Astronomy Colloquium

  The existence of spectacular low-surface-brightness features - remnants of past mergers - surrounding many galaxies has been known about for many decades.  A major accomplishment for more recent, large scale stellar surveys of the Milky Way has been the discovery of a multitude of debris from dead and dying small satellites encircling our Galaxy.  This talk will look at three questions that can be addressed by the properties of such debris: what is the orbit distribution of in falling satellites? what is the mass, shape and radial profile of our dark matter halo? and does our halo contain any stars that originally formed in our Galactic disk?