Related papers: A fully cosmological model of a Monoceros-like rin…
We examine metallicities, ages and orbital properties of halo stars in a Milky-Way like disk galaxy formed in the cosmological hydrodynamical MaGICC simulations. Halo stars were either accreted from satellites or they formed in situ in the…
Context. Gas within a galaxy is forced to establish pressure balance against gravitational forces. The shape of an unperturbed gaseous disk can be used to constrain dark matter models. Aims. We derive the 3-D HI volume density distribution…
We analyse a 10,000 star spectroscopic survey, focused on Galactic thick disk stars typically 2-5 kpc from the Sun, carried out using the AAOmega Spectrograph on the AAT. We develop methods for completeness-correction of the survey based on…
We study the kinematics of satellites around isolated galaxies selected from the Sloan Digital Sky Survey (SDSS) spectroscopic catalog. Using a model of the phase-space density previously measured for the halos of LCDM dark matter…
Recently, Widrow and collaborators announced the discovery of vertical density waves in the Milky Way disk. Here we investigate a scenario where these waves were induced by the Sagittarius dwarf galaxy as it plunged through the Galaxy.…
We use numerical simulations to examine the substructure within galactic and cluster mass halos that form within a hierarchical universe. Clusters are easily reproduced with a steep mass spectrum of thousands of substructure clumps that…
We use a suite of numerical simulations to investigate the mechanisms and effects of radial migration of stars in disk galaxies like the Milky Way (MW). An isolated, collisionless stellar disk with a MW-like scale-height shows only the…
We provide a set of numerical N-body simulations for studying the formation of the outer Milky Ways's stellar halo through accretion events. After simulating minor mergers of prograde and retrograde orbiting satellite halo with a Dark…
We investigate the formation of multiple spiral modes in Milky Way-like disk-halo systems without explicitly exciting perturbations. We explore how numerical resolution, the level of local disk stability, and the presence of a live halo…
Using radio polarimetry we study the connection between the transport of cosmic rays (CR's), the three-dimensional magnetic field structure, and features of other ISM phases in the halo of NGC 253. We present a new sensitive radio continuum…
Aims. We aim to show how encounters with low-mass satellite galaxies may alter the bar formation in a Milky Way-like disc galaxy. Methods. We use high-resolution N-body simulations of a disc galaxy prone to mild bar instability. For…
The formation mechanism of the hot gaseous halo associated with the Milky Way Galaxy is still under debate. We report new observational constraints on the gaseous halo using 107 lines-of-sight of the Suzaku X-ray observations at…
The spatial distribution of the satellite populations of the Milky Way and Andromeda are puzzling in that they are nearly perpendicular to the disks of their central galaxies. To understand the origin of such configurations we study the…
(Shortened) We observed NGC 253 with the VLA in D-configuration and the Effelsberg 100-m telescope using radio continuum polarimetry. Observations at 6.2 cm and 3.6 cm were combined to calculate the RM distribution and to correct for…
We study the properties of satellites in the environment of massive star-forming galaxies at z~1.8 in the COSMOS field, using a sample of 215 galaxies on the main sequence of star formation with an average mass of 10^11 Msun. At z>1.5,…
High-Velocity Clouds (HVCs) are a major fuel reservoir for star formation in the Galactic disk. Determining their origin and kinematics is thus crucial for understanding Galactic evolution. In this paper, we employ simple test-particle…
Using a new, expanded compilation of extragalactic source Faraday rotation measures (RM) we investigate the broad underlying magnetic structure of the Galactic disk at latitudes $|b|$ $\lesssim 15^{\circ}$ over all longitudes $l$, where our…
We use extensive gravity-sensitive DDO 51 photometry over 5100 square degrees, combined with SDSS broadband photometry, to select a catalog of $\sim 4,000$ giant stars covering a large fraction of the high Galactic latitude sky and reaching…
A theory is developed for the dynamics of eccentric perturbations $[\propto \exp(\pm i\phi)]$ of a disk galaxy residing in a spherical dark matter halo and including a spherical bulge component. The disk is represented as a large number $N$…
Using the 100-m radio telescope at Effelsberg, we mapped a large area around the Andromeda Galaxy in the 21-cm line emission of neutral hydrogen to search for high-velocity clouds (HVCs) out to large projected distances in excess of 100…