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Most of what we know about the formation of stars, and essentially everything we know about the formation of planets, comes from observations of our solar neighborhood within 2 kpc of the Sun. Before 2018, accurate distance measurements…

Astrophysics of Galaxies · Physics 2023-08-28 Catherine Zucker , João Alves , Alyssa Goodman , Stefan Meingast , Phillip Galli

We use Gaia DR2 astrometric and line-of-sight velocity information combined with two sets of distances obtained with a Bayesian inference method to study the 3D velocity distribution in the Milky Way disc. We search for variations in all…

New and more reliable distances and proper motions of a large number of stars in the Tycho-Gaia Astrometric Solution (TGAS) catalogue allow to calculate the local matter density distribution more precisely than earlier. We devised a method…

Astrophysics of Galaxies · Physics 2017-11-15 Rain Kipper , Elmo Tempel , Peeter Tenjes

Using a new algorithm for estimating the actions of orbits a parametrised distribution function is automatically fitted to observational data for the solar neighbourhood. We adopt a gravitational potential that is generated by three discs…

Astrophysics of Galaxies · Physics 2015-06-05 James Binney

We have investigated the distributions of stellar azimuthal and radial velocity components $V_{\Phi}$ and $V_{R}$ in the vertical position-velocity plane $Z$-$V_{Z}$ across the Galactic disc of $6.34 \lesssim R \lesssim 12.34$\,kpc and…

Astrophysics of Galaxies · Physics 2019-05-29 C. Wang , Y. Huang , H. -B. Yuan , M. -S. Xiang , B. -Q. Chen , H. -F. Wang , Y. -Q. Wu , H. -W. Zhang , Z. -J. Tian , Y. Yang , M. Zhang , X. -W. Liu

We examine the idea that dynamical parameters can be estimated by identifying locations in the solar neighbourhood where simulated velocity distributions match the observed local distribution. Here, the dynamical influence of both the…

Astrophysics · Physics 2009-11-13 Dalia Chakrabarty

We present a new approach for quantifying the abundance of galaxy clusters and constraining cosmological parameters using dynamical measurements. In the standard method, galaxy line-of-sight (LOS) velocities, $v$, or velocity dispersions…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-25 M. Ntampaka , H. Trac , J. Cisewski , L. C. Price

We present an updated version of the semi-analytic Just-Jahrei{\ss} (JJ) model of the Galactic disk and constrain its parameters in the Solar neighbourhood. The new features of the JJ model include a simple two-component gaseous disk, a…

Astrophysics of Galaxies · Physics 2021-03-10 K. Sysoliatina , A. Just

Taking advantage of the Gaia DR1, we combined TGAS parallaxes with the Tycho-2 and APASS photometry to calculate the star formation history (SFH) of the solar neighbourhood within 250 pc using the colour-magnitude diagram fitting technique.…

Astrophysics of Galaxies · Physics 2018-06-13 Edouard J. Bernard

The velocity distribution of neighbouring stars is deduced from the Hipparcos proper motions. We have used a classical Schwarzschild decomposition and also developed a dynamical model for quasi-exponential stellar discs. This model is a 3-D…

Astrophysics · Physics 2007-05-23 O. Bienaymé

Gaia DR2 has revealed new small-scale and large-scale patterns in the phase-space distribution of stars in the Milky Way. In cylindrical Galactic coordinates $(R,\phi,z)$, ridge-like structures can be seen in the \vphiR{} plane and…

We apply the Velocity Distribution Function (VDF) to a sample of Sunyaev-Zel'dovich (SZ)-selected clusters, and we report preliminary cosmological constraints in the $\sigma_8$-$\Omega_m$ cosmological parameter space. The VDF is a…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-14 Michelle Ntampaka , Ken Rines , Hy Trac

Relying on the dramatic increase in the number of stars with full 6D phase-space information provided by the Gaia Data Release 3, we discover unambiguous signatures of phase-mixing in the stellar halo around the Sun. We show that for the…

We present a rigorous and practical way of constraining the Galactic potential based on the phase-space information for many individual stars. Such an approach is needed to dynamically model the data from ongoing spectroscopic surveys of…

Astrophysics of Galaxies · Physics 2015-07-10 Yuan-Sen Ting , Hans-Walter Rix , Jo Bovy , Glenn van de Ven

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…

Astrophysics of Galaxies · Physics 2025-08-21 Thor Tepper-García , Joss Bland-Hawthorn , Timothy R. Bedding , Christoph Federrath , Oscar Agertz

We present a new method for inferring the gravitational potential of the Galactic disk, using the time-varying structure of a phase-space spiral in the $(z,w)$-plane (where $z$ and $w$ represent vertical position and vertical velocity). Our…

Astrophysics of Galaxies · Physics 2021-11-30 Axel Widmark , Chervin F. P. Laporte , Pablo F. de Salas

Recent studies have shown that the passage of a massive satellite through the disk of a spiral galaxy can induce vertical wobbles in the disk and produce features such as in-plane rings and phase-space spirals. Here we analyze a…

Astrophysics of Galaxies · Physics 2019-07-10 Tim Haines , Elena D'Onghia , Benoit Famaey , Chervin Laporte , Lars Hernquist

The chemo-physical parametrisation of stellar spectra is essential for understanding the nature and evolution of stars and of Galactic stellar populations. Gaia DR3 contains the parametrisation of RVS data performed by the General Stellar…

Starting from the Gaia DR3 HR diagram, we derive the star formation history (SFH) as a function of distance from the Galactic Plane within a cylinder centred on the Sun with a 200~pc radius and spanning 1.3~kpc above and below the Galaxy's…

This paper shows how a self-consistent dynamical model can be obtained by fitting the gravitational potential of the Milky Way to the stellar kinematics and densities from Gaia data. Using the Besancon Galaxy Model we derive a potential and…