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Related papers: Quantifying torque from the Milky Way bar using Ga…

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We use numerical simulations to model Gaia DR3 data with the aim of constraining the Milky Way bar and spiral structure parameters. We show that both the morphology and the velocity field in Milky Way-like galactic disc models are strong…

The Milky Way (MW) hosts a central bar whose pattern speed, orientation, and length remain uncertain, largely due to observational biases and selection effects, despite the transformative data provided by the Gaia mission. We aim to…

We have mapped the number density and mean vertical velocity of the Milky Way's stellar disk out to roughly two kiloparsecs from the Sun using Gaia Data Release 3 (DR3) and complementary photo-astrometric distance information from…

Astrophysics of Galaxies · Physics 2022-12-14 Axel Widmark , Lawrence M. Widrow , Aneesh Naik

We use low-amplitude, long period variable (LA-LPV) candidates in \textit{Gaia} DR3 to trace the kinematics and dynamics of the Milky Way bar. LA-LPVs, like other LPVs, are intrinsically bright and follow a tight period-luminosity relation,…

Astrophysics of Galaxies · Physics 2024-12-20 Hanyuan Zhang , Vasily Belokurov , N. Wyn Evans , Sarah G. Kane , Jason L. Sanders

In this paper we introduce a new method for analysing Milky Way phase-space which allows us to reveal the imprint left by the Milky Way bar and spiral arms on the stars with full phase-space data in Gaia Data Release 2. The unprecedented…

Astrophysics of Galaxies · Physics 2020-02-05 S. Khoperskov , O. Gerhard , P. Di Matteo , M. Haywood , D. Katz , S. Khrapov , A. Khoperskov , M. Arnaboldi

The dynamical effects on the stellar motion produced by the Galactic central bar and the spiral arms perturbations are investigated separately and compared. The stars from the Gaia DR3 catalog are selected in the region of observable…

Astrophysics of Galaxies · Physics 2026-03-03 Willian Y. Nacafucasaco , Tatiana A. Michtchenko , Douglas Barros , Jacques Lépine

Spectroscopic surveys now supply precise stellar label measurements such as element abundances for large samples of stars throughout the Milky Way. These element abundances are known to correlate with orbital actions or other dynamical…

In the fundamental quest of the rotation curve of the Milky Way, the tangent-point (TP) method has long been the simplest way to infer velocities for the inner, low latitude regions of the Galactic disk from observations of the gas…

Astrophysics of Galaxies · Physics 2015-06-03 Laurent Chemin , Florent Renaud , Caroline Soubiran

We present a novel method for constraining the length of the Galactic bar using 6D phase space information to directly integrate orbits. We define a pseudo-length for the Galactic bar, named $R_{Freq}$, based on the maximal extent of…

Action space synthesizes the orbital information of stars and is well-suited to analyse the rich kinematic substructure of the disc in the \emph{Gaia} DR2 radial velocity sample (RVS). We revisit the strong perturbation induced in the Milky…

Astrophysics of Galaxies · Physics 2021-11-29 Wilma H. Trick , Francesca Fragkoudi , Jason A. S. Hunt , J. Ted Mackereth , Simon D. M. White

Previous work has related the Galactic bar to structure in the local stellar velocity distribution. Here we show that the bar also influences the spatial gradients of the velocity vector via the Oort constants. By numerical integration of…

Astrophysics of Galaxies · Physics 2010-02-10 Ivan Minchev , Jason Nordhaus , Alice Quillen

We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using $\chi^2$ minimisation, we find that the best-fit Galactic bar model has a pattern speed $\Omega_{\rm p}=60 \rm{km s^{-1}…

Astrophysics of Galaxies · Physics 2015-06-11 Yougang Wang , Hongsheng Zhao , Shude Mao , R. M. Rich

The second data release of the Gaia mission has revealed, in stellar velocity and action space, multiple ridges, the exact origin of which is still debated. Recently, we demonstrated that a large Galactic bar with pattern speed 39 km/s/kpc…

Astrophysics of Galaxies · Physics 2019-12-11 G. Monari , B. Famaey , A. Siebert , O. Bienaymé , R. Ibata , C. Wegg , O. Gerhard

Our recent studies of axial-symmetry breaking in the nearby ($d <3 \,{\rm kpc}$) star counts are sensitive to the distortions of stellar orbits perpendicular and parallel to the orientation of the bar just within and beyond the outer…

Astrophysics of Galaxies · Physics 2020-08-20 Austin Hinkel , Susan Gardner , Brian Yanny

The rotation curve (RC) of our Galaxy, the Milky Way, is constructed starting from its very inner regions (few hundred pc) out to a large Galactocentric distance of $\sim 200$ kpc using kinematical data on a variety of tracer objects moving…

Astrophysics of Galaxies · Physics 2015-06-17 Pijushpani Bhattacharjee , Soumini Chaudhury , Susmita Kundu

A model of the Galaxy with the outer ring R1R2 can explain the observed distribution of the radial, VR, and azimuthal, VT, velocity components along the Galactocentric distance, R, derived from the Gaia EDR3 data. We selected stars from the…

Astrophysics of Galaxies · Physics 2021-09-16 A. M. Melnik , A. K. Dambis , E. N. Podzolkova , L. N. Berdnikov

The Milky Way is a complex ecosystem, for which we can obtain detailed observations probing the physical mechanisms determining the interstellar medium. For a detailed comparison with observations, and to provide theories for missing…

We determine the rotation curve (RC) of the Milky Way in the range 6 < R < 18 kpc using a sample of 903 carefully selected classical Cepheids with precise proper motions and high-quality radial velocities from \emph{Gaia} DR3. Their…

Astrophysics of Galaxies · Physics 2025-12-29 Qikang Feng , Yang Huang , Huawei Zhang , Jifeng Liu

We measure the Galactic rotation curve and its first two vertical derivatives in the first and fourth quadrants of the Milky Way using the 21 cm VGPS and SGPS. We find tangent velocities of the atomic gas as a function of galactic longitude…

Astrophysics · Physics 2009-06-23 E. S. Levine , Carl Heiles , Leo Blitz

We compare distance resolved, absolute proper motions in the Milky Way bar/bulge region to a grid of made-to-measure dynamical models with well defined pattern speeds. The data are obtained by combining the relative VVV Infrared Astrometric…

Astrophysics of Galaxies · Physics 2022-04-29 Jonathan Clarke , Ortwin Gerhard