Related papers: Hidden depths in the local Universe: The Stellar S…
The concordance Lambda Cold Dark Matter (Lambda-CDM) model for the formation of structure in the Universe, while remarkably successful at describing observations of structure on large scales, continues to be challenged by observations on…
Stellar streams offer one of the most sensitive probes of the Milky Way`s gravitational potential, as their phase-space morphology encodes both the tidal field of the host galaxy and the internal structure of their progenitors. In this…
Recent observations have revealed streams of gas and stars in the halo of the Milky Way that are the debris from interactions between our Galaxy and some of its dwarf companion galaxies; the Sagittarius dwarf galaxy and the Magellanic…
Stellar shells are low surface brightness features, created during nearly head-on galaxy mergers from the debris of the tidally disrupted satellite. Here, we investigate the formation and evolution mechanism of shells in six dimensions (3d…
We describe a technique that finds orbits through the Galaxy that are consistent with measurements of a tidal stream, taking into account the extent that tidal streams do not precisely delineate orbits. We show that if accurate…
Tidal structures around globular clusters provide valuable insights into cluster evolution and the hierarchical assembly of the Milky Way. Using wide-field imaging data from the DESI Legacy Survey combined with a color-magnitude…
We have probed a section (l ~ 150, b ~ -60) of the trailing tidal arm of the Sagittarius dwarf spheroidal galaxy by identifying a sample of Red Clump stream stars. Red Clump stars are not generally found in the halo field, but are found in…
We have designed a powerful new algorithm to detect stellar streams in an automated and systematic way. The algorithm, which we call the STREAMFINDER, is well suited for finding dynamically cold and thin stream structures that may lie along…
We present the analysis of 1,207 RR Lyrae found in photometry taken by the Catalina Survey's Mount Lemmon telescope. By combining accurate distances for these stars with measurements for ~14,000 type-AB RR Lyrae from the Catalina Schmid…
Amateur small equipment has demonstrated to be competitive tools to obtain ultra-deep imaging of the outskirts of nearby massive galaxies and to survey vast areas of the sky with unprecedented depth. Over the last decade, amateur data have…
The Milky Way's satellites provide unique information about the density of the Galactic halo at large radii. The inclusion of even a few rather inaccurate proper motions resolves an ambiguity in older mass estimates in favour of higher…
To enhance our understanding of the impact of galaxy mergers on the kinematics of early-type galaxies (ETGs), we examine differences in specific stellar angular momentum within the half-light radius ($\lambda_{R_e}$) among ETGs with…
Deep color magnitude diagrams extending to the main sequence provide the most direct measure of the detailed star formation history in a stellar population. With large investments of observing time, HST can obtain such data for populations…
We are carrying out a comprehensive multi-wavelength study of dwarf galaxies in the Local Volume (< 5 Mpc). After our all-sky survey more than doubled the dwarf census we are now measuring structural parameters, integrated properties, and…
In recent years the census of known satellites in our own Local Group and in nearby galaxy groups has increased substantially due to sensitive wide-area surveys. In the Local Group these surveys have more than doubled its known galaxy…
As part of the Z-PAndAS Keck II DEIMOS survey of resolved stars in our neighboring galaxy, Andromeda (M31), we have built up a unique data set of measured velocities and chemistries for thousands of stars in the Andromeda stellar halo,…
We have searched for in-falling stellar streams on to the local Milky Way disc in the CORAVEL and RAVE surveys. The CORAVEL survey consists of local dwarf stars (Nordstrom et al. Geneva-Copenhagen survey) and local Famaey et al. giant…
The study of dynamically cold stellar streams reveals information about the gravitational potential where they reside and provides important constraints on dark matter properties. However, their intrinsic faintness makes detection beyond…
Within the Local Universe galaxies can be studied in great detail star by star, and here we review the results of quantitative studies in nearby dwarf galaxies. The Color-Magnitude Diagram synthesis method is well established as the most…
Cold or Warm, the Dark Matter substructure spectrum must extend to objects with masses as low as $10^7 M_\odot$, according to the most recent Lyman-$\alpha$ measurements. Around a Milky Way-like galaxy, more than a thousand of these…