KINEMATICS OF THE X-SHAPED MILKY WAY BULGE: EXPECTATIONS FROM A SELF-CONSISTENT<i>N</i>-BODY MODEL

Qin, Yujing; Shen, Juntai; Li, Zhaoyu; Mao, Shude; Smith, M. C.; Rich, R. Michael; Kunder, Andrea; Liu, Chao

doi:10.1088/0004-637x/808/1/75

Cited by 24 publications

(27 citation statements)

References 52 publications

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“…The 'bulge bar' rows refer to the orbital speed at the end of the short thick bar (set at a radius of 2.1 kpc [8]) straddling the stellar bulge, while various published models [86,87] found it an angular velocity value (column 4), from which equation 6 here yielded its orbital speed at this radius (velocity in column 6), while equation 7 yielded an orbital period (column 8).…”

Section: Angular Rotation and Orbitsmentioning

confidence: 99%

A guided map to the spiral arms in the galactic disk of the Milky Way

Vallée

2017

Astronomical Review

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An up-to-date overview of the recent history is given, aiming is to present a helpful working guide to the literature and at the same time introduce key systems and observational results, starting from the Sun and going toward the Galactic Center and parts of the Zona Galactica Incognita, and beyond. We start by presenting an observational view of the Milky Way's disk plane (cartographic, dynamical, chemical crosscut, magnetic). This included the four long spiral arms in the disk of the Milky Way galaxy, their geometry, components, velocity, their widths and internal layers as well as onion-like ordered offsets, the central galactic bars, arm tangents, arm pitch and arm shape, arm origins near the Galactic Center, and other possible players in the spiral arm, such as the magnetic field and the dark matter content. After, we present a basic analysis of some theoretical predictions from galactic arm formation: numerical simulations or analytical theories, and observations are checked against predictions from various numerical simulations and analytical (theoretical) models.

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Section: Angular Rotation and Orbitsmentioning

confidence: 99%

A guided map to the spiral arms in the galactic disk of the Milky Way

Vallée

2017

Astronomical Review

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“…Shen et al (2010); Li & Shen (2012); Ness et al (2013b) showed that the observed X-shape and cylindrical rotation could be reproduced with an N-body B/P Bulge model. Gardner et al (2014); Qin et al (2015) explained the different kinematics of stars on the near and far parts of the X in the Bulge. Portail et al (2015b); Williams et al (2016); Abbott et al (2017) showed that the B/P Bulge is maintained by a wide range of orbits, both resonant and non-resonant.…”

Section: Bulge Dynamics and Massmentioning

confidence: 99%

Chemodynamical History of the Galactic Bulge

Barbuy

Chiappini

Gerhard

2018

Annu. Rev. Astron. Astrophys.

229

228

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The Galactic Bulge can uniquely be studied from large samples of individual stars, and is therefore of prime importance for understanding the stellar population structure of bulges in general. Here the observational evidence on the kinematics, chemical composition, and ages of Bulge stellar populations based on photometric and spectroscopic data is reviewed. The bulk of Bulge stars are old and span a metallicity range −1.5 < ∼ [Fe/H] < ∼ +0.5. Stellar populations and chemical properties suggest a star formation timescale below ∼2 Gyr. The overall Bulge is barred and follows cylindrical rotation, and the more metal-rich stars trace a Box/Peanut (B/P) structure. Dynamical models demonstrate the different spatial and orbital distributions of metal-rich and metalpoor stars. We discuss current Bulge formation scenarios based on dynamical, chemical, chemodynamical and cosmological models. Despite impressive progress we do not yet have a successful fully self-consistent chemodynamical Bulge model in the cosmological framework, and we will also need more extensive chrono-chemical-kinematic 3D map of stars to better constrain such models. arXiv:1805.01142v1 [astro-ph.GA] 3 May 2018 1 The bracket notation denotes logarithmic abundance ratios relative to Solar values, with [X/Y] = log(X/Y)star − log (X/Y)

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“…This is because a bar is preferentially supported by prograde orbits. As Qin et al (2015) showed, simply using the rotational velocity at a few spatial locations to estimate the pattern speed leads to biases. The geometric factors and averaging in the estimators are a necessary component.…”

Section: The Pattern Speed Of the Barmentioning

confidence: 99%

The pattern speed of the Milky Way bar from transverse velocities

Sanders

Smith

Evans

2019

Monthly Notices of the Royal Astronomical Society

135

102

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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 two of the three Galactic coordinates. We apply our method to the proper motion data from a combination of Gaia DR2 and VISTA Variables in the Via Lactea (VVV) to measure the pattern speed of the bar as Ω p = (41 ± 3) km s −1 kpc −1 (where the error is statistical). This puts the corotation radius at (5.7 ± 0.4) kpc, under the assumptions of the standard peculiar motion of the Sun and the absence of non-axisymmetric streaming in the Solar neighbourhood. The obtained result uses only data on the near-side of the bar which produces consistent measurements of the distance and velocity of the centre of the Galaxy. Addition of the data on the far-side of the bar pulls the pattern speed down to Ω p = (31 ± 1) km s −1 kpc −1 but requires a lower transverse velocity for the Galactic centre than observed. This suggests systematics of 5 − 10 km s −1 kpc −1 dominate the uncertainty. We demonstrate using a dynamically-formed bar/bulge simulation that even with the limited field of view of the VVV survey our method robustly recovers the pattern speed.

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KINEMATICS OF THE X-SHAPED MILKY WAY BULGE: EXPECTATIONS FROM A SELF-CONSISTENTN-BODY MODEL

Cited by 24 publications

References 52 publications

A guided map to the spiral arms in the galactic disk of the Milky Way

A guided map to the spiral arms in the galactic disk of the Milky Way

Chemodynamical History of the Galactic Bulge

The pattern speed of the Milky Way bar from transverse velocities

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