Bibcode
DOI
Zepf, Stephen E.; Beasley, Michael A.; Bridges, Terry J.; Hanes, David A.; Sharples, Ray M.; Ashman, Keith M.; Geisler, Doug
Referencia bibliográfica
The Astronomical Journal, Volume 120, Issue 6, pp. 2928-2937.
Fecha de publicación:
12
2000
Número de citas
71
Número de citas referidas
54
Descripción
We present new radial velocities for 87 globular clusters around the
elliptical galaxy NGC 4472 and combine these with our previously
published data to create a data set of velocities for 144 globular
clusters around NGC 4472. We utilize this data set to analyze the
kinematics of the NGC 4472 globular cluster system. The new data confirm
our previous discovery that the metal-poor clusters have significantly
higher velocity dispersion than the metal-rich clusters in NGC 4472. We
also find very little or no rotation in the more spatially concentrated
metal-rich population, with a resulting upper limit for this population
of (v/σ)proj<0.34 at a 99% confidence level. The
very small angular momentum in the metal-rich population requires
efficient angular momentum transport during the formation of this
population, which is spatially concentrated and chemically enriched.
Such angular momentum transfer can be provided by galaxy mergers, but it
has not been achieved in other extant models of elliptical galaxy
formation that include dark matter halos. We also calculate the velocity
dispersion as a function of radius and show that it is consistent with
roughly isotropic orbits for the clusters and the mass distribution of
NGC 4472 inferred from X-ray observations of the hot gas around the
galaxy.