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We simultaneously model the gravitational potential and phase space distribution function (DF) of giant stars near the Sun using the {\it Gaia} DR2 radial velocity catalog. We assume that the Galaxy is in equilibrium and is symmetric about…

Astrophysics of Galaxies · Physics 2023-02-01 Haochuan Li , Lawrence Widrow

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…

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…

Astrophysics of Galaxies · Physics 2019-02-27 Axel Widmark

We have applied our method for weighing the Galactic disk using phase-space spirals to the Gaia EDR3 proper motion sample. For stars in distant regions of the Galactic disk, the latitudinal proper motion has a close projection with vertical…

Astrophysics of Galaxies · Physics 2022-07-06 Axel Widmark , Chervin F. P. Laporte , Giacomo Monari

{\it Gaia} Data Release 2 (DR2) revealed that the Milky Way contains significant indications of departures from equilibrium in the form of asymmetric features in the phase space density of stars in the Solar neighborhood. One such feature…

Astrophysics of Galaxies · Physics 2022-07-28 Jason A. S. Hunt , Adrian M. Price-Whelan , Kathryn V. Johnston , Elise Darragh-Ford

The vertical structure and dynamics of stars in our local Galactic neighbourhood contains much information about the local distribution of visible and dark matter and of perturbations to the Milky Way disc. We use data on the positions and…

Astrophysics of Galaxies · Physics 2018-11-08 Morgan Bennett , Jo Bovy

We discuss the physical mechanism by which pure vertical bending waves in a stellar disc evolve to form phase space spirals similar to those discovered by Antoja et al. ( arXiv:1804.10196) in Gaia Data Release 2. These spirals were found by…

Astrophysics of Galaxies · Physics 2019-01-01 Keir Darling , Lawrence M. Widrow

The second data release of ESA's $Gaia$ mission revealed numerous signatures of disequilibrium in the Milky Way's disc. These signatures are seen in the planar kinematics of stars, which manifest as ridges and ripples in $R-v_{\phi}$, and…

We determine the total dynamical density in the solar neighbourhood using the Tycho-Gaia Astrometric Solution (TGAS) catalogue. Astrometric measurements of proper motion and parallax of stars inform us of both the stellar number density…

Astrophysics of Galaxies · Physics 2019-11-04 Axel Widmark , Giacomo Monari

By taking advantage of the superb measurements of position and velocity for an unprecedented large number of stars provided in Gaia DR2, we have generated the first maps of the rotation velocity, $V_{\rm rot}$, and vertical velocity,…

Astrophysics of Galaxies · Physics 2018-06-27 Daisuke Kawata , Junichi Baba , Ioana Ciucă , Mark Cropper , Robert J. J. Grand , Jason A. S. Hunt , George Seabroke

The absolute number and the density profiles of different types of stars in the solar neighborhood are a fundamental anchor for studies of the initial mass function, stellar evolution, and galactic structure. Using data from the Gaia DR1…

Astrophysics of Galaxies · Physics 2017-07-17 Jo Bovy

The stellar velocity distribution function (DF) in the solar vicinity is re-examined using data from the SDSS APOGEE survey's DR16 and \emph{Gaia} DR2. By exploiting APOGEE's ability to chemically discriminate with great reliability the…

The vertical distribution of stars in the solar neighbourhood is not in equilibrium but contains a wave signature in both density and velocity space originating from a perturbation. With the discovery of the phase-space spiral in Gaia data…

Astrophysics of Galaxies · Physics 2021-06-15 Morgan Bennett , Jo Bovy

Disc stars from the Gaia DR3 RVS catalogue are selected to explore the phase spiral as a function of position in the Galaxy. The data reveal a two-armed phase spiral pattern in the local $z-v_z$ plane inside the solar radius, which appears…

Astrophysics of Galaxies · Physics 2023-08-02 Chengdong Li , Arnaud Siebert , Giacomo Monari , Benoit Famaey , Simon Rozier

We compare the distribution in position and velocity of nearby stars from the Gaia DR2 radial velocity sample with predictions of current theories for spirals in disc galaxies. Although the rich substructure in velocity space contains the…

Astrophysics of Galaxies · Physics 2019-01-23 J. A. Sellwood , Wilma Trick , Ray Carlberg , Johanna Coronado , Hans-Walter Rix

In 2018, the ESA \Gaia\ satellite discovered a remarkable spiral pattern ("phase spiral") in the $z-V_z$ phase plane throughout the solar neighbourhood, where $z$ and $V_z$ are the displacement and velocity of a star perpendicular to the…

Astrophysics of Galaxies · Physics 2021-03-17 Joss Bland-Hawthorn , Thor Tepper-Garcia

A seven-parameter distribution function (DF) is fitted to $20\,000$ RR-Lyrae stars for which only astrometric data are available. The observational data are predicted by the DF in conjunction with the gravitational potential of a…

Astrophysics of Galaxies · Physics 2022-01-05 Chengdong Li , James Binney

The young disc vertical phase is paramount in our understanding of Galaxy evolution. Analysing the vertical kinematics at different galactic regions provides important information about the space-time variations of the Galactic potential.…

Astrophysics of Galaxies · Physics 2025-01-10 Emilio J. Alfaro , M Carmen Sánchez Gil , Bruce Elmegreen

We investigate the spatiotemporal structure of simulations of the homogeneous slab and isothermal plane models for the vertical motion in the Galactic disc. We use Dynamic Mode Decomposition (DMD) to compute eigenfunctions of the simulated…

Astrophysics of Galaxies · Physics 2019-09-17 Keir Darling , Lawrence M. Widrow

We infer the gravitational potential of the Galactic disk by analysing the phase-space densities of 120 stellar samples in 40 spatially separate sub-regions of the solar neighbourhood, using Gaia's second data release (DR2), in order to…

Astrophysics of Galaxies · Physics 2021-02-10 Axel Widmark , Pablo Fernández de Salas , Giacomo Monari
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