Rotation Curve of the Milky Way from Classical Cepheids

Mróz, P.; Udalski, A.; Skowron, D. M.; Soszyński, I.; Szymański, M. K.; Poleski, R.; Ulaczyk, K.

doi:10.3847/2041-8213/aaf73f

Cited by 126 publications

(194 citation statements)

References 43 publications

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“…At the solar position we get a value of v circ (R ) = 236.5±1.8 km s −1 . This value also agrees well with the value of Eilers et al (2019) (229.0 ± 0.2 km s −1 ), where they use a quite different stellar sample, stellar distance estimates and modelling assumptions, and with another recent work by Mróz et al (2019) (233.6 ± 2.8 km s −1 ) in which they construct the rotation curve of the Milky Way using the proper motion and radial velocities from Gaia for classical Cepheids.…”

Section: Circular Velocity Curvesupporting

confidence: 90%

First Gaia dynamical model of the Milky Way disc with six phase space coordinates: a test for galaxy dynamics

Nitschai

Cappellari

Neumayer

2020

Monthly Notices of the Royal Astronomical Society

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We construct the first comprehensive dynamical model for the high-quality subset of stellar kinematics of the Milky Way disc, with full 6D phase-space coordinates, provided by the Gaia Data Release 2. We adopt an axisymmetric approximation and use an updated Jeans Anisotropic Modelling method, which allows for a generic shape and radial orientation of the velocity ellipsoid, as indicated by the Gaia data, to fit the mean velocities and all three components of the intrinsic velocity dispersion tensor. The Milky Way is the first galaxy for which all intrinsic phase space coordinates are available, and the kinematics are superior to the best integral-field kinematics of external galaxies. This situation removes the long-standing dynamical degeneracies and makes this the first dynamical model highly over-constrained by the kinematics. For these reasons, our ability to fit the data provides a fundamental test for both galaxy dynamics and the mass distribution in the Milky Way disc. We tightly constrain the average total density logarithmic slope, in the radial range 3.6-12 kpc, to be α tot = −2.149 ± 0.055 and find that the dark halo slope must be significantly steeper than α DM = −1 (NFW). The dark halo shape is close to spherical and its density is ρ DM (R ) = 0.0115 ± 0.0020 M pc −3 (0.437 ± 0.076 GeV cm −3 ), in agreement with previous estimates. The circular velocity at the solar position v circ R = 236.5 ± 3.1 km s −1 (including systematics) and its radial trends are also consistent with recent determinations.

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Section: Circular Velocity Curvesupporting

confidence: 90%

First Gaia dynamical model of the Milky Way disc with six phase space coordinates: a test for galaxy dynamics

Nitschai

Cappellari

Neumayer

2020

Monthly Notices of the Royal Astronomical Society

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“…However, the most intriguing property of dSphs is the fact that most of them are found near their pericenter (Fritz et al 2018;Simon 2018Simon , 2019, for an MW mass model consistent with its accurate rotation curve (Eilers et al 2019;Mróz et al 2019), with both results coming from Gaia DR2 studies. Cautun et al (2019) have attempted to supersede the Bovy (2015) MW mass model by using a contracted DM halo, but it does not fit the most external part of the MW rotation curve and increase by only 20% the MW total mass.…”

Section: Discussionmentioning

confidence: 95%

Orbital Evidences for Dark-matter-free Milky Way Dwarf Spheroidal Galaxies

Hammer

Yang

Arenou

et al. 2020

ApJ

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The nature of Milky Way dwarf spheroidals (MW dSphs) has been questioned, in particular whether they are dominated by dark matter (DM). Here we investigate an alternative scenario, for which tidal shocks are exerted by the MW to DM-free dSphs after a first infall of their gas-rich progenitors, and for which theoretical calculations have been verified by pure N-body simulations. Whether or not the dSphs are on their first infall cannot be resolved on the sole basis of their star formation history. In fact, gas removal may cause complex gravitational instabilities, and near-pericenter passages can give rise to tidal disruptive processes. Advanced precision with the Gaia satellite in determining both their past orbital motions and the MW velocity curve is however providing crucial results.First, tidal shocks explain why DM-free dSphs are found preferentially near their pericenter where they are in a destructive process, while their chance to be long-lived satellites is associated to a very low probability P∼ 2 ×10 −7 , which is at odds with the current DM-dominated dSph scenario. Second, most dSph binding energies are consistent with a first infall. Third, the MW tidal shocks that predict the observed dSph velocity dispersions are themselves predicted in amplitude by the most accurate MW velocity curve. Fourth, tidal shocks accurately predict the forces or accelerations exerted at half-light radius of dSphs, including the MW and the Magellanic System gravitational attractions.The above is suggestive of dSphs that are DM-free and tidally shocked near their pericenters, which may provoke a significant quake in our understanding of near-field cosmology.

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“…Although the Galaxy has features that are notably axially asymmetric, namely, the spiral arms and Galactic bar, it is nevertheless the case that f (J) modelling gives a very good description of the velocity distributions observed by the RAVE survey. With the advent of Gaia DR2 data (Prusti et al 2016;Lindegren et al 2018) it has become possible to determine the structure of the dark halo from the stars alone , in that the circular speed curve with the in-plane Galactic radius R from the reconstructed Galactic potential is compatible with the circular speed from Cepheids (Mróz et al 2019;Binney 2019).…”

Section: Introductionmentioning

confidence: 99%

Probing Axial Symmetry Breaking in the Galaxy with Gaia Data Release 2

Hinkel

Gardner

Yanny

2020

ApJ

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We study a set of solar neighborhood (d < 3 kpc) stars from Gaia Data Release 2 to determine azimuthal star count differences, i.e., left and right of the line from the Galactic center through the sun -and compare these differences north and south. In this companion paper to Gardner et al. (2020), we delineate our procedures to remove false asymmetries from sampling effects, incompleteness, and/or interloper populations, as this is crucial to tests of axisymmetry. Particularly, we have taken care to make appropriate selections of magnitude, color, in-plane Galactocentric radius and Galactic |b| and |z|. We find that requiring parallax determinations of high precision induces sampling biases, so that we eschew such requirements and exclude, e.g., regions around the lines of sight to the Magellanic clouds, along with their mirror-image lines of sight, to ensure well-matched data sets. After making conservative cuts, we demonstrate the existence of azimuthal asymmetries, and find differences in those, north and south. These asymmetries give key insights into the nature and origins of the perturbations on Galactic matter, allowing us to assess the relative influence of the Magellanic Clouds (LMC & SMC), the Galactic bar, and other masses on the Galactic mass distribution, as described in Gardner et al. (2020). The asymmetry's radial dependence reveals variations that we attribute to the Galactic bar, and it changes sign at a radius of (0.95 ± 0.03)R 0 , with R 0 the Sun-Galactic-Center (GC) distance, to give us the first direct assessment of the outer Lindblad resonant radius.

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Rotation Curve of the Milky Way from Classical Cepheids

Cited by 126 publications

References 43 publications

First Gaia dynamical model of the Milky Way disc with six phase space coordinates: a test for galaxy dynamics

First Gaia dynamical model of the Milky Way disc with six phase space coordinates: a test for galaxy dynamics

Orbital Evidences for Dark-matter-free Milky Way Dwarf Spheroidal Galaxies

Probing Axial Symmetry Breaking in the Galaxy with Gaia Data Release 2

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