scholarly journals Constraining the Milky Way Mass Profile with Phase-space Distribution of Satellite Galaxies

2020 ◽  
Vol 894 (1) ◽  
pp. 10 ◽  
Author(s):  
Zhao-Zhou Li ◽  
Yong-Zhong Qian ◽  
Jiaxin Han ◽  
Ting S. Li ◽  
Wenting Wang ◽  
...  
Keyword(s):  
Phase Space ◽  
Milky Way ◽  
Space Distribution ◽  
Phase Space Distribution ◽  
Mass Profile ◽  
Satellite Galaxies

scholarly journals Frequency maps as a probe of secular evolution in the Milky Way

2012 ◽  
Vol 10 (H16) ◽  
pp. 349-349
Author(s):  
Monica Valluri
Keyword(s):  
Dark Matter ◽  
Distribution Function ◽  
Phase Space ◽  
Milky Way ◽  
Space Distribution ◽  
Compact Representation ◽  
Phase Space Distribution ◽  
Secular Evolution ◽  
Halo Stars ◽  
Stellar Halo

AbstractThe frequency analysis of the orbits of halo stars and dark matter particles from a cosmological hydrodynamical simulation of a disk galaxy from the MUGS collaboration (Stinson et al. 2010) shows that even if the shape of the dark matter halo is nearly oblate, only about 50% of its orbits are on short-axis tubes, confirming a previous result: under baryonic condensation all orbit families can deform their shapes without changing orbital type (Valluri et al. 2010). Orbits of dark matter particles and halo stars are very similar reflecting their common accretion origin and the influence of baryons. Frequency maps provide a compact representation of the 6-D phase space distribution that also reveals the history of the halo (Valluri et al. 2012). The 6-D phase space coordinates for a large population of halo stars in the Milky Way that will be obtained from future surveys can be used to reconstruct the phase-space distribution function of the stellar halo. The similarity between the frequency maps of halo stars and dark matter particles (Fig. 1) implies that reconstruction of the stellar halo distribution function can reveal the phase space distribution of the unseen dark matter particles and provide evidence for secular evolution. MV is supported by NSF grant AST-0908346 and the Elizabeth Crosby grant.

scholarly journals Satellite galaxies as better tracers of the Milky Way halo mass

2019 ◽  
Vol 14 (S353) ◽  
pp. 109-112
Author(s):  
Jiaxin Han ◽  
Wenting Wang ◽  
Zhaozhou Li
Keyword(s):  
Dark Matter ◽  
Steady State ◽  
Phase Space ◽  
Milky Way ◽  
Space Structure ◽  
Space Distribution ◽  
Halo Stars ◽  
Satellite Galaxies ◽  
State Models ◽  
Milky Way Halo

AbstractThe inference of the Milky Way halo mass requires modelling the phase space structure of dynamical tracers, with different tracers following different models and having different levels of sensitivity to the halo mass. For steady-state models, deviations from steady-state in the tracer distribution lead to an irreducible stochastic bias. This bias is small for satellite galaxies and dark matter particles, but as large as a factor of 2 for halo stars. This is consistent with the picture that satellite galaxies closely trace the underlying phase space distribution of dark matter particles, while halo stars are less phase-mixed. As a result, the use of only ~100 satellite galaxies can achieve a significantly higher accuracy than that achievable with a much larger sample of halo stars.

scholarly journals A Versatile and Accurate Method for Halo Mass Determination from Phase-space Distribution of Satellite Galaxies

2019 ◽  
Vol 886 (1) ◽  
pp. 69 ◽  
Author(s):  
Zhao-Zhou Li ◽  
Yong-Zhong Qian ◽  
Jiaxin Han ◽  
Wenting Wang ◽  
Y. P. Jing
Keyword(s):  
Phase Space ◽  
Accurate Method ◽  
Space Distribution ◽  
Mass Determination ◽  
Phase Space Distribution ◽  
Satellite Galaxies

scholarly journals Quantifying torque from the Milky Way bar using Gaia DR2

2020 ◽  
Vol 494 (3) ◽  
pp. 3358-3367 ◽  
Author(s):  
Rain Kipper ◽  
Peeter Tenjes ◽  
Taavi Tuvikene ◽  
Punyakoti Ganeshaiah Veena ◽  
Elmo Tempel
Keyword(s):  
Phase Space ◽  
Milky Way ◽  
Space Distribution ◽  
Gravitational Acceleration ◽  
The Sun ◽  
Solar Mass ◽  
Stellar Orbits ◽  
Phase Space Distribution ◽  
Acceleration Field ◽  
Gaia Dr2

ABSTRACT We determine the mass of the Milky Way bar and the torque it causes, using Gaia DR2, by applying the orbital arc method. Based on this, we have found that the gravitational acceleration is not directed towards the centre of our Galaxy but a few degrees away from it. We propose that the tangential acceleration component is caused by the bar of the Galaxy. Calculations based on our model suggest that the torque experienced by the region around the Sun is $\approx 2400\, {\rm km^2\, s^{-2}}$ per solar mass. The mass estimate for the bar is $\sim 1.6\pm 0.3\times 10^{10}\, \mathrm{M_\odot }$. Using greatly improved data from Gaia DR2, we have computed the acceleration field to great accuracy by adapting the orbital Probability Density Function (oPDF) method (Han et al. 2016) locally and used the phase space coordinates of ∼4 × 105 stars within a distance of 0.5 kpc from the Sun. In the orbital arc method, the first step is to guess an acceleration field and then reconstruct the stellar orbits using this acceleration for all the stars within a specified region. Next, the stars are redistributed along orbits to check if the overall phase space distribution has changed. We repeat this process until we find an acceleration field that results in a new phase space distribution that is the same as the one that we started with; we have then recovered the true underlying acceleration.

A one-dimensional self-gravitating stellar gas

1966 ◽  
Vol 25 ◽  
pp. 46-48 ◽  
Author(s):  
M. Lecar
Keyword(s):  
Gravitational Field ◽  
Phase Space ◽  
Motion Picture ◽  
Space Distribution ◽  
Two Dimensional ◽  
One Dimensional ◽  
Phase Space Distribution ◽  
Dimensional Phase Space ◽  
The Mean

“Dynamical mixing”, i.e. relaxation of a stellar phase space distribution through interaction with the mean gravitational field, is numerically investigated for a one-dimensional self-gravitating stellar gas. Qualitative results are presented in the form of a motion picture of the flow of phase points (representing homogeneous slabs of stars) in two-dimensional phase space.

Simulation study of Landau damping near the persisting to arrested transition

2017 ◽  
Vol 83 (4) ◽  
Author(s):  
Alexander J. Klimas ◽  
Adolfo F. Viñas ◽  
Jaime A. Araneda
Keyword(s):  
Phase Space ◽  
Simulation Study ◽  
High Speed ◽  
Space Distribution ◽  
Landau Damping ◽  
Field Mode ◽  
Low Speed ◽  
Phase Space Distribution ◽  
Saturation Stage ◽  
First Time

A one-dimensional electrostatic filtered Vlasov–Poisson simulation study is discussed. The transition from persisting to arrested Landau damping that is produced by increasing the strength of a sinusoidal perturbation on a background Vlasov–Poisson equilibrium is explored. Emphasis is placed on observed features of the electron phase-space distribution when the perturbation strength is near the transition value. A single ubiquitous waveform is found perturbing the space-averaged phase-space distribution at almost any time in all of the simulations; the sole exception is the saturation stage that can occur at the end of the arrested damping scenario. This waveform contains relatively strong, very narrow structures in velocity bracketing $\pm v_{\text{res}}$ – the velocities at which electrons must move to traverse the dominant field mode wavelength in one of its oscillation periods – and propagating with $\pm v_{\text{res}}$ respectively. Local streams of electrons are found in these structures crossing the resonant velocities from low speed to high speed during Landau damping and from high speed to low speed during Landau growth. At the arrest time, when the field strength is briefly constant, these streams vanish. It is conjectured that the expected transfer of energy between electrons and field during Landau growth or damping has been visualized for the first time. No evidence is found in the phase-space distribution to support recent well-established discoveries of a second-order phase transition in the electric field evolution. While trapping is known to play a role for larger perturbation strengths, it is shown that trapping plays no role at any time in any of the simulations near the transition perturbation strength.

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