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’s Parkes 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
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

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”
Added for Miller lecture

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”
Added for Miller lecture

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

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 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

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 galaxy NGC4038-9

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

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

17. Binary AGN
PKS
3C442
3C338

18. Suspected SMBH binaries
(Rodriguez et al. 2006)
Sarah Burke

19. Suspected SMBH binaries
3C66B (Sudou et al. 2003, debunked by Jenet et al. 2004)
2.3 GHz
Sarah Burke
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. Periodic outburst
Hercules A
PKS