相关论文: Disassembling the Galaxy with angle-action coordin…
Action-angle coordinates are an essential tool for understanding the properties of the six dimensional phase space involved in orbits of stars in galactic potentials. A new method, which does not require specific knowledge of a generating…
The usefulness of angle-action variables in galaxy dynamics is well known, but their use is limited due to the difficulty of their calculation in realistic galaxy potentials. Here we present a method for estimating angle-action variables in…
In the currently favored cosmological paradigm galaxies form hierarchically through the accretion of numerous satellite galaxies. Since the satellites are much less massive than the host halo, they occupy a small fraction of the volume in…
We employ high-resolution N-body simulations of isolated spiral galaxy models, from low-amplitude, multi-armed galaxies to Milky Way-like disks, to estimate the vertical action of ensembles of stars in an axisymmetric potential. In the…
Galaxy surveys aim to map the large-scale structure of the Universe and use redshift space distortions to constrain deviations from general relativity and probe the existence of massive neutrinos. However, the amount of information that can…
We show that the kinematics of the shells seen around some elliptical galaxies provide a new, independent means for measuring the gravitational potentials of elliptical galaxies out to large radii. A numerical simulation of a set of shells…
Near-future surveys promise a dramatic improvement in the number and precision of astrometric, photometric and spectroscopic measurements of stars in the Milky Way's disk. We examine the impact of such surveys on our understanding of the…
Analysis of the peculiar velocities of galaxies should take account of the uncertainties in both redshifts and distances. We show how this can be done by a numerical application of the action principle. The method is applied to an improved…
We introduce methods which allow observed galaxy clustering to be used together with observed luminosity or stellar mass functions to constrain the physics of galaxy formation. We show how the projected two-point correlation function of…
We have reconstructed possible orbits for a collection of stars located within 0.5 arcsec of Sgr A*. These orbits are constrained by observed stellar positions and angular proper motions. The construction of such orbits serves as a baseline…
The combination of dynamical and photometric properties of galaxies offers a largely un-tapped source of information on how galaxies assembled and where stars formed. Bi-dimensional kinematic measurements have been the stumbling block. The…
Clues to the origins and evolution of our Galaxy can be found in the kinematics of stars around us. Remnants of accreted satellite galaxies produce over- densities in velocity-space, which can remain coherent for much longer than spatial…
We present a method for extracting actions, angles and frequencies from an orbit's time series. The method recovers the generating function that maps an analytic phase-space torus to the torus to which the orbit is confined by…
Our understanding of how the Galaxy was formed and evolves is severely hampered by the lack of precise constraints on basic stellar properties such as distances, masses, and ages. Here, we show that solar-like pulsating red giants represent…
The quality and quantity of 6D stellar position-velocity measurements in the second Gaia data release (DR2) allows to study small-scale structure in the orbit distribution of the Galactic disc beyond the immediate Solar neighborhood. We…
We present a method to constrain the potential of the non-axisymmetric components of the Galaxy using the kinematics of stars in the solar neighborhood. The basic premise is that dynamical substructures in phase-space (i.e. due to the bar…
We use numerical simulations to investigate the orbital characteristics of tidal debris from satellites whose orbits are dragged into the plane of galactic disks by dynamical friction before disruption. We find that these satellites may…
Analytical and numerical galaxy-formation models indicate that active galactic nuclei (AGNs) likely play a prominent role in the formation and evolution of galaxies. However, quantifying this effect requires knowledge of how the nuclear…
Stars near the Sun oscillate both horizontally and vertically. In Paper I the coupling between these motions was modelled by determining the horizontal motion without reference to the vertical motion, and recovering the coupling by assuming…
We try to determine the Galactic structure by comparing the observed and modeled velocities of OB-associations in the 3 kpc solar neighborhood. We made N-body simulations with a rotating stellar bar. The galactic disk in our model includes…