The Kinematics of Late-Type Stars in the Solar Cylinder Studied With SDSS Data

Fuchs, B.; Dettbarn, C.; Rix, Hans-Walter; Bizyaev, Dmitry; Brewington, H.; Jahreiß, H.; Klement, Rainer J.; Malanushenko, Viktor; Oravetz, D.; Pan, Kaike; Simmons, Audrey; Snedden, Stephanie A.

doi:10.1088/0004-6256/137/5/4149

Cited by 67 publications

(86 citation statements)

References 48 publications

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“…The non-vanishing tilt was also found by and Fuchs et al (2009). The general kinematic features of the thick disc are also in agreement with the results obtained by Carollo et al (2010), Pasetto et al (2012a), andMoni Bidin et al (2012), although the latter find a non-null vertex deviation of thick disc stars, which increases with the distance to the GC.…”

Section: Thick Discsupporting

confidence: 89%

Conditions of consistency for multicomponent axisymmetric stellar systems

Cubarsi

2014

A&A

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Solving the Boltzmann collisionless equation under the axisymmetric hypothesis introduces serious limitations on describing the kinematics of a single stellar system according to the local Galactic observables. Instead of relaxing the hypothesis of axisymmetry, one alternative is to assume a mixture model. For a finite mixture of ellipsoidal velocity distributions, the coexistence of several stellar populations sharing a common potential introduces a set of conditions of consistency that may also constrain the population kinematics. For only a few potentials, the populations may have independent mean velocities and unconstrained velocity ellipsoids. In this paper, we determine which axisymmetric potentials are connected with a more flexible superposition of the stellar populations. The conditions of consistency are checked against recent results derived from kinematic surveys of the solar neighbourhood that include RAdial Velocity Experiment (RAVE) data. Several key observables are used to determine whether the axisymmetric mixture model is able to account for the main features of the local velocity distribution, such as the vertex deviation associated with the second central moment μ θ , the population radial mean velocities, the radial gradient of the moment μ z , the tilt of the velocity ellipsoids, and the existence of stars with no net rotation. In addition, the mixture moments for an arbitrary number of populations are derived in terms of the one-to-one mean velocity differences in order to study whether a more populated mixture could add any new features to the velocity distribution that remain unnoticed in a two-component mixture. According to this analysis, the quasi-stationary potential is the only potential allowing arbitrary directions of the population mean velocities. Then, the apparent vertex deviation of the total velocity distribution is due to the difference of the mean velocities of the populations whose velocity ellipsoids have no vertex deviation. For a non-separable potential, the population velocity ellipsoids have the same orientation and point towards the Galactic centre. For a potential separable in addition in cylindrical coordinates, the population velocity ellipsoids may have arbitrary tilt.

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Section: Thick Discsupporting

confidence: 89%

Conditions of consistency for multicomponent axisymmetric stellar systems

Cubarsi

2014

A&A

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“…Yanny et al 2003;Belokurov et al 2006) and new Milky Way companions (e.g., Willman et al 2005;Belokurov et al 2007), as well as unprecedented in situ mapping of the stellar density (Jurić et al 2008) and metallicity ) distributions of the Milky Way and confirmation of the dual-halo structure of the Milky Way (Carollo et al 2007). SDSS has proven to be a valuable resource for statistical investigations of the properties of low-mass stars, including their magnetic activity and chromospheric properties (West et al 2004, flare characteristics (Kowalski et al 2009) and their use as tracers of Galactic structure and kinematics (Bochanski et al 2007a;Fuchs et al 2009). …”

Section: Introductionmentioning

confidence: 99%

The Luminosity and Mass Functions of Low-Mass Stars in the Galactic Disk. Ii. The Field

Bochanski¹,

Hawley²,

Covey³

et al. 2010

The Astronomical Journal

322

305

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We report on new measurements of the luminosity function (LF) and mass function (MF) of field low-mass dwarfs derived from Sloan Digital Sky Survey (SDSS) Data Release 6 (DR6) photometry. The analysis incorporates ∼ 15 million low-mass stars (0.1 M ⊙ < M < 0.8M ⊙ ), spread over 8,400 square degrees. Stellar distances are estimated using new photometric parallax relations, constructed from ugriz photometry of nearby low-mass stars with trigonometric parallaxes. We use a technique that simultaneously measures Galactic structure and the stellar LF from 7 < M r < 16. We compare the LF to previous studies and convert to a MF using the mass-luminosity relations of Delfosse et al. (2000). The system MF, measured over −1.0 < log M/M ⊙ < −0.1, is well-described by a log-normal distribution with M • = 0.25 M ⊙ . We stress that our results should not be extrapolated to other mass regimes. Our work generally agrees with prior low-mass stellar MFs and places strong constraints in future star-formation studies of the Milky Way.

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“…Munn et al (2017) corrected the disk luminosity function for missing objects with V 40 tan < or 120 > km s −1 using the modified maximum survey volume of Lam et al (2015) as the density estimator. However, they treated the disk objects as a single population, and summed the thin and thick disk profiles of Jurić et al (2008) as a single disk density profile and used the Fuchs et al (2009) results to model the kinematics of the disk. Hence, they corrected for the overall number of disk objects in their survey, but these corrections do not include the change in the relative numbers of thin and thick disk objects due to the V 40 120 tan = -km s −1 cut.…”

Section: Thin Disk and Thick Disk Agesmentioning

confidence: 99%

The Ages of the Thin Disk, Thick Disk, and the Halo from Nearby White Dwarfs

Kilic

Munn

Harris

et al. 2017

ApJ

145

127

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We present a detailed analysis of the white dwarf luminosity functions derived from the local 40 pc sample and the deep proper motion catalog of Munn et al. Many previous studies have ignored the contribution of thick disk white dwarfs to the Galactic disk luminosity function, which results in an erroneous age measurement. We demonstrate that the ratio of thick/thin disk white dwarfs is roughly 20% in the local sample. Simultaneously fitting for both disk components, we derive ages of 6.8-7.0 Gyr for the thin disk and 8.7±0.1 Gyr for the thick disk from the local 40 pc sample. Similarly, we derive ages of 7.4-8.2 Gyr for the thin disk and 9.5-9.9 Gyr for the thick disk from the deep proper motion catalog, which shows no evidence of a deviation from a constant star formation rate in the past 2.5 Gyr. We constrain the time difference between the onset of star formation in the thin disk and the thick disk to be 1.6 0.4Gyr. The faint end of the luminosity function for the halo white dwarfs is less constrained, resulting in an age estimate of 12.5 3.4 -+Gyr for the Galactic inner halo. This is the first time that ages for all three major components of the Galaxy have been obtained from a sample of field white dwarfs that is large enough to contain significant numbers of disk and halo objects. The resultant ages agree reasonably well with the age estimates for the oldest open and globular clusters.

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The Kinematics of Late-Type Stars in the Solar Cylinder Studied With SDSS Data

Cited by 67 publications

References 48 publications

Conditions of consistency for multicomponent axisymmetric stellar systems

Conditions of consistency for multicomponent axisymmetric stellar systems

The Luminosity and Mass Functions of Low-Mass Stars in the Galactic Disk. Ii. The Field

The Ages of the Thin Disk, Thick Disk, and the Halo from Nearby White Dwarfs

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