasing of expansion velocity and different shells around galaxy cease expansion at different times. Thus, as far a shell placed from galaxy, as longer it was expanded and thickened, while potential difference on its boundaries remained unchanged. This shifts the values of NP around galaxy proportional to the distance r and, as the result, the gravitational acceleration, from NP’s 1/r^2 dependence, turned to 1/r dependence, as for centrifugal acceleration. This fact naturally explains the known empirical facts, such as flatness of rotation curves and velocity-mass relationships for galaxies and velocity dispersion in clusters.

PACS: 95.30.Sf, 95.35.+d, 98.65.Cw, 98.62.Ck
Key words: gravitation, cosmological expasion, rotation curves, galaxy clusters

Vol. 9, No 2, p. 73 –77, v1,          31 July 2014

Online: TPAC: 4960-039 v1,      31 July 2014;   DOI: 10.9751/TPAC.4960-039


[1] Centre for Theoretical Physics and Astrophyics, Tashkent, Uzbekistan  zahidzakir@theor-phys.org

May
06

New effects in cosmology: frequency and intensity stasis for radiation crossed galaxy clusters

 Zahid Zakir [1]

Abstract

     New effects of stasis of radiation due to switching out from expansion flow at crossing largest gravitationally-bound regions (GBR), such as galaxy clusters, are considered and their observational consequences for supernovae and cosmic microwave background (CMB) data are discussed. The stasis of frequency and intensity of radiation at crossing of large number of clusters appreciably decreases observing redshifts z and magnifies apparent luminosities. Only normal redshifts z’ of photons not crossed clusters are directly related with the cosmic scale factor and thus true distances exceed those which follow from z. The effects increase for distant objects because of smaller inter-cluster distances at early epochs. For the relic radiation crossed the clusters the effects lead to the stasis of its temperature and “heating” with respect to a normally expanded flow outside the cluster. As a result, instead of former paradigm about almost sterile propagation of relic radiation from the recombination epoch, there is an opposite picture. Mixing of relic radiation flows, many times isolated from the expansion flow in GBRs along path, leads to their isotropy and loss of earlier perturbations. The observing anisotropy follows from the stasis effects at crossing of multiple layers of clusters at our nearest environment. The stasis effects allow one to do more exact conclusions from data analysis and lead to revising of distances and properties of extragalactic objects.

PACS:  04.20.Cv, 98.80.-k, 98.80.Jk 95.30.Sf, 97.60.Lf, 98.35.Jk, 98.54.-h

Key words: cosmological models, redshift, extra dimension

Vol. 9, No 1, p. 5 – 17, v1,       6 May 2014

Online: TPAC: 4874-035 v1,    6 May 2014;   DOI: 10.9751/TPAC.4874-035


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

      zahidzakir@theor-phys.org

May
06

A model of the closed universe gravitating in 4-space

 Zahid Zakir [1]

Abstract

     Models of the closed Universe as a thin  3-sphere in 4-space, gravitating along 3-sphere’s radius, are reformulated in a new form, in which at a local environment of an observer the non-relativistic dynamics of a ball is reproduced with a correct energy conservation condition. Corresponding evolution equations for dust matter and radiation in the 3-sphere are obtained and their observational consequences are studied. It is shown that the closed models in 4-space also lead to the “Miniverse” model with a highly oscillating curve for the “distance modulus – redshift” relation.

PACS:  04.20.Cv, 98.80.-k, 98.80.Jk 95.30.Sf, 97.60.Lf, 98.35.Jk, 98.54.-h

Key words: cosmological models, redshift, extra dimension

Vol. 9, No 1, p. 1 – 4, v1,   6 May 2014

Online: TPAC: 4874-034 v1,  6 May 2014;   DOI: 10.9751/TPAС.4874-034


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

      zahidzakir@theor-phys.org

Nov
13

Models of the Universe with strongly conserved energy of matter

 Zahid Zakir [1]

Abstract

     It is shown that earlier in the Friedmann models requirements of nonrelativistic dynamics of a dust ball, concerning the energy conservation, have not been obeyed, which then led to inconsistency at formulation of relativistic models too. It is proposed a method for reformulation of models of relativistic cosmology when at small distances they naturally coincide by the nonrelativistic model of the dust ball. As the result, in such modified model some of former problems of the Friedmann models do not arise.

PACS:  04.20.Cv, 98.80.-k, 98.80.Jk 95.30.Sf, 97.60.Lf, 98.35.Jk, 98.54.-h, 98.80.-k, 04.60.-m  

Key words: cosmological models, energy conservation, redshift

Vol. 8, No 3, p. 67 – 74, v1,   13 November 2013

Online: TPAC: 4700-033 v1,  13 November 2013;   DOI: 10.9751/TPAC.4700-033


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

      zahidzakir@theor-phys.org

May
15

The closed model of the universe with relativistic redshift

 Zahid Zakir [1]

Abstract

     Starting from the relativistic dynamics of homogeneous expanding ball, a relativistic evolution equation for the closed model of the Universe is formulated which correctly takes into account a relativistic time dilation of proper times due to different expansion speeds at different epochs. The hypersurface of simultaneity of the Universe is spherically-symmetric only in the rest frame of 3-sphere’s centre and, consequently, the evolution is described in world time t of this frame of reference. This relativistic evolution equation coincided with Einstein’s equation for a 3-sphere expanding in 4-space (without dark energy) and has a simple exact solution. There is a relativistic redshift leading to new relation of redshift with the scale factor which then gives new “luminosity-redshift” relation well describing the data for Type 1а supernovae at admissible parameters. By using the initial data – present radius and expansion speed – other properties and evolution of the Universe are predicted. The model predicts that the observing baryon density is one third of total matter density and remaining two third is dark matter density. The accounting of stasis effects slightly changes the parameters only.

  PACS04.20.Cv, 98.80.-k, 98.80.Jk 95.30.Sf, 97.60.Lf, 98.35.Jk, 98.54.-h, 98.80.-k, 04.60.-m  

  Key words: cosmological models, redshift, supernovae, galaxy clusters, dark matter, dark energy  

Vol. 8, No 2, p. 24 – 36, v1,               15 May 2013

Online: TPAC: 4518-030 v1,             15 May 2013; DOI: 10.9751/TPAC.4518-030


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

      zahidzakir@theor-phys.org

May
15

The model of the closed Universe with relativistic effects of extra dimension

 Zahid Zakir [1]

Abstract

     In the standard general relativity (GR) a closed universe as a 3-sphere exists only at embedding into a real 4-space and a hypersurface of simultaneity of the universe is spherically-symmetric only in a global static frame where the center of the 3-sphere is rested. For this reason the evolution of the universe is described in a world time of this frame, where Einstein’s equations with homogeneous matter (without dark energy) have simple exact solutions. The radial speed of 3-sphere leads to the relativistic delay of proper times, which then leads to new expansion law and relativistic redshift. By using the initial data – present radius and velocity of expansion – other properties and evolution of the Universe are predicted and are in agreement with the data. As the result, from standard GR and observations follow that the Universe is closed, slowing down and the extra dimension probably really exist. The evolution is described for all epochs by taking into account pressure in earlier epochs. The nucleosynthesis and recombination occur at sufficiently smaller concentrations, but during sufficienly longer times. It is shown that the model is free on the cosmological problems of former approaches.

PACS:  04.20.Cv, 98.80.-k, 98.80.Jk 95.30.Sf, 97.60.Lf, 98.35.Jk, 98.54.-h, 98.80.-k, 04.60.-m  

Key words: cosmological models, redshift, supernovae, Big Bang, nucleosynthesis, recombination, cosmic microwave background, cosmological problems  

Vol. 8, No 2, p. 37 – 61, v1,               15 May 2013

Online: TPAC: 4518-031 v1,             15 May 2013; DOI: 10.9751/TPAC.4518-031


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

zahidzakir@theor-phys.org

Apr
15

The frequency and intensity stasis effects for radiation crossed galaxy clusters.

2. Isotropy and anisotropy of CMB

 Zahid Zakir [1]

Abstract

     In the previous two papers it has been studied a new class of general relativistic effects – the frequency and intensity stasis of radiation crossing gravitationally-bound regions (GBRs), such as galaxy clusters, due to switching out from the cosmological expansion flow. In the present paper the theory of stasis effects is applied to cosmic microwave background (CMB). For a part of CMB crossing a cluster these effects lead to the stasis of its temperature and «heating» w.r.t. a normally expanded flow outside the cluster. As a result, instead of former paradigm about almost sterile propagation of CMB from the recombination epoch, in fact, general relativity and cosmological principle lead to the opposite picture. Mixing of flows of relic photons, repitedly isolated many times from expansion flow in GBRs along their path, sufficienly changes the physical characteristics of CMB, particularly, leads to its isotropy and loss of earlier times perturbations. The observing anisotropy follows from the stasis effects at crossing of multiple layers of clusters at our nearest environment.

PACS: 98.80.Es, 97.60.Bw, 98.65.Cw, 98.62.Py, 98.62.Ck, 98.62.Qz, 98.80.Jk, 98.70.Vc

Key words: cosmology, galaxy clusters, gravitation, background radiation, anisotropy  

Vol. 8, No 1, p. 16 –23, v1,  15 April 2013

Online: TPAC: 4488-029 v1,   15 April 2013; DOI: 10.9751/TPAC.4488-029


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

      zahidzakir@theor-phys.org

 

Apr
15

 The frequency and intensity stasis effects for radiation crossed galaxy clusters.

1. Localized sources.

 Zahid Zakir [1]

Abstract

     In the previous paper it has been proposed and preliminary studied a new class of general relativistic effects following from switching out of radiation from the cosmological expansion flow at crossing the largest gravitationally-bound regions, such as galaxy clusters. In the present paper more consistent theory of such stasis effects is formulated and its observational consequences are considered, particularly, in this first part of paper the corrections to observational data for Type 1а supernovae are presented. Preservation of frequency and intensity of radiation at crossing large number of clusters leads to sufficient decreasing of observable redshifts z and higher apparent luminosities of sources. Only normal redshifts z’ of photons not crossed clusters, which give true distances exceeding the distances following from z, are directly related with the scale factor. The effects increase for distant objects because of smaller inter-cluster distances at early epochs. The existence of the stasis effects for radiation leads not only to new and more exact data analysis methods in extragalactic astrophysics and cosmology, but also to the revising of distance scales and properties of objects all classes.

PACS: 98.80.Es, 97.60.Bw, 98.65.Cw, 98.62.Py, 98.62.Ck, 98.62.Qz, 98.80.Jk

Key words: cosmology, gravitation, galaxy clusters, supernovae, redshift 

Vol. 8, No 1, p. 7 –15, v1,  15 April 2013

Online: TPAC: 4488-028 v1,   15 April 2013; DOI: 10.9751/TPAC.4488-028


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

      zahidzakir@theor-phys.org

 

Apr
15

Redshift stasis of photons at crossing the gravitationally-bound regions revises the supernovae data

 Zahid Zakir [1]

Abstract

     In gravitationally-bound regions (GBR), largest of which are galaxy clusters, metrics is averagely static and here objects, including radiation, do not participate at the cosmological expansion. In the paper the discovery of new observable effects for radiation crossed such regions – the redshift stasis and flux amplification – is reported. The stasis of wavelength appears as a blueshift with respect to a normally expanded flux and the stasis of distances between photons appears as a higher luminosity. Due to smaller inter-cluster distances at earlier epochs, the corrections to observing redshifts and magnitudes grow with distance. It is shown that the influence to the crossing radiation of switching off on expansion flow is significant and it may exceed up to two or three orders the ordinary gravitational effects of clusters. This sufficiently revises the estimations of characteristics of extragalactic objects and the confrontation with observations of cosmological models becomes correct only at accounting of these stasis effects. The stasis effects sufficiently change temperature of cosmic microwave background and its anisotropy also and lead to new blueshift effects, which particularly may appear in observations as a “dark flow”.

PACS: 98.80.Es, 97.60.Bw, 98.65.Cw, 98.62.Py, 98.62.Ck, 98.62.Qz, 98.80.Jk, 98.70.Vc

Key words: cosmology, gravitation, galaxy clusters, supernovae, redshift, background radiation

Vol. 8, No 1, p. 1 – 6, v2,  15 April 2013

Online: TPAC: 4488-027 v1,   15 April 2013; DOI: 10.9751/TPAC.4488-027


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

      zahidzakir@theor-phys.org

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