Outer Galactic disk A and F stars space motions

DOI

A and F stars can be used as probes of outer Galactic disk kinematics: here we extend the work of Harris et al. (2018, Cat. J/MNRAS/475/1680) by crossmatching their A/F sample with Gaia DR2 to bring in proper motions. These are combined with the already measured radial velocities and spectro-photometric distances to obtain full space motions. We use this sample of 1173 stars, located in two pencil-beam sightlines (l=178{deg} and l=118{deg}), to sample the Galactocentric velocity field out to almost R_G_=15kpc. We find there are significant differences in all three (radial, azimuthal and vertical) kinematic components between the two directions. The rotation curve is roughly flat in the anticentre direction, confirming and extending the result of Kawata et al. (2018MNRAS.479L.108K) thanks to the greater reach of our spectro-photometric distance scale. However at l=118{deg} the circular velocity rises outwards from R_G_=10.5kpc and there is a more pronounced gradient in radial motion than is seen at l=178{deg}. Furthermore, the A star radial motion differs from the F stars by ~10km/s. We discuss our findings in the context of perturbers potentially responsible for the trends, such as the central bar, spiral arms, the warp and external satellites. Our results at l=178{deg} are broadly consistent with previous work on K giants in the anticentre, but the kinematics at l=118{deg} in the Perseus region do not yet reconcile easily with bar or spiral arm perturbation.

Cone search capability for table J/MNRAS/485/2312/table (Table of data)

Identifier
DOI http://doi.org/10.26093/cds/vizier.74852312
Source https://dc.g-vo.org/rr/q/lp/custom/CDS.VizieR/J/MNRAS/485/2312
Related Identifier https://cdsarc.cds.unistra.fr/viz-bin/cat/J/MNRAS/485/2312
Related Identifier http://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/MNRAS/485/2312
Metadata Access http://dc.g-vo.org/rr/q/pmh/pubreg.xml?verb=GetRecord&metadataPrefix=oai_b2find&identifier=ivo://CDS.VizieR/J/MNRAS/485/2312
Provenance
Creator Harris A.; Drew J.E.; Monguio M.
Publisher CDS
Publication Year 2019
Rights https://cds.unistra.fr/vizier-org/licences_vizier.html
OpenAccess true
Contact CDS support team <cds-question(at)unistra.fr>
Representation
Resource Type Dataset; AstroObjects
Discipline Astrophysics and Astronomy; Exoplanet Astronomy; Galactic and extragalactic Astronomy; Natural Sciences; Observational Astronomy; Physics; Stellar Astronomy