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D. C. Tatarski

Publications and source records attributed to D. C. Tatarski.

5 recordsLinked to original sources
arXiv1994

Cosmological Observations in a Local Void

A local void in the globally Friedmann-Robertson-Walker (FRW) cosmological model is studied. The inhomogeneity is described using the Lema\^ıtre-Tolman-Bondi (LTB) solution with the spherically symmetric matter distribution based on the faint galaxies number counts. We investigate the effects this has on the measurement of the Hubble constant and the redshift--luminosity distance relation for moderately and very distant objects ($z \approx 0.1$ and more). The results, while fully compatible with cosmological observations, indicate that if we happened to live in such a void, but insisted on interpreting cosmological observations through the FRW model, we could get a few unexpected results. For example the Hubble constant measurement could give results depending on the separation of the source and the observer.

astro-ph↗
arXiv1994

The Age of the Universe, the Hubble Constant and QSOs in a Locally Inhomogeneous Universe

A local void in the globally Friedmann-Robertson-Walker cosmological model with the critical density ($Ω_{0}=1$) is studied. The inhomogeneity is described using a Lema\^ıtre-Tolman-Bondi solution for a spherically symmetric distribution of matter. The scale of the central underdense region is $\sim 150$ Mpc. We investigate the effects this has on the cosmological time scale, the measurement of the Hubble constant and the redshift--luminosity distance for moderately and very distant objects ($z \sim 0.1$ and more). The results indicate that if we happened to live in such a void, but insisted on interpreting cosmological observations through the FRW model, we could go wrong in a few instances. For example, the Hubble constant measurement could give results depending on the separation of the source and the observer, the quasars could be younger than we think and also less distant (less energetic).

astro-ph↗
arXiv1993

Gravitational Waves from an Axi-symmetric Source in the Nonsymmetric Gravitational Theory

We examine gravitational waves in an isolated axi--symmetric reflexion symmetric NGT system. The structure of the vacuum field equations is analyzed and the exact solutions for the field variables in the metric tensor are found in the form of expansions in powers of a radial coordinate. We find that in the NGT axially symmetric case the mass of the system remains constant only if the system is static (as it necessarily is in the case of spherical symmetry). If the system radiates, then the mass decreases monotonically and the energy flux associated with waves is positive.

gr-qc↗
arXiv1992

Gravitational Waves from an Axi-symmetric Source in the Nonsymmetric Grav. Theory

We examine gravitational waves in an isolated axi--symmetric reflexion symmetric NGT system. The structure of the vacuum field equations is analyzed and the exact solutions for the field variables in the metric tensor are found in the form of expansions in powers of a radial coordinate. We find that in the NGT axially symmetric case the mass of the system remains constant only if the system is static (as it necessarily is in the case of spherical symmetry). If the system radiates, then the mass decreases monotonically and the energy flux associated with waves is positive.

gr-qc↗