On rapid migration and accretion within discs around supermassive black holes

B. Mckernan, K. E.S. Ford, W. Lyra, Hagai Perets, L. M. Winter, T. Yaqoob

Research output: Contribution to journalArticlepeer-review


Galactic nuclei should contain a cluster of stars and compact objects in the vicinity of the central supermassive black hole due to stellar evolution, minor mergers and gravitational dynamical friction. By analogy with protoplanetary migration, nuclear cluster objects (NCOs) can migrate in the accretion discs that power active galactic nuclei (AGN) by exchanging angular momentum with disc gas. Here we show that anindividualNCO undergoing runaway outward migration comparable to type III protoplanetary migration can generate an accretion rate corresponding to Seyfert AGN or quasar luminosities. Multiple migrating NCOs in an AGN disc can dominate traditional viscous disc accretion, and at large disc radii, ensemble NCO migration and accretion could provide sufficient heating to prevent the gravitational instability from consuming disc gas in star formation. The magnitude and energy of the X-ray soft excess observed at ~0.1-1keV in Seyfert AGN could be explained by a small population of ~102-103 accreting stellar mass black holes or a few ULXs. NCO migration and accretion in AGN discs are therefore extremely important mechanisms to add to realistic models of AGN discs.

Original languageEnglish
Pages (from-to)L103-L107
JournalMonthly Notices of the Royal Astronomical Society: Letters
Issue number1
StatePublished - Oct 2011
Externally publishedYes


  • Accreation, accreation discs
  • Galaxies: active
  • Galaxies: nuclei
  • Planet-disc interactions
  • Quasars: general
  • Stars: kinematics and dynamics

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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