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(gzipped) PostScript## An analysis of 900 optical rotation curves: the universal rotation curve as a power-law and the development of a theory-independent dark-matter modeller
One of the largest rotation curve data bases of spiral galaxies currently available is that provided by Persic & Salucci, hereafter PS 1995, which has been derived by them from unreduced rotation curve data of 965 southern sky spirals obtained by Mathewson, Ford & Buchhorn, hereafter MFB 1992. Of the original sample of 965 galaxies, the observations on 900 were considered by PS 1995 to be good enough for rotation curve studies, and the present analysis concerns itself with these 900 rotation curves. The analysis is performed within the context of the basic
hypothesis that the phenomenology of rotation curves in the optical
disc (that is, away from the dynamical effects of the bulge) can be
systematically described in terms of a general power-law
, valid for
, where
is an estimate of the transition
radius between bulge-dominated and disc-dominated dynamics. The
analysis begins by showing how this model provides an extremely good
description of the generic behaviour of rotation curves in the optical
disc and, furthermore, how it imposes very detailed correlations
between the free parameters, These correlations are investigated, and shown to imply, via first
and second-order models, a third-order model according to which the
rotation velocity, Furthermore, it is shown that the conclusion of PS 1986, that optical-disc dynamics contain no signature of the transition from disc-dominated dynamics to halo-dominated dynamics, is extremely strongly supported by this analysis.
Online publication: March 1, 1999 |