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Evidence from AGN for Binary Black Holes

Evidence from AGN for Binary Black Holes. Ron Ekers Sydney 12 Dec 2007. Summary. Evidence for Super Massive Black Holes Super massive: Mass > 10 6 Mo Evidence for Binary Black Holes Consequence of SMBH Mergers. Evidence for Super Massive Black Holes. AGN evidence Discovery of Quasars

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Evidence from AGN for Binary Black Holes

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  1. Evidence from AGN for Binary Black Holes Ron Ekers Sydney 12 Dec 2007

  2. Summary • Evidence for Super Massive Black Holes • Super massive: Mass > 106 Mo • Evidence for Binary Black Holes • Consequence of SMBH Mergers

  3. Evidence for Super Massive Black Holes • AGN evidence • Discovery of Quasars • Energy requirements explained by black holes • Direct Evidence • Galactic centre (3x106 Mo) • NGC4258 (4x107 Mo) • Indirect evidence • HST observations of rotating disks (109 Mo) • Cusps in the light distribution • SMBH – galaxy bulge correlation

  4. CSIRO’sParkes Radio Telescope – 1961 • Quasars • Black holes

  5. Discovery of Quasars (1963) • The Lunar Occultation of 3C273 • CSIRO’s Parkes Observatory identifies a strong radio source with a bright star • A few of these weird stars already known • variable light so “couldn’t be extragalactic” • Observational Cosmology is born • Gravitational Collapse and Relativistic Astrophysics • Dallas, Texas 1963 • only a black hole could provide the energy

  6. Black Holes • Chandrasekhar (1931) – paper rejected by ApJ • “A star of large mass cannot pass into the white dwarf stage, one is left speculating on other possibilities” • Eddington – the authority • “a star would have to go on radiating and radiating, and contracting and contracting….I think there should be a law of nature to stop matter behaving in this absurd way” • Oppenheimer (1939) – exercise in abstraction • “the star closes itself off from any communication…only its gravitational field persists”

  7. Black Holes • Chandrasekhar (1931) – paper rejected by ApJ • “A star of large mass cannot pass into the white dwarf stage, one is left speculating on other possibilities” • Eddington – the authority • “a star would have to go on radiating and radiating, and contracting and contracting….I think there should be a law of nature to stop matter behaving in this absurd way” • Oppenheimer (1939) – exercise in abstraction • “the star closes itself off from any communication…only its gravitational field persists”

  8. Evidence for Super Massive Black Holes • AGN evidence • Discovery of Quasars • Energy requirements explained by black holes • Direct Evidence • Galactic centre (3x106 Mo) • NGC4258 (4x107 Mo)

  9. Galactic Centre SgrA* 3x106 Mo

  10. VLBI High spatial resolution Maser High spectral resolution 4x107 Mo black hole NGC4258 water vapour maser

  11. Evidence for Super Massive Black Holes • AGN evidence • Discovery of Quasars • Energy requirements explained by black holes • Direct Evidence • Galactic centre (3x106 Mo) • NGC4258 (4x107 Mo) • Indirect evidence • HST observations of rotating disks (109 Mo) • Cusps in the light distribution • SMBH – galaxy bulge correlation

  12. Radio Galaxies and QSO • Radio Galaxies • Jets from nucleus • A Blackhole ? • HST resolves accretion disk • Rotation velocity • 109 Mo • Now widely accepted

  13. Evidence for Binary Black Holes • Merging Galaxies • Double Nuclei Galaxies • Spatial (0.1” = kpc) • Spectral (double AGB lines) • Double Nuclei AGN • Spatial down to VLBI scales (10-3 arcsec = pc) • Double Rotation Measure radio AGN • Bryan Gaensler • any spatial scale • Periodic Outbursts • Offset Nuclei • Proper Motions

  14. Binary galaxyNGC4038-9

  15. X-ray Suspected SMBH binaries • NGC6240 (Komossa et al. 2003) • Double nuclei starburst

  16. Suspected SMBH binaries • 3C75-type sources: wide binaries

  17. 3C442 PKS2359-159 3C338 Binary AGN

  18. Suspected SMBH binaries • 0402+379 (Rodriguez et al. 2006)

  19. Suspected SMBH binaries • 3C66B (Sudou et al. 2003, debunked by Jenet et al. 2004) 2.3 GHz 8.4 GHz

  20. Consequences of SMBH Mergers • Precessing jets • X sources • Gravity waves • Kicks • Asymmetry in final merger gives the merged bh a kick • In special conditions many 100 km/sec • Dynamical friction time scale > merger time scale • Electromagnetic pulses • Identifying LISA SMBH merger host galaxies • Needed to measure redshift

  21. NGC326

  22. X sources

  23. Hercules A PKS0637-752 Periodic outburst

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