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

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

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

CSIRO’s Parkes Radio Telescope – 1961 Quasars Black holes

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 See the Introduction to the First Texas Symposium (1963) for an excellent and accurate description of how the discovery of quasars made black holes acceptable for the first time. edited

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” Added for Miller lecture

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” Added for Miller lecture

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)

Galactic Centre SgrA* 3x106 Mo

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

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

Radio Galaxies and QSO Radio Galaxies A Blackhole ? Jets from nucleus HST resolves accretion disk Rotation velocity 109 Mo Now widely accepted AGN’s called QSO’s here to simplify terminology in Miller talk

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

Binary galaxy NGC4038-9

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

Suspected SMBH binaries 3C75-type sources: wide binaries Sarah Burke

Binary AGN PKS2359-159 3C442 3C338

Suspected SMBH binaries 0402+379 (Rodriguez et al. 2006) Sarah Burke

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

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

NGC326

X sources

Periodic outburst Hercules A PKS0637-752