The ARTEMIS simulations: stellar haloes of Milky Way-mass galaxies

Understand

We introduce the ARTEMIS simulations, a new set of 42 zoomed-in, high-resolution (baryon particle mass of ~ 2x10^4 Msun/h), hydrodynamical simulations of galaxies residing in haloes of Milky Way mass, simulated with the EAGLE galaxy formation code with re-calibrated stellar feedback.

• In this study, we analyse the structure of stellar haloes, specifically the mass density, surface brightness, metallicity, colour and age radial profiles, finding generally very good agreement with recent observations of local galaxies.
• The stellar density profiles are well fitted by broken power laws, with inner slopes of ~ -3, outer slopes of ~ -4 and break radii that are typically ~ 20-40 kpc.
• The break radii generally mark the transition between in situ formation and accretion-driven formation of the halo.