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Related papers: New Constraints on the Galactic Bar

200 papers

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

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 spatial variations of the velocity field of local stars provide direct evidence of Galactic differential rotation. The local divergence, shear, and vorticity of the velocity field---the traditional Oort constants---can be measured based…

Astrophysics of Galaxies · Physics 2017-04-18 Jo Bovy

Aims: We investigate whether the cylindrical (galactocentric) radial velocity gradient of ~ -3 km/s/kpc, directed radially from the Galactic center and recently observed in the stars of the solar neighborhood with the RAVE survey, can be…

Astrophysics of Galaxies · Physics 2014-10-01 Giacomo Monari , Amina Helmi , Teresa Antoja , Matthias Steinmetz

We perform test-particle simulations in a 2D, differentially rotating stellar disk, subjected to a two-armed steady state spiral density wave perturbation in order to estimate the influence of spiral structure on the local velocity field.…

Astrophysics · Physics 2008-11-26 I. Minchev , A. Quillen

It has been suggested that a resonance between a rotating bar and stars in the solar neighbourhood can produce the so called 'Hercules stream'. Recently, a second bar may have been identified in the Galactic centre, the so called 'long…

Astrophysics of Galaxies · Physics 2010-05-25 Esko Gardner , Chris Flynn

We study the kinematics of stellar disc populations within the solar neighbourhood in order to find the imprints of the Galactic bar. We carry out the analysis by developing a numerical resolution of the 2D2V Collisionless Boltzmann…

Astrophysics of Galaxies · Physics 2018-05-16 Olivier Bienaymé

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

Most late-type stars in the solar neighborhood have velocities similar to the local standard of rest (LSR), but there is a clearly separated secondary component corresponding to a slower rotation and a mean outward motion. Detailed…

Astrophysics · Physics 2009-10-31 Walter Dehnen

The local stellar kinematics of the Milky Way offer a useful tool for studying the rotation curve of the Galaxy. These kinematics -- usually parameterized by the Oort constants A and B -- depend on the local gradient of the rotation curve…

Astrophysics · Physics 2009-10-30 R. P. Olling , M. R. Merrifield

We study the late-time evolution of the central regions of two Milky Way-like simulations of galaxies formed in a cosmological context, one hosting a fast bar and the other a slow one. We find that bar length, R_b, measurements fluctuate on…

(Abridged) The Galactic bar causes a characteristic splitting of the disc phase space into regular and chaotic orbit regions which is shown to play an important role in shaping the stellar velocity distribution in the Solar neighbourhood. A…

Astrophysics · Physics 2009-06-16 R. Fux

Using available kinematical data for a subsample of NLTT stars from the HIPPARCOS mission we confirm the existence of a previously reported local anomaly in the (u,v) plane: the mean motion u for old disc stars, with v < -30 km/s, is…

Astrophysics · Physics 2007-05-23 D. Raboud , M. Grenon , L. Martinet , R. Fux , S. Udry

The paper is devoted to the analysis of the influence of the galactic bar on the nature of the orbital motion (chaotic or regular) of globular clusters in the central region of the Galaxy with a radius of 3.5 kpc, which are subject to the…

Astrophysics of Galaxies · Physics 2024-12-04 Anisa Bajkova , Anton Smirnov , Vadim Bobylev

We use compiled high-precision pulsar timing measurements to directly measure the Galactic acceleration of binary pulsars relative to the Solar System barycenter. Given the vertical accelerations, we use the Poisson equation to derive the…

Astrophysics of Galaxies · Physics 2021-03-17 Sukanya Chakrabarti , Philip Chang , Michael T. Lam , Sarah J. Vigeland , Alice C. Quillen

Non-axisymmetries in the Galactic potential (spiral arms and bar) induce kinematic groups such as the Hercules stream. Assuming that Hercules is caused by the effects of the Outer Lindblad Resonance of the Galactic bar, we model…

One of the main properties of galactic bars is their rotation (or pattern) speed, which is driven by both internal galactic properties, as well as external interactions. To assess the influence of these internal and external drivers on bar…

Astrophysics of Galaxies · Physics 2026-01-30 Alex Merrow , Francesca Fragkoudi , Rob J. J. Grand , Marie Martig

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…

Astrophysics of Galaxies · Physics 2015-05-19 Pertti Rautiainen , Anna Mel'nik

We provide the first quantitative evidence for the deceleration of the Galactic bar from local stellar kinematics in agreement with dynamical friction by a typical dark matter halo. The kinematic response of the stellar disk to a…

Astrophysics of Galaxies · Physics 2023-08-04 Rimpei Chiba , Jennifer K. S. Friske , Ralph Schönrich

The distance to the Galactic center $R_0$ is a fundamental parameter for understanding the Milky Way, because all observations of our Galaxy are made from our heliocentric reference point. The uncertainty in $R_0$ limits our knowledge of…

Astrophysics of Galaxies · Physics 2022-12-14 Henry W. Leung , Jo Bovy , J. Ted Mackereth , Jason A. S. Hunt , Richard R. Lane , John C. Wilson
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