Special TAPIR Seminar

In person: 370 Cahill. To Join via Zoom: 868 5298 8404

ABSTRACT: Globular clusters (GCs) are amongst the oldest and densest stellar systems in the Universe, yet how they form remains an enduring puzzle. I will present a suite of state-of-the-art cosmological simulations in which both dark matter-free GCs and dark matter rich dwarf galaxies naturally emerge in LCDM. I show that these objects inhabit distinct locations in the size-luminosity plane and that they have a similar ages, age-spread, metallicity and metallicity-spread to GCs and dwarfs in the nearby Universe.

While half of GCs form through standard star formation, the rest are triggered by mergers; these "merger-born" clusters are more isolated and likely to survive. Using N-body simulations, I show that surviving GCs can tidally evolve into the extreme size-luminosity regions occupied by unclassified objects. I predict these objects will have high metallicity ([Fe/H]>-2) with low spreads. Finally, I introduce "globular cluster-like dwarfs" (GCDs)—objects that have formed within low-mass halos at high redshift (z>5) that bridge the gap between GCs and dwarfs. I discuss how GCDs can be used to probe dark matter and the first metal-free stars.