Supermassive binary black holes in powerful AGN

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Supermassive binary black holes in powerful AGN

• Andrei Lobanov

Zeldovich-90 Cosmology and High Energy
Astrophysics
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Outline
A. Lobanov

• Questions of relativistic jets and binary SMBH
• Relativistic jets from binary SMBH the case
  of 3C345
• Binary SMBH and nuclear activity in galaxies

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Studies of black holes
A. Lobanov

• Black holes remain a fundamental challenge
• Their very existence is difficult to establish
  GW physics is likely to provide the
  ultimate evidence
• Direct imaging of immediate vicinity of BH is
  still out of reach
• Physical properties are best constrained (at
  the moment) by studies of the environment of
  SMBH on scales readily available to modern
  instruments 1) accretion disks, 2)
  relativistic outflows, 3) BLR, 4) nuclear
  stellar population and gas dynamics

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SMBH in a larger context
A. Lobanov

• SMBH are expected to form in the early
  Universe, in the course of multiple mergers
  of dark matter halos (hierarchical structure
  formation). Multiple SMBH may be common in
  galaxies.
• SMBH are seemingly present in all (or almost
  all) galaxies (Kormendy Richstone 1995)
• BH masses can be connected with stellar and gas
  dynamics in the nuclear regions (Tremaine
  etal. 2002, Gebhradt et al. 2000, )
• BH masses are correlated with radio emission
  (Ho 2002)
• SMBH are closely related to (just about) every
  aspect of galactic activity, and may be one
  of the most significant energy sources in the
  Universe.
• Activity depends critically on the availability
  of accreting gas may be connected to
  the presence of multiple SMBH in a host galaxy.
• Binary SMBH may be common in the most powerful
  AGN.

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Evidence for binary SMBH
A. Lobanov

• Optical variability OJ287 (Valtonen, Takalo)
• Kinematics of radio jets 3C273, 3C345,
  3C120 (Abraham, Romero)
• Double nuclei in galaxies (eg. Komossa et
  al. 2003)
• Weaker claims VLBI astrometry of 3C66A,
  double optical lines, X-shaped radiosources,
  etc.

(courtesy F. Owen)
(Merritt Ekers 2002)
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BBH in 3C345 Observations
A. Lobanov
Optical data 1965- (gt2500)
Radio data 1965- (gt3000) VLBI
data 1979- (gt280)
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Jets from binary SMBH
A. Lobanov
Sol, Pelletier, Asséo (1989), Lobanov Roland
(2004)

• Magnetically confined outflow from a binary
  SMBH. Jet components are produced by
  perturbations in the beam
• Explains both evolution of a feature in the
  jet and optical variability

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Properties of BBH in 3C345
A. Lobanov
(Lobanov Roland 2004)
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Jets from BBH
A. Lobanov

• Magnetically confined jets may preserve
  information about dynamics of BBH systems

Simulated VLBI images
3C273 VLBI at 86GHz
(Krichbaum et al. 2001)
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Jets from BBH
A. Lobanov

• The jet is a quasi-stationary, relativistic,
  magnetized flow originated from a binary SMBH
  system
• The bright feature moving inside the jet is
  produced by a smooth, threefold increase of
  particle density.
• No shocks or instabilities are required to
  reproduce the evolution of the moving feature and
  flux density and spectral variability of the core
  of the jet.

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Binary SMBH and AGN
A. Lobanov

• Nuclear activity in galaxies closely related to
  mergers
• Timescale of dynamic evolution of a binary SMBH
  can be much longer than the AGN phase
• Properties of AGN should then be related with
  the actual evolutionary stage of the binary
  SMBH

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Stage I Early merger
A. Lobanov
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Stage II Wide binary
A. Lobanov
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Stage III Close binary
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Stage IV Pre-coalescence
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AGN Luminosity and BBH
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AGN power increases
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AGN Luminosity and BBH
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Summary
A. Lobanov

• Binary SMBH are likely to be related closely to
  nuclear activity in AGN
• Magnetically confined relativistic outflows can
  contain information about the dynamics of
  binary SMBH
• Relativistic outflows are one of the tools of
  choice for studying SMBH (binary or not) in
  centers of galaxies.

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Title
A. Lobanov

• .