Orbital motion in the radio galaxy 3C 66B: evidence for a supermassive black hole binary.
23 May 2003-Science (American Association for the Advancement of Science)-Vol. 300, Iss: 5623, pp 1263-1265
TL;DR: Using the very-long-baseline interferometer, it is found that the unresolved radio core of 3C 66B shows well-defined elliptical motions with a period of 1.05 ± 0.03 years, which provides a direct detection of a supermassive black hole binary.
Abstract: Supermassive black hole binaries may exist in the centers of active galactic nuclei such as quasars and radio galaxies, and mergers between galaxies may result in the formation of supermassive binaries during the course of galactic evolution. Using the very-long-baseline interferometer, we imaged the radio galaxy 3C 66B at radio frequencies and found that the unresolved radio core of 3C 66B shows well-defined elliptical motions with a period of 1.05 ± 0.03 years, which provides a direct detection of a supermassive black hole binary.
Citations
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TL;DR: The current status of supermassive black hole research, as seen from a purely observational standpoint, can be found in this article, where the authors present a review of the state of the art.
Abstract: This review discusses the current status of supermassive black hole research, as seen from a purely observational standpoint Since the early ‘90s, rapid technological advances, most notably the launch of the Hubble Space Telescope, the commissioning of the VLBA and improvements in near-infrared speckle imaging techniques, have not only given us incontrovertible proof of the existence of supermassive black holes, but have unveiled fundamental connections between the mass of the central singularity and the global properties of the host galaxy It is thanks to these observations that we are now, for the first time, in a position to understand the origin, evolution and cosmic relevance of these fascinating objects
860 citations
Additional excerpts
...The existence of a SBH binary has also recently been claimed in the radio galaxy 3C 66, based on the positional change of the radio core detected in VLBI observations (Sudou et al. 2003)....
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Commonwealth Scientific and Industrial Research Organisation1, McGill University2, Goddard Space Flight Center3, University of California, Berkeley4, Swinburne University of Technology5, University of Cagliari6, Max Planck Society7, Australia Telescope National Facility8, University of California, San Diego9, Cornell University10, National Radio Astronomy Observatory11, Pennsylvania State University12, University of British Columbia13, University of Amsterdam14, Curtin University15, University of Manchester16, University of Texas at Brownsville17, West Virginia University18, United States Naval Research Laboratory19, Peking University20, Leiden University21, Franklin & Marshall College22, University of Virginia23, Bryn Mawr College24, University of Wisconsin–Milwaukee25, Oberlin College26, University of Sydney27, Southwest University28
TL;DR: The International Pulsar Timing Array (IPTA) project as mentioned in this paper combines observations of pulsars from both northern and southern hemisphere observatories with the main aim of detecting ultra-low frequency (similar to 10(-9)-10(-8) Hz) gravitational waves.
Abstract: The International Pulsar Timing Array project combines observations of pulsars from both northern and southern hemisphere observatories with the main aim of detecting ultra-low frequency (similar to 10(-9)-10(-8) Hz) gravitational waves. Here we introduce the project, review the methods used to search for gravitational waves emitted from coalescing supermassive binary black-hole systems in the centres of merging galaxies and discuss the status of the project.
583 citations
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TL;DR: The main properties, demographics and applications of binary and millisecond radio pulsars are reviewed.
Abstract: We review the main properties, demographics and applications of binary and millisecond radio pulsars. Our knowledge of these exciting objects has greatly increased in recent years, mainly due to successful surveys which have brought the known pulsar population to over 1800. There are now 83 binary and millisecond pulsars associated with the disk of our Galaxy, and a further 140 pulsars in 26 of the Galactic globular clusters. Recent highlights include the discovery of the young relativistic binary system PSR J1906+0746, a rejuvination in globular cluster pulsar research including growing numbers of pulsars with masses in excess of 1.5M , a precise measurement of relativistic spin precession in the double pulsar system and a Galactic millisecond pulsar in an eccentric (e = 0.44) orbit around an unevolved companion.
532 citations
Cites methods from "Orbital motion in the radio galaxy ..."
...More recently, timing data from B1855+09 have been used to virtually rule out the existence of a proposed supermassive black hole as the explanation for the periodic motion seen at the centre of the radio galaxy 3C66B [358]....
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TL;DR: A review of the observational evidence for binary supermassive black holes (SBHs) and how they would evolve can be found in this paper, where a handful of systems (e.g., interacting galaxies; remnants of galaxy mergers) are now believed to contain two SBHs at projected separations of < 1kpc.
Abstract: Coalescence of binary supermassive black holes (SBHs) would constitute the strongest sources of gravitational waves to be observed by LISA. While the formation of binary SBHs during galaxy mergers is almost inevitable, coalescence requires that the separation between binary components first drop by a few orders of magnitude, due presumably to interaction of the binary with stars and gas in a galactic nucleus. This article reviews the observational evidence for binary SBHs and discusses how they would evolve. No completely convincing case of a bound, binary SBH has yet been found, although a handful of systems (e.g. interacting galaxies; remnants of galaxy mergers) are now believed to contain two SBHs at projected separations of <~ 1kpc. N-body studies of binary evolution in gas-free galaxies have reached large enough particle numbers to reproduce the slow, “diffusive” refilling of the binary’s loss cone that is believed to characterize binary evolution in real galactic nuclei. While some of the results of these simulations - e.g. the binary hardening rate and eccentricity evolution - are strongly N-dependent, others - e.g. the “damage” inflicted by the binary on the nucleus - are not. Luminous early-type galaxies often exhibit depleted cores with masses of ~ 1-2 times the mass of their nuclear SBHs, consistent with the predictions of the binary model. Studies of the interaction of massive binaries with gas are still in their infancy, although much progress is expected in the near future. Binary coalescence has a large influence on the spins of SBHs, even for mass ratios as extreme as 10:1, and evidence of spin-flips may have been observed.
284 citations
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TL;DR: In this paper, the authors use simple disk models for the circumbinary gas and for the binary-disk interaction to follow the orbital decay of SMBHBs with a range of total masses (M) and mass ratios (q), through physically distinct regions of the disk, until gravitational waves (GWs) take over their evolution.
Abstract: Supermassive black hole binaries (SMBHBs) in galactic nuclei are thought to be a common by-product of major galaxy mergers. We use simple disk models for the circumbinary gas and for the binary-disk interaction to follow the orbital decay of SMBHBs with a range of total masses (M) and mass ratios (q), through physically distinct regions of the disk, until gravitational waves (GWs) take over their evolution. Prior to the GW-driven phase, the viscous decay is generically in the stalled secondary-dominated regime. SMBHBs spend a non-negligible fraction of a fiducial time of 107 yr at orbital periods between days t orb yr, and we argue that they may be sufficiently common to be detectable, provided they are luminous during these stages. A dedicated optical or X-ray survey could identify coalescing SMBHBs statistically, as a population of periodically variable quasars, whose abundance obeys the scaling N var t ? var within a range of periods around t var~ tens of weeks. SMBHBs with M 107 M ?, with 0.5 ? 1.5, would probe the physics of viscous orbital decay, whereas the detection of a population of higher-mass binaries, with ? = 8/3, would confirm that their decay is driven by GWs. The lowest-mass SMBHBs (M 105-6 M ?) enter the GW-driven regime at short orbital periods, when they are already in the frequency band of the Laser Interferometric Space Antenna (LISA). While viscous processes are negligible in the last few years of coalescence, they could reduce the amplitude of any unresolved background due to near-stationary LISA sources. We discuss modest constraints on the SMBHB population already available from existing data, and the sensitivity and sky coverage requirements for a detection in future surveys. SMBHBs may also be identified from velocity shifts in their spectra; we discuss the expected abundance of SMBHBs as a function of their orbital velocity.
261 citations
References
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TL;DR: In this paper, the authors review dynamical search techniques, the robustness of the evidence, and BH demographics, and find that supermassive black holes are present in 20% of nearby E-Sbc galaxies.
Abstract: Dynamical searches reveal central dark objects with masses"" 106 to 109.5 M0 in the Galaxy, M31, M32, M87, NGC 3115, NGC 3377, NGC 4258, and NGC 4594. Indirect arguments suggest but do not prove that these are supermassive black holes (BHs) like those postulated as quasar engines. This paper reviews dynam ical search techniques, the robustness of the evidence, and BH demographics. Stellar-dynamical evidence is generally more robust than gas-dynamical evidence (gas velocities can be nongravitational), but gas measurements reach closer to the Schwarzschild radius, and in NGC 4258 they show a Keplerian rotation curve. A statistical survey finds BHs in ""20% of nearby E-Sbc galaxies, consistent with predictions based on quasar energetics. BH masses are proportional to the mass of the bulge component. Most candidates are inactive; in some cases, the abun dance of fuel is not easily reconciled with BH starvation. Flashes caused by the accretion of individual stars may provide a test of the BH picture. I Visiting Astronomer, Canada-France-Hawaii Telescope (CFHT), operated by the National Research Council of Canada, Ie Centre National de la Recherche Scientifique of France, and the University of Hawaii.
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TL;DR: In this article, ground-based observations of a complete sample of 10 of these infrared galaxies suggest that they represent the initial dust-enshrouded stages of quasars, and a second group of ultraluminous objects selected on the basis of warm infrared colors are found to be preferentially Seyfert galaxies.
Abstract: The Infrared Astronomical Satellite (IRAS) has discovered a class of ultraluminous infrared galaxies (L ir > 1012 L ⊙) that are bolometrically as luminous, and slightly more numerous than optically selected quasars in the local universe (z ≲ 0.2). Ground-based observations of a complete sample of 10 of these infrared galaxies suggest that they represent the initial dust-enshrouded stages of quasars. A second group of ultraluminous objects selected on the basis of ‘warm’ infrared colors are found to be preferentially Seyfert galaxies. We suggest that these ultraluminous ‘warm’ objects represent the transition phase between the infrared selected and optically selected quasars.
2,179 citations
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TL;DR: In this paper, a theory of interferometry and synthesis imaging analysis of the Interferometer Response Geometric Relationships and Polarimetry Antennas and Arrays Response of the receiving system Design of the Analog Receiving System Digital Signal Processing Very-Long-Baseline Interferometry Calibration and Fourier Transformation of Visibility Data Deconvolution, Adaptive Calibrration, and Applications Interferometers Techniques for Astrometry and Geodesy Propagation Effects Van Cittert-Zernike Theorem, Spatial Coherence, and
Abstract: Preface to the Second Edition Preface to the First Edition Introduction and Historical Review Introductory Theory of Interferometry and Synthesis Imaging Analysis of the Interferometer Response Geometric Relationships and Polarimetry Antennas and Arrays Response of the Receiving System Design of the Analog Receiving System Digital Signal Processing Very-Long-Baseline Interferometry Calibration and Fourier Transformation of Visibility Data Deconvolution, Adaptive Calibration, and Applications Interferometer Techniques for Astrometry and Geodesy Propagation Effects Van Cittert-Zernike Theorem, Spatial Coherence, and Scattering Radio Interference Related Techniques Principal Symbols Author Index Subject Index
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"Orbital motion in the radio galaxy ..." refers background in this paper
...dependence, because the excess path due to the ionosphere is proportional to TEC � −2 , where � is the observing frequency ( 15 )....
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TL;DR: In this article, the authors explore the possibility that some active galactic nuclei may contain two massive black holes in orbit about each other, which suggests a new interpretation for the observed bending and apparent precession of radio jets emerging from these objects.
Abstract: Most theoretical discussions of active galactic nuclei (including quasars) attribute their energy production either to an accreting black hole or to a precursor stage—for instance a dense star cluster or a supermassive star—whose inevitable end point is a massive black hole1. We explore here the possibility that some active nuclei may contain two massive black holes in orbit about each other. This hypothesis suggests a new interpretation for the observed bending2 and apparent precession3 of radio jets emerging from these objects and may indeed be verified through detection of the direct consequences of orbital motion.
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