Bibcode
Scarpa, Riccardo; Marconi, Gianni; Gilmozzi, Roberto
Bibliographical reference
1st CRISIS IN COSMOLOGY CONFERENCE, CCC-1. AIP Conference Proceedings, Volume 822, pp. 102-104 (2006).
Advertised on:
3
2006
Citations
6
Refereed citations
4
Description
Non-baryonic Dark Matter (DM) appears in galaxies and other cosmic
structures when and only when the acceleration of gravity, as computed
considering only baryons, goes below a well defined value a0 = 1.2
× 10-8 cm s-2. This fact is extremely
important and suggestive of the possibility of a breakdown of Newton's
law of gravity (or inertia) below a0. It is therefore important to
verify whether Newton's law of gravity holds in this regime of
accelerations. In order to do this, one has to study the dynamics of
objects that do not contain significant amounts of DM and therefore
should follow Newton's prediction for whatever small accelerations.
Globular clusters are believed, even by strong supporters of DM, to
contain negligible amounts of DM and therefore are ideal for testing
Newtonian dynamics in the low acceleration limit. Here, we discuss the
status of an ongoing program aimed to do this test. Compared to other
studies of globular clsuters, the novelty is that we trace the velocity
dispersion profile of globular clusters far enough from the center to
probe gravitational accelerations well below a0. In all three clusters
studied so far the velocity dispersion is found to remain constant at
large radii rather than follow the Keplerian falloff. On average, the
flattening occurs at the radius where the cluster internal acceleration
of gravity is 1.8 +/- 0.4 × 10-8 cm s-2,
fully consistent with MOND predictions.