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

Understand

We measure the escape speed curve of the Milky Way based on the analysis of the velocity distribution of $\sim 2850$ counter-rotating halo stars from the Gaia DR2.

• The distances were estimated through the StarHorse code, and only stars with distance errors smaller than 10 per cent were used in the study.
• The escape speed curve is measured at Galactocentric radii ranging from $\sim 5$ kpc to $\sim 10.5$ kpc.
• The local Galactic escape at the Sun's position is estimated to be $v_\mathrm{e}(r_\odot)=580 \pm 63~\mathrm{km~s^{-1}}$, and it rises towards the Galactic center.