scholarly journals ISOTROPIC AT THE BREAK? 3D KINEMATICS OF MILKY WAY HALO STARS IN THE FOREGROUND OF M31

2016 ◽  
Vol 820 (1) ◽  
pp. 18 ◽  
Author(s):  
Emily C. Cunningham ◽  
Alis J. Deason ◽  
Puragra Guhathakurta ◽  
Constance M. Rockosi ◽  
Roeland P. van der Marel ◽  
...  
Keyword(s):  
Milky Way ◽  
3D Kinematics ◽  
Halo Stars ◽  
Milky Way Halo

scholarly journals FOLLOWING THE COSMIC EVOLUTION OF PRISTINE GAS. I. IMPLICATIONS FOR MILKY WAY HALO STARS

2016 ◽  
Vol 834 (1) ◽  
pp. 23 ◽  
Author(s):  
Richard Sarmento ◽  
Evan Scannapieco ◽  
Liubin Pan
Keyword(s):  
Milky Way ◽  
Halo Stars ◽  
Cosmic Evolution ◽  
Milky Way Halo

scholarly journals Chemical Evolution of R-process Elements in the Hierarchical Galaxy Formation

2015 ◽  
Vol 11 (S317) ◽  
pp. 318-319
Author(s):  
Yutaka Komiya ◽  
Toshikazu Shigeyama
Keyword(s):  
Neutron Star ◽  
Chemical Evolution ◽  
Galaxy Formation ◽  
Milky Way ◽  
Galactic Chemical Evolution ◽  
Halo Stars ◽  
R Process ◽  
Process Elements ◽  
Milky Way Halo

AbstractThe main astronomical source of r-process elements has not yet been identified. One plausible site is neutron star mergers (NSMs). From the perspective of Galactic chemical evolution, however, it has been pointed out that the NSM scenario is incompatible with observations. Recently, Tsujimoto & Shigeyama (2014) pointed out that NSM ejecta can spread into much larger volume than ejecta from a supernova. We re-examine the chemical evolution of r-process elements under the NSM scenario considering this difference in propagation of the ejecta. We find that the NSM scenario can be compatible with the observed abundances of the Milky Way halo stars.

scholarly journals THE VELOCITY ANISOTROPY OF DISTANT MILKY WAY HALO STARS FROMHUBBLE SPACE TELESCOPEPROPER MOTIONS

2013 ◽  
Vol 766 (1) ◽  
pp. 24 ◽  
Author(s):  
A. J. Deason ◽  
R. P. Van der Marel ◽  
P. Guhathakurta ◽  
S. T. Sohn ◽  
T. M. Brown
Keyword(s):  
Milky Way ◽  
Velocity Anisotropy ◽  
Halo Stars ◽  
Milky Way Halo

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 The mass of the Milky Way out to 100 kpc using halo stars

2020 ◽  
Author(s):  
Alis J Deason ◽  
Denis Erkal ◽  
Vasily Belokurov ◽  
Azadeh Fattahi ◽  
Facundo A Gómez ◽  
...  
Keyword(s):  
Distribution Function ◽  
Mass Concentration ◽  
Milky Way ◽  
Function Analysis ◽  
Large Magellanic Cloud ◽  
Systematic Bias ◽  
Cosmological Simulations ◽  
Halo Stars ◽  
Systematic Effects ◽  
Mass Estimate

Abstract We use a distribution function analysis to estimate the mass of the Milky Way out to 100 kpc using a large sample of halo stars. These stars are compiled from the literature, and the vast majority ($\sim \! 98\%$) have 6D phase-space information. We pay particular attention to systematic effects, such as the dynamical influence of the Large Magellanic Cloud (LMC), and the effect of unrelaxed substructure. The LMC biases the (pre-LMC infall) halo mass estimates towards higher values, while realistic stellar halos from cosmological simulations tend to underestimate the true halo mass. After applying our method to the Milky Way data we find a mass within 100 kpc of M( < 100kpc) = 6.07 ± 0.29(stat.) ± 1.21(sys.) × 1011M⊙. For this estimate, we have approximately corrected for the reflex motion induced by the LMC using the Erkal et al. model, which assumes a rigid potential for the LMC and MW. Furthermore, stars that likely belong to the Sagittarius stream are removed, and we include a 5% systematic bias, and a 20% systematic uncertainty based on our tests with cosmological simulations. Assuming the mass-concentration relation for Navarro-Frenk-White haloes, our mass estimate favours a total (pre-LMC infall) Milky Way mass of M200c = 1.01 ± 0.24 × 1012M⊙, or (post-LMC infall) mass of M200c = 1.16 ± 0.24 × 1012 M⊙ when a 1.5 × 1011M⊙ mass of a rigid LMC is included.

Evidence of a Dwarf Galaxy Stream Populating the Inner Milky Way Halo

2021 ◽  
Vol 920 (1) ◽  
pp. 51
Author(s):  
Khyati Malhan ◽  
Zhen Yuan ◽  
Rodrigo A. Ibata ◽  
Anke Arentsen ◽  
Michele Bellazzini ◽  
...  
Keyword(s):  
Milky Way ◽  
Dwarf Galaxy ◽  
Milky Way Halo

scholarly journals Are there MACHOs in the Milky Way halo?

2002 ◽  
Vol 395 (1) ◽  
pp. 31-35 ◽  
Author(s):  
A. M. Green ◽  
K. Jedamzik
Keyword(s):  
Milky Way ◽  
Milky Way Halo

scholarly journals The escape speed curve of the Galaxy obtained from Gaia DR2 implies a heavy Milky Way

2018 ◽  
Vol 616 ◽  
pp. L9 ◽  
Author(s):  
G. Monari ◽  
B. Famaey ◽  
I. Carrillo ◽  
T. Piffl ◽  
M. Steinmetz ◽  
...  
Keyword(s):  
Mass Concentration ◽  
Milky Way ◽  
Galactic Centre ◽  
High Concentration ◽  
Circular Velocity ◽  
Halo Stars ◽  
Dark Matter Mass ◽  
The Galaxy ◽  
Escape Speed ◽  
Gaia Dr2

We measure the escape speed curve of the Milky Way based on the analysis of the velocity distribution of ~2850 counter-rotating halo stars from the Gaia Data Release 2. The distances were estimated through the StarHorse code, and only stars with distance errors smaller than 10% were used in the study. The escape speed curve is measured at Galactocentric radii ranging from ~5 kpc to ~10.5 kpc. The local Galactic escape at the Sun’s position is estimated to be ve(r⊙) = 580 ± 63 km s−1, and it rises towards the Galactic centre. Defined as the minimum speed required to reach three virial radii, our estimate of the escape speed as a function of radius implies for a Navarro–Frenk–White profile and local circular velocity of 240 km s−1 a dark matter mass M200 = 1.28−0.50+0.68 × 1012 M⊙ and a high concentration c200 = 11.09−1.79+2.94. Assuming the mass-concentration relation of ΛCDM, we obtain M200 = 1.55−0.51+0.64 × 1012 M⊙ and c200 = 7.93−0.27+0.33 for a local circular velocity of 228 km s−1.

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