TY - JOUR
T1 - The wobbly Galaxy : kinematics north and south with RAVE red-clump giants
AU - Williams, M. E. K.
AU - Steinmetz, M.
AU - Binney, J.
AU - Siebert, A.
AU - Enke, H.
AU - Famaey, B.
AU - Minchev, I.
AU - Jong, R. S. de
AU - Boeche, C.
AU - Freeman, K. C.
AU - Bienayme, O.
AU - Bland-Hawthorn, J.
AU - Gibson, B. K.
AU - Gilmore, G. F.
AU - Grebel, E. K.
AU - Helmi, A.
AU - Kordopatis, G.
AU - Munari, U.
AU - Navarro, J. F.
AU - Reid, W.
PY - 2013
Y1 - 2013
N2 - TheRAdialVelocity Experiment survey, combined with proper motions and distance estimates, can be used to study in detail stellar kinematics in the extended solar neighbourhood (solar suburb). Using 72 365 red-clump stars, we examine the mean velocity components in 3D between 6 < R < 10 kpc and -2 < Z < 2 kpc, concentrating on north-south differences. Simple parametric fits to the (R, Z) trends for Vφ and the velocity dispersions are presented. We confirm the recently discovered gradient in mean Galactocentric radial velocity, VR, finding that the gradient is marked below the plane (δ(VR)/δR=-8 kms-1 kpc-1 for Z <0, vanishing to zero above the plane), with a Z gradient thus also present. The vertical velocity, VZ, also shows clear, large-amplitude (|VZ| = 17 km s-1) structure, with indications of a rarefaction- compression pattern, suggestive of wave-like behaviour. We perform a rigorous error analysis, tracing sources of both systematic and random errors. We confirm the north-south differences in VR and VZ along the line of sight, with the VR estimated independent of the proper motions. The complex three-dimensional structure of velocity space presents challenges for future modelling of the Galactic disc, with the Galactic bar, spiral arms and excitation of wave-like structures all probably playing a role.
AB - TheRAdialVelocity Experiment survey, combined with proper motions and distance estimates, can be used to study in detail stellar kinematics in the extended solar neighbourhood (solar suburb). Using 72 365 red-clump stars, we examine the mean velocity components in 3D between 6 < R < 10 kpc and -2 < Z < 2 kpc, concentrating on north-south differences. Simple parametric fits to the (R, Z) trends for Vφ and the velocity dispersions are presented. We confirm the recently discovered gradient in mean Galactocentric radial velocity, VR, finding that the gradient is marked below the plane (δ(VR)/δR=-8 kms-1 kpc-1 for Z <0, vanishing to zero above the plane), with a Z gradient thus also present. The vertical velocity, VZ, also shows clear, large-amplitude (|VZ| = 17 km s-1) structure, with indications of a rarefaction- compression pattern, suggestive of wave-like behaviour. We perform a rigorous error analysis, tracing sources of both systematic and random errors. We confirm the north-south differences in VR and VZ along the line of sight, with the VR estimated independent of the proper motions. The complex three-dimensional structure of velocity space presents challenges for future modelling of the Galactic disc, with the Galactic bar, spiral arms and excitation of wave-like structures all probably playing a role.
KW - galaxies
KW - kinematics
KW - stars
UR - http://handle.uws.edu.au:8081/1959.7/uws:31211
U2 - 10.1093/mnras/stt1522
DO - 10.1093/mnras/stt1522
M3 - Article
SN - 0035-8711
VL - 436
SP - 101
EP - 121
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -