AffiliationUniv Arizona, Steward Observ
Keywordsstars: kinematics and dynamics
Galaxy: kinematics and dynamics
MetadataShow full item record
PublisherOXFORD UNIV PRESS
CitationJ A Sellwood, Wilma H Trick, R G Carlberg, Johanna Coronado, Hans-Walter Rix, Discriminating among theories of spiral structure using Gaia DR2, Monthly Notices of the Royal Astronomical Society, Volume 484, Issue 3, April 2019, Pages 3154–3167, https://doi.org/10.1093/mnras/stz140
Rights© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
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AbstractWe compare the distribution in position and velocity of nearby stars from the Gaia DR2 radial velocity sample with predictions of current theories for spirals in disc galaxies. Although the rich substructure in velocity space contains the same information, we find it more revealing to reproject the data into action-angle variables, and we describe why resonant scattering would be more readily identifiable in these variables. We compute the predicted changes to the phase-space density, in multiple different projections, that would be caused by a simplified isolated spiral pattern, finding widely differing predictions from each theory. We conclude that the phase-space structure present in the Gaia data shares many of the qualitative features expected in the transient spiral mode model. We argue that the popular picture of apparently swing-amplified spirals results from the superposition of a few underlying spiral modes.
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