Astrophysical implications of binary black holes in BL Lacertae objects

Paolis, F. De; Ingrosso, G.; Nucita, A. A.

doi:10.1051/0004-6361:20020519

Cited by 23 publications

(26 citation statements)

References 33 publications

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“…Note, however, that due to internal disc warping and/or disc precession, some deviations from strict periodicity are likely to occur. The detection of helical jet paths in an increasing number of blazar sources [17,18,19,20] suggests that quasiperiodic variability -especially in those energy bands dominated by the jet, e.g., radio, X-and γ-ray -may also naturally arise as a consequence of differential Doppler boosting S ν (t) = δ(t) n S ′ ν for a periodically changing viewing angle, where δ(t) is the time-dependent Doppler factor, n ≥ 3, and S ν ' the spectral flux in the comoving frame [21,22]. For non-ballistic helical motion, classical travel time effects will then lead to a shortening of observable periods P obs with respect to the real physical driving period P such that…”

Section: Periodic Variability In Close Sbbhsmentioning

confidence: 99%

Supermassive binary black holes among cosmic gamma-ray sources

Rieger

2007

Astrophys Space Sci

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Supermassive binary black holes (SBBHs) are a natural outcome of galaxy mergers. Here we show that low-frequency (f ≤ 10 −6 Hz) quasi-periodic variability observed from cosmic blazar sources can provide substantial inductive support for the presence of close (d < ∼ 0.1 pc) SBBHs at their centers. It is argued on physical grounds that such close binary systems are likely to give rise to different (although not independent) periodicities in the radio, optical and X-ray/TeV regime, and, hence that detection of appropriate period ratios significantly corroborates the SBBH interpretation. This is illustrated for a binary model where optical longterm periodicity is related to accretion disk interactions, radio periodicity to Newtonian jet precession, and periodicities in the high energy bands to the orbital motion of the jet. We use the observed periodicities to constrain the properties for a sample of SBBH candidates including OJ 287 and AO 0235+16, and discuss the results within the context of jet activity and binary evolution.

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Section: Periodic Variability In Close Sbbhsmentioning

confidence: 99%

Supermassive binary black holes among cosmic gamma-ray sources

Rieger

2007

Astrophys Space Sci

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“…We have shown recently (cf., Rieger & Mannheim 2000, hereafter RM00; cf. also De Paolis et al 2002) that such a periodicity may be caused by orbital-driven helical motion, i.e. the orbital motion of the relativistic jet emerging from the less massive BH (with mass m) in a close binary system with an orbital period of the order of several years, i.e.…”

Section: Mkn 501mentioning

confidence: 99%

Helical Motion and the Origin of QPO in Blazar-type Sources

Rieger

2005

Chin. J. Astron. Astrophys.

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Recent observations and analysis of blazar sources provide strong evidence for (i) the presence of significant periodicities in their lightcurves and (ii) the occurrence of helical trajectories in their radio jets. In scenarios, where the periodicity is caused by differential Doppler boosting effects along a helical jet path, both of these facts may be naturally tied together. Here we discuss four possible driving mechanisms for the occurrence of helical trajectories: orbital motion in a binary system, Newtonian-driven jet precession, internal jet rotation and motion along a global helical magnetic field. We point out that for non-ballistic helical motion the observed period may appear strongly shortened due to classical travel time effects. Finally, the possible relevance of the above mentioned driving mechanisms is discussed for Mkn 501, OJ 287 and AO 0235+16.

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“…On this basis, Rieger & Mannheim (2000) (but see also De Paolis et al 2002, for a generalization to orbits with generic eccentricity values) have recently proposed a method to determine the orbital parameters of the binary system from the observed quantities, i.e. the signal periodicity P obs , the flux ratio f between maximum and minimum signal and the power law spectral index α of the photon flux.…”

Section: Signal Periodicity In the X-ray And γ-Ray Light Curves And Tmentioning

confidence: 99%

“…For example, at least three Mkn objects (Mkn 501, Mkn 421 and Mkn 766) reveal periodic behavior in the observed signal so that in recent studies they have been considered as possibly containing SMBHBs (see Rieger & Mannheim 2000;De Paolis et al 2002.…”

Section: Introductionmentioning

confidence: 99%

A super massive black hole binary in 3C 66B: Future observational perspectives

Paolis¹,

Ingrosso²,

Nucita³

2004

A&A

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Abstract. Supermassive black hole binaries (SMBHBs) may exist in the centers of galaxies and active galactic nuclei (AGN) and are expected to be fairly common in the Universe as a consequence of merging processes between galaxies. The existence of SMBHBs can be probed by looking for double nuclei in galaxy centers or, more easily, detecting periodic behavior in the observed radio light curves. In a recent paper, Sudou et al. (2003, Science, 300, 1263 announced the first direct observation of an SMBHB. Using VLBI observations they found that the unresolved radio core of the radio galaxy 3C 66B shows a well defined elliptical motion with a period of 1.05 ± 0.03 yr, implying the presence of a couple of massive black holes in the center of the galaxy. In the present paper we study the astrophysical implications of the existence of such an SMBHB in 3C 66B. In particular we focus on the information that can be obtained from detecting a signal periodicity either in the X-ray and/or γ-ray light curves as a consequence of the motion of the black holes. These observations could be used to extract further information on the physical parameters of the SMBHB and partially solve the system parameter degeneracy. The detection of the gravitational wave spectrum emitted by such system may be used to completely determine the physical parameters of the binary system.

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Astrophysical implications of binary black holes in BL Lacertae objects

Cited by 23 publications

References 33 publications

Supermassive binary black holes among cosmic gamma-ray sources

Supermassive binary black holes among cosmic gamma-ray sources

Helical Motion and the Origin of QPO in Blazar-type Sources

A super massive black hole binary in 3C 66B: Future observational perspectives

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