Accretion disk warping by resonant relaxation: The case of maser disk
  NGC4258
  The maser disk around the massive black hole (MBH) in active galaxy NGC 4258
exhibits an O(10 deg) warp on the O(0.1 pc) scale. The physics driving the warp
are still debated. Suggested mechanisms include torquing by relativistic frame
dragging or by radiation pressure. We propose here a new warping mechanism:
resonant torquing of the disk by stars in the dense cusp around the MBH. We
show that resonant torquing can induce such a warp over a wide range of
observed and deduced physical parameters of the maser disk.
