Double—double radio galaxies: remnants of merged supermassive binary black holes

The activity of active galaxies may be triggered by the merging of galaxies, and present-day galaxies are probably the product of successive minor mergers. The frequent galactic mergers at high redshift imply that active galaxies harbour supermassive unequal-mass binary black holes at their centre at least once during their lifetime. The secondary black hole interacts and becomes coplanar with the accretion disc around the primary, inwardly spiralling toward their mass centre owing to the loss of orbital angular momentum to the disc mass outside the orbit of the secondary and/or to gravitational radiation. The binary black holes finally merge and form a more massive (post-merged) black hole at the centre. In this paper it is shown that the recently-discovered double-lobed FR II radio galaxies are the remnants of such supermassive binary black holes. The inwardly spiraling secondary black hole opens a gap in the accretion disc that increases with time when the loss of the orbital angular momentum via gravitational radiation becomes dominant. When the supermassive black holes merge, the inner accretion disc disappears and the gap becomes a big hole of several hundreds of Schwarzschild radii in the vicinity of the post-merged supermassive black hole, leading to an interruption of jet formation. When the outer accretion disc slowly refills the big hole on a viscous time-scale, jet formation restarts and the interaction of the recurrent jets and the inter-galactic medium forms a secondary pair of lobes. The model is applied to a particular double-lobed radio source -B 1834+620 - which has an interruption time-scale ∼Myr. It is shown that the orbit of the secondary in B1834+620 is elliptical with a typical eccentricity e≃ 0.68 and that the ratio q of the mass of the secondary to that of the primary is 0.01 ≤ q ≤ 0.4. The accretion disc is a standard α-disc with 0.01 ≤ α ≤ 0.04 and the ratio of disc half height H to radius r is δ ≃ 0.01. The model predicts that double-lobed radio structures form only in FR II or borderline FR I/FR II radio galaxies and that the detection rate of double-lobed radio sources among FR II radio sources is about one per cent.

[1]  Italy.,et al.  A new list of extra-galactic radio jets , 2002, astro-ph/0212477.

[2]  China.,et al.  Black hole mass and binary model for BL Lac object OJ 287 , 2002, astro-ph/0212475.

[3]  Xue-bing Wu,et al.  Supermassive black hole masses of AGNs with elliptical hosts , 2002, astro-ph/0203158.

[4]  India.,et al.  A Case for Renewed Activity in the Giant Radio Galaxy J0116?473 , 2002, astro-ph/0209570.

[5]  P. Armitage,et al.  Accretion during the Merger of Supermassive Black Holes , 2002, astro-ph/0201318.

[6]  M. Rees,et al.  Feeding black holes at galactic centres by capture from isothermal cusps , 2001, astro-ph/0112096.

[7]  R. Laing,et al.  Jet reorientation in AGN : two winged radio galaxies , 2001 .

[8]  J. Dunlop,et al.  On the black hole–bulge mass relation in active and inactive galaxies , 2001, astro-ph/0201081.

[9]  G. Ghisellini,et al.  The dividing line between fr I and fr II radio-galaxies , 2001, astro-ph/0106570.

[10]  A. Cavaliere,et al.  The Blazar Main Sequence , 2001, astro-ph/0106512.

[11]  C. Dermer,et al.  An Evolutionary Scenario for Blazar Unification , 2001, astro-ph/0106395.

[12]  V. Narayanan,et al.  The Merger History of Supermassive Black Holes in Galaxies , 2001, astro-ph/0101196.

[13]  D. Merritt,et al.  Black Hole Demographics from the M(BH)-sigma Relation , 2000, astro-ph/0009076.

[14]  D. Merritt,et al.  The M•-σ Relation for Supermassive Black Holes , 2000, astro-ph/0008310.

[15]  G. Kauffmann,et al.  The Correlation between black hole mass and bulge velocity dispersion in hierarchical galaxy formation models , 2000, astro-ph/0007369.

[16]  H. Röttgering,et al.  Radio galaxies with a 'double-double' morphology - III. The case of B 1834+620 , 2000 .

[17]  Ralf Bender,et al.  A Relationship between Nuclear Black Hole Mass and Galaxy Velocity Dispersion , 2000, astro-ph/0006289.

[18]  J. Mulchaey,et al.  The Properties of Poor Groups of Galaxies. III. The Galaxy Luminosity Function , 2000, astro-ph/0001495.

[19]  C. Kaiser,et al.  Radio galaxies with a ‘double-double’ morphology – II. The evolution of double-double radio galaxies and implications for the alignment effect in FRII sources , 1999, astro-ph/9912142.

[20]  H. Rix,et al.  Binary Black Hole Mergers from Planet-like Migrations , 1999, The Astrophysical journal.

[21]  R. Narayan.  Hydrodynamic Drag on a Compact Star Orbiting a Supermassive Black Hole , 1999, astro-ph/9907328.

[22]  G. Kauffmann,et al.  A unified model for the evolution of galaxies and quasars , 1999, astro-ph/9906493.

[23]  H. Rottgering,et al.  Radio galaxies with a 'double-double morphology' - I. Analysis of the radio properties and evidence for interrupted acti , 1999, astro-ph/9912141.

[24]  H. Rottgering,et al.  The radio source B 1834+620: A double-double radio galaxy with interesting properties , 1999, astro-ph/9912143.

[25]  J. Papaloizou,et al.  THE EVOLUTION OF A SUPERMASSIVE BINARY CAUSED BY AN ACCRETION DISC , 1998, astro-ph/9812198.

[26]  P. Natarajan,et al.  The Alignment of Disk and Black Hole Spins in Active Galactic Nuclei , 1998, astro-ph/9808187.

[27]  D. Vokrouhlický,et al.  Stellar capture by an accretion disc , 1997, astro-ph/9710169.

[28]  S. Tremaine,et al.  The Demography of Massive Dark Objects in Galaxy Centers , 1997, astro-ph/9708072.

[29]  J. E. Pringle,et al.  SELF-INDUCED WARPING OF ACCRETION DISCS : NON-LINEAR EVOLUTION AND APPLICATION TO AGN , 1997 .

[30]  C. Reynolds,et al.  Intermittent Radio Galaxies and Source Statistics , 1997 .

[31]  P. Scheuer,et al.  THE REALIGNMENT OF A BLACK HOLE MISALIGNED WITH ITS ACCRETION DISC , 1996 .

[32]  F. Owen,et al.  A 20cm VLA Survey of Abell Clusters of Galaxies VI. Radio/Optical Luminosity Functions , 1996, astro-ph/9607014.

[33]  G. Quinlan.  The dynamical evolution of massive black hole binaries i , 1996, astro-ph/9706298.

[34]  D. Syer,et al.  Satellites in discs: regulating the accretion luminosity , 1995, astro-ph/9505021.

[35]  O. Regev,et al.  Thermal equilibria of accretion disks , 1994, astro-ph/9409018.

[36]  Paul S. Smith,et al.  The optical polarization properties of X-ray-selected BL Lacertae objects , 1994 .

[37]  R. Narayan,et al.  Advection-dominated Accretion: A Self-similar Solution , 1994, astro-ph/9403052.

[38]  S. Lubow,et al.  Dynamics of binary-disk interaction. 1: Resonances and disk gap sizes , 1994 .

[39]  P. Artymowicz.  DYNAMICS OF BINARY AND PLANETARY SYSTEM INTERACTION WITH DISKS: ECCENTRICITY CHANGES , 1992 .

[40]  M. Norman,et al.  Origin of the structures and polarization in the classical double 3C 219 , 1992 .

[41]  J. Burns,et al.  Numerical simulations of a restarting jet , 1991 .

[42]  J. Pringle.  The properties of external accretion discs , 1991 .

[43]  E. Fomalont,et al.  The unusual radio galaxy 3C 288 , 1989 .

[44]  J. Lasota,et al.  Slim Accretion Disks , 1988 .

[45]  A. Sillanpää,et al.  OJ 287 - Binary pair of supermassive black holes , 1988 .

[46]  D. Lin,et al.  On the tidal interaction between protoplanets and the protoplanetary disk. III. Orbital migration of protoplanets , 1986 .

[47]  J. Pringle,et al.  Twisted accretion discs: The Bardeen–Petterson effect , 1985 .

[48]  J. Papaloizou,et al.  The time-dependence of non-planar accretion discs , 1983 .

[49]  D. Meier,et al.  Thick accretion disks - Self-similar, supercritical models , 1982 .

[50]  Peter Goldreich,et al.  Disk-Satellite Interactions , 1980 .

[51]  M. Rees,et al.  Massive black hole binaries in active galactic nuclei , 1980, Nature.

[52]  J. Riley,et al.  The Morphology of Extragalactic Radio Sources of High and Low Luminosity , 1974 .

[53]  J. Ables,et al.  Simultaneous observations of pulsar intensity variations at Parkes and Ootacamund. , 1974 .

[54]  J. Mathews,et al.  Gravitational radiation from point masses in a Keplerian orbit , 1963 .