sci.physics.research

Thus spake Richard Saam
>DRLunsford wrote:
>> See this paper by Scarpa et. al.
>> /abs/
>> Quoting abstract:
>> "**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**"
>
>How is it concluded that Globular clusters
>"do not contain dark matter"
>if they have the "dark matter" characteristic related to
>"velocity dispersion profile flattens out at large radii"?
>
Dark matter is generally assumed diffuse in galactic haloes - the size
of the galaxy being enough to provide the required mass. Globular
clusters are orders of magnitude smaller than galaxies and would require
large concentrations of dark matter to generate the velocity dispersion
profile. I would think that this could be eliminated by looking at the
gravitational effect of the cluster on surrounding galactic stars.

Regards

--
Charles Francis
moderator .
substitute charles for NotI to email