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| - The escape speed curve of the Galaxy obtained from Gaia DR2 implies a heavy Milky Way
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| - 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 × 10 12 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 × 10 12 M⊙ and c200 = 7.93 −0.27+0.33 for a local circular velocity of 228 km s −1.
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