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Astron. Astrophys. 335, 894-898 (1998)

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Research Note

The effective velocity and radius of spiral galaxies

L. Vertchenko 1, 2 and R.J. Quiroga 2

1 Departamento de Física e Química, PUC-MG, Caixa Postal 1686, 30.535-610 Belo Horizonte MG, Brazil
2 Departamento de Física, UFMG, Caixa Postal 702, 30.161-970 Belo Horizonte MG, Brazil

Received 29 November 1997 / Accepted 14 April 1998


The averaged radius and velocity respectively associated to global potential and kinetic energies, are computed for spiral galaxies. Such dynamical parameters (effective radius and velocity) can be directly related to observational ones, being [FORMULA] and [FORMULA], where [FORMULA] is either the [FORMULA] radius or the last observed point of the rotation curve of the galaxy and [FORMULA] is its rotational velocity at this radius. It is proposed that the angular momentum can be replaced by the action , [FORMULA], in the study of dynamical characterization of spiral galaxies (see, for instance, the analysis of Campos-Aguilar et al. (1993)).

Key words: galaxies: spiral – galaxies: fundamental parameters

Send offprint requests to: L. Vertchenko at address 1

© European Southern Observatory (ESO) 1998

Online publication: June 26, 1998