相关论文: Gravitational Potential from small-scale clusterin…

We present ClearPotential, a data-driven, three-dimensional measurement of the gravitational potential of the local Milky Way using unsupervised machine learning, without the symmetry assumptions, specific functional forms, and binning…

We present a Bayesian inference approach to estimating the cumulative mass profile and mean squared velocity profile of a globular cluster given the spatial and kinematic information of its stars. Mock globular clusters with a range of…

To evaluate a potential usually one analyzes trajectories of test particles. For the Galactic Center case astronomers use bright stars or photons, so there are two basic observational techniques to investigate a gravitational potential,…

This study is aimed at investigating the dynamic evolution of the orbits of stellar globular clusters (GCs). To integrate the orbits backward in time, the authors use models of the time-varying potentials derived from cosmological…

A new X-ray selected and X-ray flux-limited galaxy cluster sample is presented. Based on the ROSAT All-Sky Survey the 63 brightest clusters with galactic latitude |bII| >= 20 deg and flux fx(0.1-2.4 keV) >= 2 * 10^{-11} ergs/s/cm^2 have…

We consider the problem of determining the Galaxy's gravitational potential from a star catalogue. We show that orbit-based approaches to this problem suffer from unacceptable numerical noise deriving from the use of only a finite number of…

We have undertaken a long term program to measure high precision proper motions of nearby Galactic globular cluster (GC) stars using multi-epoch observations with the WFPC2 and the ACS cameras on-board the Hubble Space Telescope. The proper…

We determine the total dynamical matter density in the solar neighbourhood using the second Gaia data release (DR2). The dynamical matter density distribution is inferred in a framework of a Bayesian hierarchical model, which accounts for…

We homogeneously measured the elliptical shapes of 163 globular clusters (GCs) using the on-sky distribution of their cluster members and the third data release of the ESA mission Gaia (DR3). The astrometry enables the differentiation of…

We present GaiaHub, a publicly available tool that combines $Gaia$ measurements with $Hubble$ $Space$ $Telescope$ ($HST$) archival images to derive proper motions (PMs). It increases the scientific impact of both observatories beyond their…

We use the continuity equation to derive a method for measuring the pattern speed of the Milky Way's bar/bulge from proper motion data. The method has minimal assumptions but requires complete coverage of the non-axisymmetric component in…

We develop a method for constraining the potential of the Milky Way using stellar streams with a known progenitor. The method expresses the stream in angle-action coordinates and integrates the orbits of the stars backwards in time to…

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…

$Gaia$ DR2 has provided an unprecedented wealth of information about the positions and motions of stars in our Galaxy, and has highlighted the degree of disequilibria in the disc. As we collect data over a wider area of the disc it becomes…

Efforts to dynamically trace stars back to the now-dissolved clusters in which they formed rely implicitly on the assumption that stellar orbital actions are conserved. While this holds in a static, axisymmetric potential, it is unknown how…

We use Gaia DR2 systemic proper motions of 45 satellite galaxies to constrain the mass of the Milky Way using the scale free mass estimator of Watkins et al. (2010). We first determine the anisotropy parameter $\beta$, and the tracer…

Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order…

The theoretical basis of dark energy remains unknown and could signify a need to modify the laws of gravity on cosmological scales. In this study we investigate how the clustering and motions of galaxies can be used as probes of modified…

Typical stars in the Milky Way galaxy have velocities of hundreds of kilometres per second and experience gravitational accelerations of $\sim 10^{-10}$ m s$^{-2}$, resulting in velocity changes of a few centimetres per second over a…

The peculiar velocity distribution of cluster member galaxies provides a powerful tool to directly investigate the gravitational potentials within galaxy clusters and to test the gravity theory on megaparsec scales. We exploit spectroscopic…