Vertical distribution of Galactic disk stars - I. Kinematics and metallicity

By C. Soubiran, O. Bienaym'e, A. D. Bordeaux, O. Strasbourg. 2002

200 citations recorded by the source corpus.

Nearly 400 Tycho-2 stars have been observed in a 720 square degree field in the direction of the North Galactic Pole with the high resolution echelle spectrograph ELODIE. Absolute magnitudes, effective temperatures, gravities and metallicities have been estimated, as well as distances and 3D velocities. Most of these stars are clump giants and span typical distances from 200 pc to 800 pc to the galactic mid-plane. This new sample. free of any kinematical and metallicity bias, is used to investigate the vertical distribution of disk stars. The old thin disk and thick disk populations are deconvolved from the velocity-metallicity distribution of the sample and their parameters are determined. The thick disk is found to have a moderate rotational lag of -51 ′5 km s - 1 with respect to the Sun with velocity ellipsoid (σ U , σ V , σ W ) = (63 ′ 6.39 ′ 4,39 ′ 4)km s - 1 , mean metallicity of [Fe/H] = -0.48 ′ 0.05 and a high local normalization of 15 ′ 7%. Combining this NGP sample with a local sample of giant stars from the Hipparcos catalogue, the orientation of the velocity ellipsoid is investigated as a function of distance to the plane and metallicity. We find no vertex deviation for old stars, consistent with an axisymmetric Galaxy. Paper II is devoted to the dynamical analysis of the sample, puting new constraints on the vertical force perpendicular to the galactic plane and on the total mass density in the galactic plane.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/6436884ce9bd3bd882bdf84d6ae1b2328cf27607

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Citations in the corpus

FORMATION AND EVOLUTION OF THE DISK SYSTEM OF THE MILKY WAY: [α/Fe] RATIOS AND KINEMATICS OF THE SEGUE G-DWARF SAMPLE (2011, methodology): “A small gradient of−5.6± 1.1 km s−1 kpc−1 is found for the thick-disk subsample, which lags theVLSR by∼40 km s−1, not far from the lag of 51 km s−1 obtained by Soubiran et al. (2003).”
THE VERTICAL METALLICITY GRADIENT OF THE MILKY WAY DISK: TRANSITIONS IN [α/Fe] POPULATIONS (2014, background): “When separated by kinematics (e.g., Soubiran et al. 2003), the thin disk is metal-rich (mean [Fe/H]≈ −0.2) and α-poor, while the thick disk is relatively metal-poor (mean [Fe/H]≈ −0.6) and enhanced in [α/Fe] (Gilmore & Wyse 1985; Wyse & Gilmore 1995; Chiba & Beers 2000; Fuhrmann 1998, 2011;…”
Vertical distribution of Galactic disk stars , IV. AMR and AVR from clump giants (2007, methodology): “This paper is the continuation of previous papers (Soubiran et al. 2003, hereafter Paper I and Siebert et al. 2003, hereafter Paper II) where we investigated the vertical distribution of disk stars with local and distant samples of clump giants.”
Evolutionary synthesis of galaxies at high spectral resolution with the code PEGASE-HR. Metallicity and age tracers (2004, methodology): “Otherwise they are estimated with the TGMET procedure, which consists in least square fits of the target spectrum to reference spectra with known atmospheric parameters (Katz et al. 1998; Soubiran et al. 2003).”
THE GENESIS OF THE MILKY WAY'S THICK DISK VIA STELLAR MIGRATION (2010, background): “Kinematically, thick disk stars have larger velocity dispersions and lag the net rotation of the disk (Nissen 1995; Chiba & Beers 2000; Gilmore et al. 2002; Soubiran et al. 2003; Parker et al. 2004; Wyse et al. 2006).”
Simulations of minor mergers - I. General properties of thick discs (2008, result): “In the case of the Milky Way, the observed σZ/σR at the position of the Sun is ∼ 0.6 (e.g., Chiba & Beers 2001; Vallenari et al. 2006), suggesting that the thick disk of the Galaxy could have been produced by a merger of intermediate inclination.”
Automatic determination of stellar atmospheric parameters and construction of stellar spectral templates of the Guoshoujing Telescope (LAMOST) (2011, methodology): “This work was later updated by Soubiran et al. (2000, 2003) to an internal accuracy of 86 K, 0.28 dex and 0.16 dex respectively forTeff , log g and [Fe/H] for F, G and K stars with SNR of 100, and accuracy of 102 K, 0.29 dex and 0.17 dex at SNR = 10.”
Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program - Galactic stellar populations and planets (2012, methodology): “Here, we adopted the mean values (asymmetric drift) and dispersion in the Gaussian distribution (characteristic velocity dispersion), and the population fractions were taken from B03 and Robin et al. (2003) (hereafter R03) (see also Ojha et al. 1996; Soubiran et al. 2003).”
A synthetic view on structure and evolution of the Milky Way (2003, background): “These values are in close agreement with a recent determination by Soubiran et al. (2003) who find a rotational lag of 51 km s−1, and a velocity ellipsoid (63± 6, 39± 4, 39± 4) km s−1.”
XHIP: An extended hipparcos compilation (2011, background): “…et al. (2011), Masseron et al. (2010), Gebran et al. (2010), Schuster (2010), Ramirez et al. (2009), Guillout et al. (2009), Nissen & Jenkins et al. (2008), Soubiran et al. (2008), Robinson et al. (2007), GCS3, Taylor (2005), Soubiran et al. (2003), Beers et al. (2000), and Chiba & Yoshi (1998).”
Chemodynamical evolution of the Milky Way disk - I. The solar vicinity (2012, background): “The metallicity peak of this oldest population is around−0.5, with a range of values that agree well with the results by Soubiran et al. (2003) for their thick-disk selection of clump giants.”
Coudé-feed stellar spectral library – atmospheric parameters (2010, methodology): “The program TGMET, developed by Katz et al. (1998) and improved by Soubiran et al. (2000, 2003), illustrates this approach.”
OXYGEN ABUNDANCES IN NEARBY FGK STARS AND THE GALACTIC CHEMICAL EVOLUTION OF THE LOCAL DISK AND HALO (2013, background): “…are assumed to have a Gaussian distribution in their Galactic space velocities, with mean U, V,W values and velocity dispersions (σ) adopted from Soubiran et al. (2003) for the thin and thick disks, and from Chiba & Beers (2000) for the halo.7 The probability that a star with Galactic space…”
THE SPATIAL STRUCTURE OF MONO-ABUNDANCE SUB-POPULATIONS OF THE MILKY WAY DISK (2011, background): “Generally, thick-disk components are found to be old (Bensby et al. 2005; Yoachim & Dalcanton 2008), kinematically hot (Chiba & Beers 2000; Soubiran et al. 2003; Gilmore et al. 2002; Yoachim & Dalcanton 2005), and metal-poor (compared to the thin-disk components), as well as enhanced in α-elements…”
The Galaxy in Context: Structural, Kinematic, and Integrated Properties (2016, background): “…an effect that is easily seen in sufficiently high-resolution (R 20,000) spectroscopic data (Fuhrmann 1998; Gratton et al. 2000; Prochaska et al. 2000; Reddy et al. 2003, 2006; Soubiran et al. 2003) and even possibly at [Fe/H] 0 (Hayden et al. 2015, Haywood et al. 2015, Kordopatis et al. 2015).”
Structural Parameters of Thin and Thick Disks in Edge-on Disk Galaxies (2005, background): “Kinematically, MW thick disk stars have both larger velocity dispersions and slower net rotation than stars in the thin disk (Nissen 1995; Chiba & Beers 2000; Gilmore et al. 2002; Soubiran et al. 2003; Parker et al. 2004).”