ITC Colloquium - Jorge Penarrubia (U Edinburgh) and Kishalay De (Caltech)


Thursday, October 8, 2020, 11:00am to 12:00pm

Location: Password: ITC
  1. Jorge Penarrubia (U Edinburgh)  "Impact of `dark' microhaloes on the dynamics of stars & planetary systems"

    In the current cosmological paradigm (Cold Dark Matter, CDM), galaxies like the Milky Way are teeming with dark matter substructures with masses as low as that of Earth (M~10^{-6} Msol), or even of asteroids (M~10^{-12} Msol). These objects do not contain baryons, and can only be detected through their gravitational attraction. However, to date it remains unclear to what extent such puny microhaloes affect the motion of visible objects.
    In this talk, I will introduce a Monte-Carlo N-body method that mimics the gravitational forces induced by a large population of dark substructures with known mass and size functions, and show that the tidal field of CDM haloes is dominated by the smallest (and most abundant) microhaloes.
    In view of this result, I will discuss the possibility to use Gaia observations of loosely-bound objects, such as co-moving stars and Oort clouds, to investigate the energy scale at which DM deviates from a perfect fluid and put constraints on a large range of particle candidates.
  1. Kishalay De (Caltech)
See also: Colloquium, 2020-21