Seminar details
Date: 22.11.2022
Oliver Newton (CFT PAN)
Exploring the Local Group with constrained simulations
Abstract:
Exquisite observations of the galaxies in the Local Group – comprising
the Milky Way, M31, and a population with lower masses – have enhanced
our understanding of a variety of astrophysical processes. In this
highly non-linear regime, numerical simulations have proved essential to
model how these mechanisms affect the evolution of low-mass galaxies in
the unique and dynamic environment of the Local Group. This is best
studied in 'constrained' simulations, which embed Local Group analogues
in larger-scale structure that closely corresponds to observational
proxies. Using the new HESTIA suite of such simulations, I explore the
properties of low-mass haloes that can be found `in the field' of the
Local Group at z=0. The simulations predict the existence of a novel
class of field haloes that passed through the Milky Way and M31 at early
times. The unique trajectories of these 'Hermeian' haloes facilitate the
exchange of material between the Milky Way and M31, and the Hermeian
galaxies themselves show promise as targets for indirect dark matter
searches beyond the Milky Way virial radius. I also discuss the
populations of ultra-diffuse galaxies (UDGs) that form in HESTIA. These
highly elusive objects could provide useful insights into the nature of
dark matter and improve our understanding of the extremes of galaxy
evolution. I show that UDGs could account for as much as half of the
total population of field galaxies within 2.5 Mpc of the Local Group,
and several could be awaiting discovery in Sloan Digital Sky Survey data
that have already been collected.