The massive black holes found at the centers of most galaxies, including our own, are believed to be the ashes of the fuel that powered quasars early in the life of universe. I will briefly review some of the astronomical evidence for these objects and then describe some of the exotic dynamical phenomena that originate in their vicinity, including hypervelocity stars, resonant dynamical relaxation, phase transitions, and lopsided stellar disks.
Mot(s) clés libre(s) : galaxies, Black holes, Star formation, Stellar dynamics

Over the past decade multi-wavelength observations have revealed the extraordinary ubiquity and diversity of star formation in galaxies, ranging over billionfold ranges in star formation rates (SFRs), whether expressed in absolute terms, or in terms of areally or mass-normalised SFRs. Considerable attention has been focussed on the high-density extremes in starbursts and galactic nuclei, but much can be learned as well from star formation in low-density regimes-- in the outermost discs of spiral galaxies, and in early-type galaxies, low surface brightness galaxies, and extreme dwarf galaxies. This talk will highlight recent observations of star formation in these disparate environments, and examine the common behaviours and physical clues that they reveal.
Mot(s) clés libre(s) : galaxies, Star formation