Abstract
I review the latest broad ranging evidence for dark matter, including our lensing work with the Hubble, indicating firmly that dark matter is cold (non-relativistic) and non-baryonic. However, the standard fermionic, TeV particle interpretation of cold dark matter (CDM) is now excluded by the LUX direct detection experiment and has been under pressure for many years from astronomical observations. I show with the first 3D cosmological simulations how a cold condensate state of matter provides a natural interpretation of the coldness of dark matter and of the anomalous properties of dwarf galaxies, by virtue of a Jeans Scale inherent to light bosonic matter in a cold condensate state. Bosons rather than Fermions are arguably much more natural contenders for dark matter generated by early symmetry breaking of inflationary scalar fields. Our simulations show that galaxies formed in this cold, wavelike state of matter have massive soltonic waves in their centers - providing a good explanation for the properties of dwarf spheroidal galaxies, and also for the star cluster at the center of the Milky Way. Our simulations predict that dark matter halos of regular galaxies are granular, comprised of stationary density waves. This lumpiness on Kpc scales we find can account for the well known flux anomalies of lensed QSO's. We are also testing the prediction that galaxy formation is delayed in this context, with the deepest “Frontier Field” imaging of the highest redshift galaxies detectable with Hubble. This new picture of dark matter is arguably now the most viable interpretation of CDM and provides a wealth of research possibilities for graduate students at HKU interested in observational and theoretical cosmology.
Coffee and tea will be served 20 minutes prior to the seminar.