Daily Archives: July 18, 2007

Using GCs to test gravity in the weak acceleration regime

Globular clusters :: new preprint

[astro-ph/0707.2459]
Using globular clusters to test gravity in the weak acceleration regime:

Authors: Riccardo Scarpa, Gianni Marconi, Roberto Gilmozzi, Giovanni Carraro

Abstract: We report on the results from an ongoing program aimed at testing Newton’s law of gravity in the low acceleration regime using globular clusters. It is shown that all clusters studied so far do behave like galaxies, that is, their velocity dispersion profile flattens out at large radii where the acceleration of gravity goes below 1e-8 cm/s/s, instead of following the expected Keplerian fall off. In galaxies this behavior is ascribed to the existence of a dark matter halo. Globular clusters, however, do not contain dark matter, hence this result might indicate that our present understanding of gravity in the weak regime of accelerations is incomplete and somehow incorrect.

(As published on the European Southern Observatory “the Messenger”, Num. 128, June 2007. Seven pages, 4 figures, 2 tables)

http://babbage.sissa.it/abs/0707.2459