Can Supermassive Black Holes alter Cold Dark Matter cusps through   accretion?
  We present some simple models to determine whether or not the accretion of cold dark matter by supermassive black holes is astrophysically important. Contrary to some claims in the literature, we show that supermassive black holes cannot significantly alter a power law density cusp via accretion, whether during mergers or in the steady state. 
J. I. Read and G. Gilmore