THE MILKY WAY TOMOGRAPHY WITH SDSS. III. STELLAR KINEMATICS

By Željko Ivezic´, B. Sesar, Mario Juric, J. Munn, A. Kowalski, Sarah Loebman, Nicholas A. Bond, Rok Roskar, Timothy C. Beers, J. J. Dalcanton and 47 more. 2009

177 citations recorded by the source corpus.

We study Milky Way kinematics using a sample of 18.8 million main-sequence stars with r < 20 and proper-motion measurements derived from Sloan Digital Sky Survey (SDSS) and POSS astrometry, including ∼170,000 stars with radial-velocity measurements from the SDSS spectroscopic survey. Distances to stars are determined using a photometric-parallax relation, covering a distance range from ∼100 pc to 10 kpc over a quarter of the sky at high Galactic latitudes (|b|>20°). We find that in the region defined by 1 kpc <Z< 5 kpc and 3 kpc <R< 13 kpc, the rotational velocity for disk stars smoothly decreases, and all three components of the velocity dispersion increase, with distance from the Galactic plane. In contrast, the velocity ellipsoid for halo stars is aligned with a spherical coordinate system and appears to be spatially invariant within the probed volume. The velocity distribution of nearby (Z < 1 kpc) K/M stars is complex, and cannot be described by a standard Schwarzschild ellipsoid. For stars in a distance-limited subsample of stars (<100 pc), we detect a multi-modal velocity distribution consistent with that seen by HIPPARCOS. This strong non-Gaussianity significantly affects the measurements of the velocity-ellipsoid tilt and vertex deviation when using the Schwarzschild approximation. We develop and test a simple descriptive model for the overall kinematic behavior that captures these features over most of the probed volume, and can be used to search for substructure in kinematic and metallicity space. We use this model to predict further improvements in kinematic mapping of the Galaxy expected from Gaia and the Large Synoptic Survey Telescope.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/b1aaf226eb8e9f464911fb59a8c54ea49833d83a

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Citations in the corpus

THE GENESIS OF THE MILKY WAY'S THICK DISK VIA STELLAR MIGRATION (2010, result): “The properties of the Roškar et al. model for the overall spatial, metallicity and kinematic distributions of the Milky Way stars are in qualitative agreement with the SDSS data (Jurić et al. 2008; Ivezić et al. 2008; Bond et al. 2010).”
Evidence for an Intermediate-mass Milky Way from Gaia DR2 Halo Globular Cluster Motions (2018, result): “…et al. (2016), both of which favour an isotopic or even tangentially-anisotropic halo (although the uncertainties in the latter were large enough that that results cannot be called truly discrepant), but in good agreement with the radial estimates from Bond et al. (2010) and Deason et al. (2012).”
THE CASE FOR THE DUAL HALO OF THE MILKY WAY (2011, methodology): “These proper motion errors were determined using a sample of ∼60,000 quasars and are robust (see Section 2.3 of Bond et al. 2010).”
Automatic determination of stellar atmospheric parameters and construction of stellar spectral templates of the Guoshoujing Telescope (LAMOST) (2011, methodology): “They will be used to match the structure and evolution of the Milky Way to the current generation of galaxy formation models (Wyse 2006; Jurić et al. 2008; Ivezíc et al. 2008; Bond et al. 2010; Jofré et al. 2011).”
Co-formation of the disc and the stellar halo (2018, methodology): “Combining the SDSS observations with the digitized photographic plate measurements, Bond et al. (2010) increased the stellar halo sample further and derived β = 0.67.”
THE METALLICITY DISTRIBUTION FUNCTIONS OF SEGUE G AND K DWARFS: CONSTRAINTS FOR DISK CHEMICAL EVOLUTION AND FORMATION (2011, methodology): “They also detect a clear break between the disk and halo stars, which have a mean metallicity of around −1.4 (Bond et al. 2010).”
GALACTOSEISMOLOGY: DISCOVERY OF VERTICAL WAVES IN THE GALACTIC DISK (2012, methodology): “Bond et al. (2010) analyzed SDSS-DR7 data and reported a difference of ∼8 km s−1 between the bulk motions North and South of the midplane; they attributed this difference to a systematic radial velocity error for M dwarfs possibly due to the limited set of velocity template spectra used in the SDSS…”
Constraining the Galaxy's dark halo with RAVE stars (2014, background): “We denote the velocity component along the long axis of the velocity ellipsoid – pointing more or less towards the GC – with V1, the azimuthal component with Vφ , and the remaining component with V3 which is close to the latitudinal direction (cf. also Bond et al. 2010).”
The Wobbly Galaxy : kinematics north and south with RAVE red-clump giants (2013, unknown): “The form is not dissimilar to that given for high-metallicity stars in Ivezić et al. (2008) between 2 < R < 16 kpc and 0 < |Z| < 9 kpc (〈VY〉 = 20.1 + 19.2|Z kpc−1|1.25 km s−1) and Bond et al. (2010) between 0 < R < 20 kpc and 0 < |Z| < 10 kpc (〈Vφ〉 = −205 + 19.2|Z/kpc|1.25 km s−1).”
Dissecting simulated disc galaxies - I. The structure of mono-age populations (2014, background): “Its stars have a higher velocity dispersion, and lag behind in rotation compared to the thin disc (Soubiran, Bienaymé, & Siebert 2003; Allende Prieto et al. 2006; Bond et al. 2010).”
FORMATION AND EVOLUTION OF THE DISK SYSTEM OF THE MILKY WAY: [α/Fe] RATIOS AND KINEMATICS OF THE SEGUE G-DWARF SAMPLE (2011, methodology): “Then, by adopting the improved expression by Bond et al. (2010), we estimate the photometric metallicities for our sample.”
KINEMATICS OF THE STELLAR HALO AND THE MASS DISTRIBUTION OF THE MILKY WAY USING BLUE HORIZONTAL BRANCH STARS (2012, background): “D11 claims for the tangential inner halo are in contrast with the result by Bond et al. (2010) who found the inner halo to be radial in the similar region (d ≈ 10 kpc).”
LSST: From Science Drivers to Reference Design and Anticipated Data Products (2008, methodology): “The adopted metallicity for each star is based on a model from Ivezić et al. (2008a), and proper motions are based on the kinematic model of Bond et al. (2010).”
THE NINTH DATA RELEASE OF THE SLOAN DIGITAL SKY SURVEY: FIRST SPECTROSCOPIC DATA FROM THE SDSS-III BARYON OSCILLATION SPECTROSCOPIC SURVEY (2012, background): “This offset is further described by Bond et al. (2010) in the context of the DR7 proper motions, and could be due to small differential refraction correction issues in USNO-B for these very blue objects (and is therefore likely not relevant to the proper motions of typical stars).”