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Astron. Astrophys. 330, 474-479 (1998)

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Rotation curves for spiral galaxies and non-Newtonian gravity:
a phenomenological approach

C. Rodrigo-Blanco and J. Pérez-Mercader

Laboratorio de Astrofsica Espacial y Fsica Fundamental (LAEFF), P.O. Box 50727, E-28080 Madrid, Spain

Received 26 March 1996 / Accepted 8 November 1996


Rotation curves of spiral galaxies are known with reasonable precision for a large number of galaxies with similar morphologies. The data implies that non-Keplerian fall-off is seen. This implies that (i) large amounts of dark matter must exist at galactic scales or (ii) that Newtonian gravity must somehow be corrected. We present a method for inverting the integral relation between an elemental law of gravity (such as Newton's) and the gravitational field generated by a thin disk distribution with exponential density. This allows us to identify, directly from observations, extensions of Newtonian gravity with the property of fitting a large class of rotation curves. The modification is inferred from the observed rotation curve and is finally written in terms of Newton's constant or the effective potential of a test mass moving in the field generated by a point-like particle.

Key words: gravitation – galaxies: kinematics and dynamics – methods: analytical – cosmology: dark matter

Send offprint requests to: crb@laeff.esa.es

© European Southern Observatory (ESO) 1998

Online publication: January 16, 1998