ar X iv : 0 70 8 . 19 35 v 2 [ as tr o - ph ] 1 6 A ug 2 00 7 Testing modified gravity with globular cluster velocity dispersions

ar X iv : 0 70 8 . 19 35 v 3 [ as tr o - ph ] 2 7 A ug 2 00 7 Testing modified gravity with globular cluster velocity dispersions

Globular clusters (GCs) in the Milky Way have characteristic velocity dispersions that are consistent with the predictions of Newtonian gravity, and may be at odds with Modified Newtonian Dynamics (MOND) and possibly the cold dark matter model. We discuss a modified gravity (MOG) theory that can successfully model the velocity dispersions of GCs in the Galactic neighborhood. MOG produces veloci...

ar X iv : 0 70 8 . 19 35 v 1 [ as tr o - ph ] 1 4 A ug 2 00 7 Testing modified gravity with globular cluster velocity dispersions

Globular clusters in the Milky Way have characteristic velocity dispersions that are consistent with the predictions of Newtonian gravity, and may be at odds with Modified Newtonian Dynamics (MOND) and possibly the cold dark matter model. We discuss a modified gravity (MOG) theory that can successfully model the velocity dispersions of GCs in the Galactic neighborhood. MOG produces velocity dis...

ar X iv : 0 70 8 . 38 56 v 1 [ as tr o - ph ] 2 8 A ug 2 00 7 Young Star Clusters in M 31

In our study of M31’s globular cluster system with MMT/Hectospec, we have obtained high-quality spectra of 85 clusters with ages less than 1 Gyr. With the exception of Hubble V, the young cluster in NGC 205, we find that these young clusters have kinematics and spatial distribution consistent with membership in M31’s young disk. Preliminary estimates of the cluster masses and structural paramet...

ar X iv : 0 70 8 . 26 18 v 1 [ as tr o - ph ] 2 0 A ug 2 00 7 Using Local Volume data to constrain Dark Matter dynamics

ar X iv : 0 70 8 . 00 96 v 1 [ as tr o - ph ] 1 A ug 2 00 7 Abundances on the Main Sequence of Omega Centauri

Abundance ratios of carbon, nitrogen and strontium relative to iron, calculated using spectrum synthesis techniques, are given for a sample of main sequence and turnoff stars that belong to the globular cluster ω Centauri. The variations of carbon, nitrogen and/or strontium show several different abundance patterns as a function of [Fe/H]. The source of the enhancements/depletions in carbon, ni...