A Gaia-Enceladus analogue in the EAGLE simulation: insights into the early evolution of the Milky Way

Lucas A. Bignone, Amina Helmi, Patricia B. Tissera

Published 2019-08-19Version 1

We identify a simulated Milky Way-analogue in the \eagle{} suite of cosmological hydrodynamical simulations. This galaxy not only shares similar global properties as the Milky Way, but was specifically selected because its merger history resembles that currently known for the Milky Way. In particular we find that this Milky Way analogue has experienced its last significant merger (with a stellar mass ratio $\sim 0.2$) at $z\sim 1.2$. We show that this merger affected both the dynamical properties of the stars present at the time, contributing to the formation of a thick disk, and also leading to a significant increase in the star formation rate of the host. This object is thus particularly suitable for understanding the early evolutionary history of the Milky Way. It is also an ideal candidate for resimulation with much higher resolution as this would allow addressing a plethora of interesting questions such as for example the specific distribution of dark matter near the Sun.