Facial reconstruction

Search LJMU Research Online

Browse Repository | Browse E-Theses

The effects of bar-spiral coupling on stellar kinematics in the Galaxy

Monari, G, Famaey, B, Siebert, A, Grand, RJJ, Kawata, D and Boily, C (2016) The effects of bar-spiral coupling on stellar kinematics in the Galaxy. Monthly Notices of the Royal Astronomical Society, 461 (4). pp. 3835-3846. ISSN 0035-8711

stw1564.pdf - Published Version

Download (3MB) | Preview


We investigate models of the Milky Way disc taking into account simultaneously the bar anda two-armed quasi-static spiral pattern. Away from major resonance overlaps, the mean stellarradial motions in the plane are essentially a linear superposition of the isolated effects ofthe bar and spirals. Thus, provided the bar is strong enough, even in the presence of spiralarms, these mean radial motions are predominantly affected by the Galactic bar for large-scalevelocity fluctuations. This is evident when comparing the peculiar line-of-sight velocity powerspectrum of our coupled models with bar-only models. However, we show how forthcomingspectroscopic surveys could disentangle bar-only non-axisymmetric models of the Galaxyfrom models in which spiral arms have a significant amplitude.We also point out that overlapsof low-order resonances are sufficient to enhance stellar churning within the disc, even whenthe spirals amplitude is kept constant. Nevertheless, for churning to be truly non-local, strongeror (more likely) transient amplitudes would be needed: otherwise the disc is actually mostlyunaffected by churning in the present models. Finally, regarding vertical breathing modes, thecombined effect of the bar and spirals on vertical motions is a clear non-linear superpositionof the isolated effects of both components, significantly superseding the linear superpositionof modes produced by each perturber separately, thereby providing an additional effect toconsider when analysing the observed breathing mode of the Galactic disc in the extendedsolar neighbourhood.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: 0201 Astronomical and Space Sciences; Astronomy & Astrophysics
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press (OUP)
SWORD Depositor: A Symplectic
Date Deposited: 19 Apr 2023 11:02
Last Modified: 19 Apr 2023 11:02
DOI or ID number: 10.1093/mnras/stw1564
URI: https://researchonline.ljmu.ac.uk/id/eprint/19349
View Item View Item