We have compiled a sample of 699 stars from the recent literature with detailed chemical abundance information (spanning −4.2 . [Fe/H] . +0.3), and we compute their space velocities and Galactic orbital parameters. We identify members of the inner and outer stellar halo populations in our sample based only on their kinematic properties and then compare the abundance ratios of these populations ...

Based on exploratory simulations, Rojas-Niño et al. (2012) have proposed that triaxiality in the Galactic dark matter halo might cause lumpiness in the velocity distribution of halo stars in the Solar Neighbourhood through orbital resonances. Accordingly, they have asserted that detecting the presence of substructures in velocity space may be a method for diagnosing the shape of the dark matter...

We correct the observed Milky Way satellite luminosity function for luminosity bias using published completeness limits for the Sloan Digital Sky Survey DR5. Assuming that the spatial distribution of Milky Way satellites tracks the subhalos found in the Via Lactea ΛCDM N-body simulation, we show that there should be between ∼ 300 and ∼ 600 satellites within 400 kpc of the Sun that are brighter ...

Our galaxy contains an interesting stream of stars that may represent the disruption of a previous small satellite galaxy as it merged with the Milky Way. Forbes et al. (p. 1217) used the Keck 10-meter telescope and the Hubble Space telescope to obtain direct evidence for such merger processes in the Tadpole Galaxy UGC 10214. They observed the stretching of the colliding dwarf galaxy into a cha...

A solution is presented for the past motions of the Magellanic Clouds, the Milky Way galaxy, and the Andromeda Nebula, fitted to the measured velocities of the Clouds and M31, under some simplifying assumptions. The galaxies are modeled as isolated bodies back to redshift about 10, when their velocities relative to the general expansion of the universe were small, consistent with the gravitatio...

We perform N-body simulations of the dynamical evolution of a dwarf galaxy falling into the Milky Way galaxy in order to understand the formation scenario of the peculiar globular cluster ω Centauri. We use self-consistent models of the bulge and the disc of the Milky Way, as well as of the dwarf galaxy, and explore a range of dwarf models with different density distributions. Namely, we use Ki...

Some of the properties of the globular clusters in NGC 5128 the nearest giant elliptical galaxy are compared to those of Galactic globular clusters. Assuming the colormetallicity relations that hold for Galactic globular clusters one finds that the metal-poor clusters in NGC 5128 that have [Fe/H] < -1.80 are significantly fainter than are the more metal-rich globulars in that galaxy. No such me...

We explore the predictions of the standard hierarchical clustering scenario of galaxy formation, regarding the numbers and metallicities of PopIII stars likely to be found within our Galaxy today. By PopIII we shall be referring to stars formed at large redshift (z > 4), with low metallicities ([Z/Z⊙] < −2.5) and in small systems (total mass < ∼ 2×10 8M⊙) that are extremely sensitive to stellar...