Signatures of bulge triaxiality from kinematics in Baade's window

  title={Signatures of bulge triaxiality from kinematics in Baade's window},
  author={HongSheng Zhao and D.N.Spergel and R.M.Rich},
  journal={The Astronomical Journal},
We study a sample of 62 Baade's Window, (l,b) = (1, -4)deg, K giants that have published proper motions, radial velocity, and metallicity. Using R(sub 0) = 8 kpc, we construct the velocity ellipsoids, namely the 3x3 velocity dispersion tensors, for the metal rich stars ((Fe/H) greater than or equal to 0) and metal poor stars ((Fe/H) less than or equal to -0.2). After diagonalizing the tensor, we find a vertex deviation characteristic of a nonaxisymmetric system. Eigenvalues for the two velocity… 

Evidence of a Metal-rich Galactic Bar from the Vertex Deviation of the Velocity Ellipsoid

We combine radial velocities, proper motions, and low-resolution abundances for a sample of 315 K and M giants in the Baade's window (l, b) = (0.9°, -4°) Galactic bulge field. The velocity ellipsoid

Kinematics, Metallicities, and Stellar Distributions in the Inner Disk and Bulge of the Milky Way

We present the results of a photometric and spectroscopic study of stars in four fields toward the inner disk and Galactic bulge. The fields are located symmetrically about the minor axis of the

Mapping the tilt of the Milky Way bulge velocity ellipsoids with ARGOS and Gaia DR2

Until the recent advent of Gaia Data Release 2 (DR2) and deep multi-object spectroscopy, it has been difficult to obtain 6D phase space information for large numbers of stars beyond 4 kpc, in

Mapping stellar kinematics across the Galactic bar: HST measurements of proper motions in 35 fields

We present a proper motion mini-survey of 35 fields in the vicinity of Baade window, (l, b) = (1 degrees, -4 degrees), sampling roughly a 5 x 2.5-deg(2) region of the Galactic bar. Our second epoch

Abundances of Baade’s Window Giants from Keck HIRES Spectra. II. The Alpha and Light Odd Elements

We report detailed abundances of O, Na, Mg, Al, Si, Ca, and Ti—elements produced by massive stars—for 27 red giants toward the Galactic bulge in Baade's window. These species are overabundant in the

The metallicity distribution of bulge clump giants in Baade’s window

Aims. We seek to constrain the formation of the Galactic bulge by analysing the detailed chemical composition of a large sample of red clump stars in Baade’s window. These stars were selected to

A new model for the Milky Way bar

Abstract We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using χ2 minimisation, we find that the best-fit Galactic bar model has a

Detailed Analysis of Nearby Bulgelike Dwarf Stars. III. α-Element and Heavy-Element Abundances

The present sample of nearby bulgelike dwarf stars has kinematics and metallicities characteristic of a probable inner disk or bulge origin. Ages derived by using isochrones give 10-11 Gyr for these

The COMBS Survey - II. Distinguishing the metal-poor bulge from the halo interlopers

Abstract The metal-poor stars in the bulge are important relics of the Milky Way’s formation history, as simulations predict that they are some of the oldest stars in the Galaxy. In order to

The Milky Way bar/bulge in proper motions: a 3D view from VIRAC and Gaia

We have derived absolute proper motions of the entire Galactic bulge region from VVV Infrared Astrometric Catalogue (VIRAC) and Gaia. We present these both as integrated on-sky maps and, after