Circumbinary Accretion: From Supermassive Binary Black Holes to Circumbinary Planets

Circumbinary disks have been observed in a number of young stellarsystems, and are the birth place for circumbinary planets found by theKepler misssion. They are also expected to exist around supermassiveblack hole binaries as a consequence of accretion from theinterstellar medium following galaxy mergers. I will discuss recent works on numerical modeling of circumbinary accretion, focusingshort-term and long-term variabilities, and angular momentum transferbetween the disk and the binary -- the result suggests that thelong-standing notion of binary orbital decay driven by circumbinarydisk may be problematic. Implications for planet formation/migrationaround stellar binaries will be noted. I will also discuss thedynamics and evolution of inclined/warped disks in binaries andconnect with recent observations of protoplanetary disks andcircumbinary planets.