相关论文: Dark Galactic subhalos and the Gaia snail
We address the problem of identifying remnants of satellite galaxies in the halo of our galaxy with Gaia data. The remnants have to be extracted from a very large data set (of order 10^9 stars) in the presence of observational errors and…
The discovery of the phase space spirals in the Solar neighborhood in Gaia Data Release 2 has prompted various attempts to understand their origin. A source of bending waves, which has been neglected as a cause of the phase spiral, is…
We present a study of the shapes, orientations, and alignments of Galactic dark matter subhalos in the ``Via Lactea'' simulation of a Milky Way-size LCDM host halo. Whereas isolated dark matter halos tend to be prolate, subhalos are…
We study the shapes of subhalo distributions from four dark-matter-only simulations of Milky Way type haloes. Comparing the shapes derived from the subhalo distributions at high resolution to those of the underlying dark matter fields we…
We use the second data releases of the ESA Gaia astrometric survey and the high-resolution GALAH spectroscopic survey to analyse the structure of our Galaxy's disc components. With GALAH, we separate the alpha-rich and alpha-poor discs…
New data from the $\textit{Gaia}$ satellite, when combined with accurate photometry from the Pan-STARRS survey, allow us to accurately estimate the properties of the GD-1 stream. Here, we analyze the stellar density perturbations in the…
Tidal debris from infalling satellites can leave observable structure in the phase-space distribution of the Galactic halo. Such substructure can be manifest in the spatial and/or velocity distributions of the stars in the halo. This paper…
We use a catalogue of stellar binaries with wide separations (up to 1 pc) identified by the Gaia satellite to constrain the presence of extended substructure within the Milky Way galaxy. Heating of the binaries through repeated encounters…
We use the ``Via Lactea'' simulation to study the co-evolution of a Milky Way-size LambdaCDM halo and its subhalo population. While most of the host halo mass is accreted over the first 6 Gyr in a series of major mergers, the physical mass…
A simple model is presented of the formation of the spiral the (z,v_z) phase plane of solar-neighbourhood stars that was recently discovered in Gaia data. The key is that the frequency Omega_z at which stars oscillate vertically depends on…
We use the distribution of accreted stars in SDSS-Gaia DR2 to demonstrate that a non-trivial fraction of the dark matter halo within Galactocentric radii of 7.5-10 kpc and $|z| > 2.5$ kpc is in substructure, and thus may not be in…
Galaxies are thought to grow through accretion; as less massive galaxies are disrupted and merge over time, their debris results in diffuse, clumpy stellar halos enveloping the central galaxy. Here we present a study of the variation in the…
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 model the formation of the Galactic stellar halo via the accretion of satellite galaxies onto a time-dependent semi-cosmological galactic potential. Our goal is to characterize the substructure left by these accretion events in a close…
The Gaia satellite revealed a remarkable spiral pattern ('phase spiral', PS) in the z-Vz phase-plane throughout the solar neighbourhood, where z and Vz are the displacement and velocity of a star perpendicular to the Galactic plane. As…
In cold dark matter cosmological models, structures form and grow by merging of smaller units. Numerical simulations have shown that such merging is incomplete; the inner cores of halos survive and orbit as "subhalos" within their hosts.…
We develop an explicit model for the formation of the stellar halo from tidally disrupted, accreted dwarf satellites in the cold dark matter (CDM) framework, focusing on predictions testable with the Sloan Digital Sky Survey (SDSS) and…
The abundance of dark matter (DM) subhalos orbiting a host galaxy is a generic prediction of the cosmological framework, and is a promising way to constrain the nature of DM. In this paper, we investigate the use of machine learning-based…
In numerous studies of the outer Galactic halo some evidence for accretion has been found. If the outer halo did form in part or wholly through merger events, we might expect to find coherent streams of stars and globular clusters following…
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…