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SUMMARY:Uncovering the nature of dark matter with stellar streams in the M
 ilky Way - Ana Bonaca (Harvard)
DTSTART:20200430T150000Z
DTEND:20200430T160000Z
UID:TALK141676@talks.cam.ac.uk
CONTACT:Dr Annelies Mortier
DESCRIPTION:Stars orbiting in the halo of our galaxy\, the Milky Way\, are
  a window into the distribution of dark matter. Tidally disrupting star cl
 usters are especially valuable tracers\, because in pristine conditions th
 ey produce thin stellar streams of nearly uniform density. I will present 
 maps of stellar streams based on the latest photometric and astrometric da
 ta that reveal variations in the width and density of streams -- typical s
 ignatures of dynamical perturbation. Dynamical modeling of a perturbed str
 eam GD-1 suggests it recently had a close encounter with a massive and den
 se perturber\, while precise radial velocities constrain the perturber's o
 rbit and present-day location. Known baryonic objects are unlikely perturb
 ers based on their orbital properties\, but observations permit a low-mass
  dark-matter subhalo as a plausible candidate. Data being delivered by big
  ground-based surveys of this decade (e.g.\, DESI\, LSST) will enable such
  studies in hundreds of stellar streams. I will discuss how the upcoming o
 bservations can be used to measure the mass spectrum of dark-matter substr
 uctures and even identify individual substructures and their orbits in the
  Milky Way halo. \n
LOCATION:ONLINE - Details will be sent by email
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