J/A+A/318/680 Cosmological distances (Kayser+ 1997)
A general and practical method for calculating cosmological distances
Kayser R., Helbig P., Schramm T.
<Astron. Astrophys. 318, 680 (1997)>
=1997A&A...318..680K 1997A&A...318..680K (SIMBAD/NED BibCode)
ADC_Keywords: Gravitational lensing
Keywords: cosmology: theory - methods: numerical - cosmology: distance scale -
cosmology: miscellaneous - gravitational lensing
Description:
The calculation of distances is of fundamental importance in
extragalactic astronomy and cosmology. However, no practical
implementation for the general case has previously been available. We
derive a second-order differential equation for the angular size
distance valid not only in all homogeneous Friedmann-Lemaitre
cosmological models, parametrised by λ0 and {OMEGA}0, but
also in inhomogeneous `on-average' Friedmann-Lemaitre models, where
the inhomogeneity is given by the (in the general case
redshift-dependent) parameter η. Since most other cosmological
distances can be obtained trivially from the angular size distance,
and since the differential equation can be efficiently solved
numerically, this offers for the first time a practical method for
calculating distances in a large class of cosmological models. We also
briefly discuss our numerical implementation, which is publicly
available.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
angsiz.tex 80 761 LaTeX version of the Appendix
angsiz.aux 151 158 Auxiliary file required to process angsiz.tex
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Acknowledgements: Phillip Helbig
(End) Patricia Bauer [CDS] 06-May-1996