Velocity Shear of the Thick Disk from SPM3 Proper Motions at the South Galactic Pole

Simple item page
dc.creatorGirard, T. M.
dc.creatorKorchagin, V. I.
dc.creatorCasetti-Dinescu, D. I.
dc.creatorvan Altena, W. F.
dc.creatorLopez, C. E.
dc.creatorMonet, D. G.
dc.date2006-07-18
dc.date.accessioned2026-07-07T11:25:48Z
dc.date.available2026-07-07T11:25:48Z
dc.descriptionThe kinematical properties of the Galactic Thick Disk are studied using absolute proper motions from the SPM3 Catalog and 2MASS near-infrared photometry for a sample of ~1200 red giants in the direction of the South Galactic Pole. The photometrically-selected sample is dominated by Thick Disk stars, as indicated by the number-density distribution that varies with distance from the Galactic plane as a single-valued exponential over the range 1<z<4 kpc. The inferred scale height of the Thick Disk is 0.783 +/- 0.048 kpc. The kinematics of the sample are also consistent with disk-like motion. The U-velocity component is roughly constant, reflecting the Sun's peculiar motion, while a considerable shear is seen in the mean rotational velocity, V. The V-velocity profile's dependence on z is linear, with a gradient of dV/dz = -30 +/- 3 km/s/kpc. The velocity dispersions, in both U and V, show a lesser gradient of about 9 +/- 3 km/s/kpc. We demonstrate that the derived velocity and velocity-dispersion profiles are consistent with the assumptions of dynamical equilibrium and reasonable models of the overall Galactic potential.
dc.description38 pages, 9 figures, accepted for publication in AJ
dc.identifierhttps://arxiv.org/abs/astro-ph/0607417
dc.identifierhttp://arxiv.org/abs/astro-ph/0607417
dc.identifierAstron.J.132:1768-1782,2006
dc.identifierdoi:10.1086/507331
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/195622
dc.subjectAstrophysics
dc.titleVelocity Shear of the Thick Disk from SPM3 Proper Motions at the South Galactic Pole
dc.typetext

Files

Collections

arXiv