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ANGSIZ: A general and practical method for calculating cosmo

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ANGSIZ: A general and practical method for calculating cosmological distances

Postby owlice » Tue Jul 27, 2010 1:55 pm

ANGSIZ: A general and practical method for calculating cosmological distances

Abstract: 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 $lambda_{0}$ 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 $eta$. Since most other 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.

Credit: Helbig, Phillip; Kayser, Rainer; Schramm, Thomas

Site: ... eadme.html

Bibcode: 1999ascl.soft09002H

Preferred citation method: and an acknowledgement mentioning URL ... eadme.html

ID: ascl:9909.002
Last edited by Ada Coda on Sun Jul 09, 2017 7:14 pm, edited 1 time in total.
Reason: Updated code entry.
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Re: ANGSIZ: A method for calculating cosmological distances

Postby kcd » Sat Aug 17, 2013 7:09 am

Entry updated 08/17/2013: removed old location ( ... eadme.html) of code and replaced with URL to new site.

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