Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-11-22
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
Accepted for publication in ApJ
Scientific paper
We explore whether global observed properties, specifically half-light radii, mean surface brightness, and integrated stellar kinematics, suffice to unambiguously differentiate galaxies from star clusters, which presumably formed differently and lack dark matter halos. We find that star clusters lie on the galaxy scaling relationship referred to as the Fundamental Manifold (FM), on the extension of a sequence of compact galaxies, and so conclude that there is no simple way to differentiate star clusters from ultra-compact galaxies. By extending the validity of the FM over a larger range of parameter space and a wider set of objects, we demonstrate that the physics that constrains the resulting baryon and dark matter distributions in stellar systems is more general than previously appreciated. The generality of the FM implies 1) that the stellar spatial distribution and kinematics of one type of stellar system do not arise solely from a process particular to that set of systems, such as violent relaxation for elliptical galaxies, but are instead the result of an interplay of all processes responsible for the generic settling of baryons in gravitational potential wells, 2) that the physics of how baryons settle is independent of whether the system is embedded within a dark matter halo, and 3) that peculiar initial conditions at formation or stochastic events during evolution do not ultimately disturb the overall regularity of baryonic settling. We also utilize the relatively simple nature of star clusters to relate deviations from the FM to the age of the stellar population and find that stellar population models systematically and significantly over predict the mass-to-light ratios of old, metal-rich clusters.
Gonzalez Anthony H.
Zabludoff Ann I.
Zaritsky Dennis
No associations
LandOfFree
Star Clusters, Galaxies, and the Fundamental Manifold does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Star Clusters, Galaxies, and the Fundamental Manifold, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Star Clusters, Galaxies, and the Fundamental Manifold will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-586476