Related papers: C-19 and Hot, Wide, Star Streams
The shallow faint-end slope of the galaxy mass function is usually reproduced in $\Lambda$CDM galaxy formation models by assuming that the fraction of baryons that turns into stars drops steeply with decreasing halo mass and essentially…
Stellar streams retain a memory of their gravitational interactions with small-scale perturbations. While perturbative models for streams have been formulated in action-angle coordinates, a direct transformation to these coordinates is only…
In the hierarchical formation scenario in which the outer halo of the Milky Way is the result of the continuous accretion of low-mass galaxies, a fraction of the Galactic globular cluster system might have originated in and been accreted…
By means of direct N-body simulations and simplified numerical models, we study the formation and characteristics of the tidal tails around Palomar 5, along its orbit in the Milky Way potential. Unlike previous findings, we are able to…
NGC 3311 is the central cD galaxy of the Hydra I cluster. We use globular clusters around NGC 3311, combined with kinematical data of the galaxy itself, to investigate the dark matter distribution in the central region of Hydra I. Radial…
We present evidence for a new Milky Way stellar tidal stream in the direction of the Andromeda and Triangulum (M31 and M33) galaxies. Using a matched-filter technique, we search the Sloan Digital Sky Survey Data Release 8 by creating…
We explore the kinematics and orbital properties of a sample of red giants in the halo system of the Milky Way that are thought to have formed in globular clusters, based on their anomalously strong UV/blue CN bands. The orbital parameters…
The Circumgalactic Medium (CGM) of late-type galaxies is characterized using UV spectroscopy of 11 targeted QSO/galaxy pairs at z < 0.02 with the Hubble Space Telescope Cosmic Origins Spectrograph and ~60 serendipitous absorber/galaxy pairs…
A special purpose N-body simulation has been built to understand the tidal heating of the smallest dark matter substructures ($10^{-6}\msun$ and 0.01pc) from the grainy potential of the Milky Way due to individual stars in the disk and the…
NGC 2419 is one of the remotest star clusters in the Milky Way halo and its exact nature is yet unclear: While it has traits reminiscent of a globular cluster (GC), its large radius and suggestions of an abundance spread have fueled the…
Precise radial velocity measurements from HIRES on the Keck I telescope are presented for 40 stars in the outer halo globular cluster NGC 2419. These data are used to probe the cluster's stellar mass function and search for the presence of…
Collisionless dark matter galactic halos are expected to exhibit damped oscillations as a result of ongoing late time accretion. An n-body model of the cosmological assembly of a Milky Way-like halo is used to quantify the time dependence…
The properties of the Magellanic Stream constrain the density of coronal gas in the distant Galactic halo. We show that motion through ambient gas can strongly heat Stream clouds, driving mass loss and causing evaporation. If the ambient…
We develop statistical methods for identifying star streams in the halo of the Milky Way galaxy that exploit observed spatial and radial velocity distributions. Within a great circle, departures of the observed spatial distribution from…
A fundamental prediction of the Lambda Cold Dark Matter (LCDM) cosmology is the centrally divergent cuspy density profile of dark matter haloes. Density cusps render CDM haloes resilient to tides, and protect dwarf galaxies embedded in them…
We report the discovery of a young (${\rm age} \sim 130~{\rm Myr}$), low-mass ($M \sim 1200~{\rm M}_\odot$), metal-poor ($[{\rm Fe}/{\rm H}] \sim -1.1$) stellar association at a heliocentric distance $D \approx 29~{\rm kpc}$, placing it far…
Ample observational capabilities exist today to detect the small density perturbations that low-mass dark matter subhaloes impart on stellar streams from disrupting Galactic satellites. In anticipation of these observations, we investigate…
The formation of intracluster light and of the extended halos around brightest cluster galaxies is closely related to morphological transformation, tidal stripping, and disruption of galaxies in clusters. We analyze Ks- and V-band surface…
CDM simulations predict that there are hundreds of lumps of with masses greater than 10e7 solar masses in the Milky Way halo. However, we know of only a dozen dwarf satellites close to this mass. Are these lumps simply lacking in stars or…
We present radial velocities for five member stars of the recently discovered young (age= 100-150 Myr) stellar system Price-Whelan 1 (PW 1), that is located far away in the Galactic Halo (D~ 29 kpc, Z~ 15 kpc), and that is probably…