The Gravitational Potential Near the Sun From Segue K-Dwarf Kinematics

Zhang, Lan; Rix, Hans─Walter; Ven, Glenn van de; Bovy, Jo; Liu, Chao; Zhao, Gang

doi:10.1088/0004-637x/772/2/108

Cited by 152 publications

(239 citation statements)

References 45 publications

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“…The values of the local dark matter density derived in case of model A and B are 0.01051 and 0.01085 M pc −3 , respectively. They are only slightly higher than 0.008 ± 0.003 M pc −3 proposed by Bovy & Tremaine (2012) and 0.0075 ± 0.0021 M pc −3 , which is recently obtained by Zhang et al (2013) using SDSS/SEGUE data. Our values are at less than 2σ from the values derived by these authors.…”

Section: The Dynamical Mass and The Age-velocity Relationcontrasting

confidence: 43%

The Besançon Galaxy model renewed

Czekaj

Robin

Figueras

et al. 2014

A&A

133

219

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Context. The understanding of Galaxy evolution can be facilitated by the use of population synthesis models, which allows us to test hypotheses on the star formation history, star evolution, and chemical and dynamical evolution of the Galaxy. Aims. The new version of the Besançon Galaxy model (BGM) aims to provide a more flexible and powerful tool to investigate the initial mass function (IMF) and star formation rate (SFR) of the Galactic disc. Methods. We present a new strategy for the generation of thin disc stars, which assumes the IMF, SFR and evolutionary tracks as free parameters. We have updated most of the ingredients for the star count production and, for the first time, binary stars are generated in a consistent way. The local dynamical self-consistency is maintained in this new scheme. We then compare simulations from the new model with Tycho-2 data and the local luminosity function, as a first test to verify and constrain the new ingredients. The effects of changing thirteen different ingredients of the model are systematically studied. Results. For the first time, a full sky comparison is performed between BGM and data. This strategy allows us to constrain the IMF slope at high masses, which is found to be close to 3.0 and excludes a shallower slope such as Salpeter's one. The SFR is found decreasing whatever IMF is assumed. The model is compatible with a local dark matter density of 0.011 M pc −3 implying that there is no compelling evidence for the significant amount of dark matter in the disc. While the model is fitted to Tycho-2 data, which is a magnitude limited sample with V < 11, we check that it is still consistent with fainter stars. Conclusions. The new model constitutes a new basis for further comparisons with large scale surveys and is being prepared to become a powerful tool for the analysis of the Gaia mission data.

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Section: The Dynamical Mass and The Age-velocity Relationcontrasting

confidence: 43%

The Besançon Galaxy model renewed

Czekaj

Robin

Figueras

et al. 2014

A&A

133

219

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“…Salucci et al 2010, Catena & Ullio 2010and McMillan 2011 as well as local determinations (e.g. Bovy & Tremaine 2012;Zhang et al 2013;, pointing to a nearly spherical local Milky Way dark matter halo (Read 2014).…”

Section: Dark Matter Halomentioning

confidence: 85%

The Milky Way's rotation curve out to 100 kpc and its constraint on the Galactic mass distribution

Huang

Liu

Yuan

et al. 2016

Mon. Not. R. Astron. Soc.

165

179

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The rotation curve (RC) of the Milky Way out to ∼ 100 kpc has been constructed using ∼ 16, 000 primary red clump giants (PRCGs) in the outer disk selected from the LSS-GAC and the SDSS-III/APOGEE survey, combined with ∼ 5700 halo K giants (HKGs) selected from the SDSS/SEGUE survey. To derive the RC, the PRCG sample of the warm disc population and the HKG sample of halo stellar population are respectively analyzed using a kinematical model allowing for the asymmetric drift corrections and re-analyzed using the spherical Jeans equation along with measurements of the anisotropic parameter β currently available. The typical uncertainties of RC derived from the PRCG and HKG samples are respectively 5-7 km s −1 and several tens km s −1 . We determine a circular velocity at the solar position, V c (R 0 ) = 240 ± 6 km s −1 and an azimuthal peculiar speed of the Sun, V ⊙ = 12.1 ± 7.6 km s −1 , both in good agreement with the previous determinations. The newly constructed RC has a generally flat value of 240 km s −1 within a Galactocentric distance r of 25 kpc and then decreases steadily to 150 km s −1 at r ∼ 100 kpc. On top of this overall trend, the RC exhibits two prominent localized dips, one at r ∼ 11 kpc and another at r ∼ 19 kpc. From the newly constructed RC, combined with other constraints, we have built a parametrized mass model for the Galaxy, yielding a virial mass of the Milky Way's dark matter halo of 0.90 +0.07 −0.08 × 10 12 M ⊙ and a local dark matter density, ρ ⊙,dm = 0.32 +0.02 −0.02 GeV cm −3 .

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“…Bond et al 2010), Σ total, MW = 70 M pc −2 (e.g. Zhang et al 2013), and a thin disk height, H MW = 350 pc (e.g. Jurić et al 2008).…”

Section: Equal Velocity Dispersions Of Gas and Starsmentioning

confidence: 99%

On the cosmic evolution of the specific star formation rate

Lehnert

Driel

Tiran

et al. 2015

A&A

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The apparent correlation between the specific star formation rate (sSFR) and total stellar mass (M ) of galaxies is a fundamental relationship indicating how they formed their stellar populations. To attempt to understand this relation, we hypothesize that the relation and its evolution is regulated by the increase in the stellar and gas mass surface density in galaxies with redshift, which is itself governed by the angular momentum of the accreted gas, the amount of available gas, and by self-regulation of star formation. With our model, we can reproduce the specific SFR− M relations at z ∼ 1-2 by assuming gas fractions and gas mass surface densities similar to those observed for z = 1-2 galaxies. We further argue that it is the increasing angular momentum with cosmic time that causes a decrease in the surface density of accreted gas. The gas mass surface densities in galaxies are controlled by the centrifugal support (i.e., angular momentum), and the sSFR is predicted to increase as, sSFR(z) = (1 + z) 3 /t H0 , as observed (where t H0 is the Hubble time and no free parameters are necessary). In addition, the simple evolution for the star-formation intensity we propose is in agreement with observations of Milky Way-like galaxies selected through abundance matching. At z > ∼ 2, we argue that star formation is self-regulated by high pressures generated by the intense star formation itself. The star formation intensity must be high enough to either balance the hydrostatic pressure (a rather extreme assumption) or to generate high turbulent pressure in the molecular medium which maintains galaxies near the line of instability (i.e. Toomre Q ∼ 1). We provide simple prescriptions for understanding these self-regulation mechanisms based on solid relationships verified through extensive study. In all cases, the most important factor is the increase in stellar and gas mass surface density with redshift, which allows distant galaxies to maintain high levels of sSFR. Without a strong feedback from massive stars, such galaxies would likely reach very high sSFR levels, have high star formation efficiencies, and because strong feedback drives outflows, ultimately have an excess of stellar baryons.

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The Gravitational Potential Near the Sun From Segue K-Dwarf Kinematics

Cited by 152 publications

References 45 publications

The Besançon Galaxy model renewed

The Besançon Galaxy model renewed

The Milky Way's rotation curve out to 100 kpc and its constraint on the Galactic mass distribution

On the cosmic evolution of the specific star formation rate

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