Details

Autor(en) / Beteiligte

• Deason, A. J.
• Belokurov, V.
• Evans, N. W.
• An, J.

Titel

Broken degeneracies: the rotation curve and velocity anisotropy of the Milky Way halo

Ist Teil von

• Monthly notices of the Royal Astronomical Society. Letters, 2012-07, Vol.424 (1), p.L44-L48

Ort / Verlag

Oxford, UK: Blackwell Publishing Ltd

Erscheinungsjahr

2012

Quelle

Wiley Online Library Journals Frontfile Complete

Beschreibungen/Notizen

• ABSTRACT We use distant blue horizontal branch stars with Galactocentric distances 16 < r < 48 kpc as kinematic tracers of the Milky Way dark halo. We model the tracer density as an oblate, power law embedded within a spherical power‐law potential. Using a distribution function method, we estimate the overall power‐law potential and the velocity anisotropy of the halo tracers. We measure the slope of the potential to be γ∼ 0.4, and the overall mass within 50 kpc is ∼4 × 1011 M⊙. The tracer velocity anisotropy is radially biased with β∼ 0.5, which is in good agreement with local solar neighbourhood studies. Our results provide an accurate outer circular velocity profile for the Milky Way and suggest a relatively high‐concentration dark matter halo (cvir∼ 20).