Binary black hole

Last updated
Computer simulation of the black hole binary system GW150914 as seen by a nearby observer, during its final inspiral, merge, and ringdown. The star field behind the black holes is being heavily distorted and appears to rotate and move, due to extreme gravitational lensing, as space-time itself is distorted and dragged around by the rotating black holes. [1]

A binary black hole (BBH), or black hole binary, is a system consisting of two black holes in close orbit around each other. Like black holes themselves, binary black holes are often divided into binary stellar black holes, formed either as remnants of high-mass binary star systems or by dynamic processes and mutual capture; and binary supermassive black holes, believed to be a result of galactic mergers.

Contents

For many years, proving the existence of binary black holes was made difficult because of the nature of black holes themselves and the limited means of detection available. However, in the event that a pair of black holes were to merge, an immense amount of energy should be given off as gravitational waves, with distinctive waveforms that can be calculated using general relativity. [2] [3] [4] Therefore, during the late 20th and early 21st century, binary black holes became of great interest scientifically as a potential source of such waves and a means by which gravitational waves could be proven to exist. Binary black hole mergers would be one of the strongest known sources of gravitational waves in the universe, and thus offer a good chance of directly detecting such waves. As the orbiting black holes give off these waves, the orbit decays, and the orbital period decreases. This stage is called binary black hole inspiral. The black holes will merge once they are close enough. Once merged, the single hole settles down to a stable form, via a stage called ringdown, where any distortion in the shape is dissipated as more gravitational waves. [5] In the final fraction of a second the black holes can reach extremely high velocity, and the gravitational wave amplitude reaches its peak.

The existence of stellar-mass binary black holes (and gravitational waves themselves) was finally confirmed when the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected GW150914 (detected September 2015, announced February 2016), a distinctive gravitational wave signature of two merging stellar-mass black holes of around 30 solar masses each, occurring about 1.3 billion light-years away. In its final 20 ms of spiraling inward and merging, GW150914 released around 3 solar masses as gravitational energy, peaking at a rate of 3.6×1049  watts  – more than the combined power of all light radiated by all the stars in the observable universe put together. [6] [7] [8] Supermassive binary black hole candidates have been found, but not yet categorically proven. [9]

Occurrence

Stellar-mass binary black holes have been demonstrated to exist, by the first detection of a black-hole merger event GW150914 by LIGO. [10]

In this visualization, a binary system containing two supermassive black holes and their accretion disks is initially viewed from above. After about 25 seconds, the camera dips closer to the orbital plane to reveal the lensing effects produced by their immense gravity. The different colors assigned to the accretion disks make it easier to visualize the complex optical distortions that would be seen by an outside observer. [11]

Supermassive black-hole (SMBH) binaries are believed to form during galaxy mergers. Some likely candidates for binary black holes are galaxies with double cores still far apart. An example active double nucleus is NGC 6240. [12] Much closer black-hole binaries are likely in single-core galaxies with double emission lines. Examples include SDSS J104807.74+005543.5 [13] and EGSD2 J142033.66 525917.5. [14] Other galactic nuclei have periodic emissions suggesting large objects orbiting a central black hole, for example, in OJ287. [15]

Measurements of the peculiar velocity of the mobile SMBH in the galaxy J0437+2456 indicate that it is a promising candidate for hosting either a recoiling or binary SMBH, or an ongoing galaxy merger. [16]

The quasar PKS 1302-102 appears to have a binary black hole with an orbital period of 1900 days. [17]

Final parsec problem

When two galaxies collide, the supermassive black holes at their centers are very unlikely to hit head-on and would most likely shoot past each other on hyperbolic trajectories, unless some mechanism brings them together. The most important mechanism is dynamical friction, which transfers kinetic energy from the black holes to nearby matter. As a black hole passes a star, the gravitational slingshot accelerates the star while decelerating the black hole.

This slows the black holes enough that they form a bound binary system, and further dynamical friction steals orbital energy from the pair until they are orbiting within a few parsecs of each other. However, this process also ejects matter from the orbital path, and as the orbits shrink, the volume of space the black holes pass through reduces, until there is so little matter remaining that it could not cause a merger within the age of the universe.

Gravitational waves can cause significant loss of orbital energy, but not until the separation shrinks to a much smaller value, roughly 0.01–0.001 parsec.

Nonetheless, supermassive black holes appear to have merged, and what appears to be a pair in this intermediate range has been observed in PKS 1302-102. [18] [19] The question of how this happens is the "final parsec problem". [20]

A number of solutions to the final parsec problem have been proposed. Most involve mechanisms to bring additional matter, either stars or gas, close enough to the binary pair to extract energy from the binary and cause it to shrink. If enough stars pass close by to the orbiting pair, their gravitational ejection can bring the two black holes together in an astronomically plausible time. [21] Dark matter is also being considered, although it appears that self-interacting dark matter is required to avoid the same problem of it all being ejected before the merger occurs. [22] [23]

One mechanism that is known to work, although infrequently, is a third supermassive black hole from a second galactic collision. [24] While it is possible that one of the three is ejected, their large masses make it more likely that one is not ejected, but instead the three have repeated interactions. The resultant chaotic orbits allow two additional energy loss mechanisms: [25]

  1. the black holes orbit through a substantially larger volume of the galaxy, interacting with (and losing energy to) a much greater amount of matter, and
  2. the orbits can become highly eccentric, allowing energy loss by gravitational radiation at the point of closest approach.

Lifecycle

Inspiral

The first stage of the life of a binary black hole is the inspiral , a gradually shrinking orbit. The first stages of the inspiral take a very long time, as the gravitational waves emitted are very weak when the black holes are distant from each other. In addition to the orbit shrinking due to the emission of gravitational waves, extra angular momentum may be lost due to interactions with other matter present, such as other stars.

As the black holes’ orbit shrinks, the speed increases, and gravitational wave emission increases. When the black holes are close the gravitational waves cause the orbit to shrink rapidly. [26]

The last stable orbit or innermost stable circular orbit (ISCO) is the innermost complete orbit before the transition from inspiral to merger. [27]

Merger

This is followed by a plunging orbit, in which the two black holes meet, followed by the merger. Gravitational wave emission peaks at this time. [27]

Ringdown

Immediately following the merger, the now single black hole will "ring". This ringing is damped in the next stage, called the ringdown, by the emission of gravitational waves. The ringdown phase starts when the black holes approach each other within the photon sphere. In this region most of the emitted gravitational waves go towards the event horizon, and the amplitude of those escaping reduces. Remotely detected gravitational waves have an oscillation with fast-reducing amplitude, as echos of the merger event result from tighter and tighter spirals around the resulting black hole. [28] [29]

Observation

The first observation of stellar-mass binary black holes merging, GW150914, was performed by the LIGO detector. [10] [30] [31] As observed from Earth, a pair of black holes with estimated masses around 36 and 29 times that of the Sun spun into each other and merged to form an approximately 62-solar-mass black hole on 14 September 2015, at 09:50 UTC. [32] Three solar masses were converted to gravitational radiation in the final fraction of a second, with a peak power 3.6×1056  erg/s (200 solar masses per second), [10] which is 50 times the total output power of all the stars in the observable universe. [33] The merger took place 440+160
−180  megaparsecs from Earth, [34] between 600 million and 1.8 billion years ago. [30] The observed signal is consistent with the predictions of numerical relativity. [2] [3] [4]

Dynamics modelling

Some simplified algebraic models can be used for the case where the black holes are far apart, during the inspiral stage, and also to solve for the final ringdown.

Post-Newtonian approximations can be used for the inspiral. These approximate the general-relativity field equations adding extra terms to equations in Newtonian gravity. Orders used in these calculations may be termed 2PN (second-order post-Newtonian) 2.5PN or 3PN (third-order post-Newtonian). Effective-one-body (EOB) approximation solves the dynamics of the binary black-hole system by transforming the equations to those of a single object. This is especially useful where mass ratios are large, such as a stellar-mass black hole merging with a galactic-core black hole, but can also be used for equal-mass systems.

For the ringdown, black-hole perturbation theory can be used. The final Kerr black hole is distorted, and the spectrum of frequencies it produces can be calculated.

Description of the entire evolution, including merger, requires solving the full equations of general relativity. This can be done in numerical relativity simulations. Numerical relativity models space-time and simulates its change over time. In these calculations it is important to have enough fine detail close into the black holes, and yet have enough volume to determine the gravitation radiation that propagates to infinity. In order to reduce the number of points such that the numerical problem is tractable in a reasonable time, special coordinate systems can be used, such as Boyer–Lindquist coordinates or fish-eye coordinates.

Numerical-relativity techniques steadily improved from the initial attempts in the 1960s and 1970s. [35] [36] Long-term simulations of orbiting black holes, however, were not possible until three groups independently developed groundbreaking new methods to model the inspiral, merger, and ringdown of binary black holes [2] [3] [4] in 2005.

In the full calculations of an entire merger, several of the above methods can be used together. It is then important to fit the different pieces of the model that were worked out using different algorithms. The Lazarus Project linked the parts on a spacelike hypersurface at the time of the merger. [37]

Results from the calculations can include the binding energy. In a stable orbit the binding energy is a local minimum relative to parameter perturbation. At the innermost stable circular orbit the local minimum becomes an inflection point.

The gravitational waveform produced is important for observation prediction and confirmation. When inspiralling reaches the strong zone of the gravitational field, the waves scatter within the zone producing what is called the post-Newtonian tail (PN tail). [37]

In the ringdown phase of a Kerr black hole, frame-dragging produces a gravitation wave with the horizon frequency. In contrast, the Schwarzschild black-hole ringdown looks like the scattered wave from the late inspiral, but with no direct wave. [37]

The radiation reaction force can be calculated by Padé resummation of gravitational wave flux. A technique to establish the radiation is the Cauchy-characteristic extraction technique CCE, which gives a close estimate of the flux at infinity, without having to calculate at larger and larger finite distances.

The final mass of the resultant black hole depends on the definition of mass in general relativity. The Bondi mass MB is calculated from the Bondi–Sach mass-loss formula, , with f(U) being the gravitational wave flux at retarded time U. f is a surface integral of the news function at null infinity varied by solid angle. The Arnowitt–Deser–Misner (ADM) energy, or ADM mass, is the mass as measured at infinite distance and includes all the gravitational radiation emitted: .

Angular momentum is also lost in the gravitational radiation. This is primarily in the z axis of the initial orbit. It is calculated by integrating the product of the multipolar metric waveform with the news function complement over retarded time. [38]

Shape

One of the problems to solve is the shape or topology of the event horizon during a black-hole merger.

In numerical models, test geodesics are inserted to see whether they encounter an event horizon. As two black holes approach each other, a "duckbill" shape protrudes from each of the two event horizons towards the other one. This protrusion extends longer and narrower until it meets the protrusion from the other black hole. At this point in time the event horizon has a very narrow X-shape at the meeting point. The protrusions are drawn out into a thin thread. [39] The meeting point expands to a roughly cylindrical connection called a bridge. [39]

Simulations as of 2011 had not produced any event horizons with toroidal topology (ring-shaped). Some researchers suggested that it would be possible if, for example, several black holes in the same nearly circular orbit coalesce. [39]

Black-hole merger recoil

An unexpected result can occur with binary black holes that merge, in that the gravitational waves carry momentum, and the merging black-hole pair accelerates, seemingly violating Newton's third law. The center of gravity can add over 1000 km/s of kick velocity. [40] The greatest kick velocities (approaching 5000 km/s) occur for equal-mass and equal-spin-magnitude black-hole binaries, when the spins directions are optimally oriented to be counter-aligned, parallel to the orbital plane or nearly aligned with the orbital angular momentum. [41] This is enough to escape large galaxies. With more likely orientations, a smaller effect takes place, perhaps only a few hundred kilometers per second. This sort of speed can eject merging binary black holes from globular clusters, thus preventing the formation of massive black holes in globular-cluster cores. This, in turn, reduces the chances of subsequent mergers, and thus the chance of detecting gravitational waves. For non-spinning black holes a maximum recoil velocity of 175 km/s occurs for masses in the ratio of five to one. When spins are aligned in the orbital plane, a recoil of 5000 km/s is possible with two identical black holes. [42] Parameters that may be of interest include the point at which the black holes merge, the mass ratio that produces maximum kick, and how much mass/energy is radiated via gravitational waves. In a head-on collision this fraction is calculated at 0.002, or 0.2%. [43] One of the best candidates of the recoiled supermassive black holes is CXO J101527.2+625911. [44]

See also

Related Research Articles

<span class="mw-page-title-main">Black hole</span> Region that has a no-return boundary

A black hole is a region of spacetime wherein gravity is so strong that no matter or electromagnetic energy can escape it. Albert Einstein's theory of general relativity predicts that a sufficiently compact mass can deform spacetime to form a black hole. The boundary of no escape is called the event horizon. A black hole has a great effect on the fate and circumstances of an object crossing it, but it has no locally detectable features according to general relativity. In many ways, a black hole acts like an ideal black body, as it reflects no light. Quantum field theory in curved spacetime predicts that event horizons emit Hawking radiation, with the same spectrum as a black body of a temperature inversely proportional to its mass. This temperature is of the order of billionths of a kelvin for stellar black holes, making it essentially impossible to observe directly.

<span class="mw-page-title-main">Laser Interferometer Space Antenna</span> European space mission to measure gravitational waves

The Laser Interferometer Space Antenna (LISA) is a planned space probe to detect and accurately measure gravitational waves—tiny ripples in the fabric of spacetime—from astronomical sources. LISA will be the first dedicated space-based gravitational-wave observatory. It aims to measure gravitational waves directly by using laser interferometry. The LISA concept features three spacecraft arranged in an equilateral triangle with each side 2.5 million kilometers long, flying in an Earth-like heliocentric orbit. The distance between the satellites is precisely monitored to detect a passing gravitational wave.

<span class="mw-page-title-main">Intermediate-mass black hole</span> Class of black holes with a mass range of 100 to 100000 solar masses

An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range of one hundred to one hundred thousand (102–105) solar masses: significantly higher than stellar black holes but lower than the hundred thousand to more than one billion (105–109) solar mass supermassive black holes. Several IMBH candidate objects have been discovered in the Milky Way galaxy and others nearby, based on indirect gas cloud velocity and accretion disk spectra observations of various evidentiary strength.

Numerical relativity is one of the branches of general relativity that uses numerical methods and algorithms to solve and analyze problems. To this end, supercomputers are often employed to study black holes, gravitational waves, neutron stars and many other phenomena described by Albert Einstein's theory of general relativity. A currently active field of research in numerical relativity is the simulation of relativistic binaries and their associated gravitational waves.

<span class="mw-page-title-main">Gravitational wave background</span> Random background of gravitational waves permeating the Universe

The gravitational wave background is a random background of gravitational waves permeating the Universe, which is detectable by gravitational-wave experiments, like pulsar timing arrays. The signal may be intrinsically random, like from stochastic processes in the early Universe, or may be produced by an incoherent superposition of a large number of weak independent unresolved gravitational-wave sources, like supermassive black-hole binaries. Detecting the gravitational wave background can provide information that is inaccessible by any other means about astrophysical source population, like hypothetical ancient supermassive black-hole binaries, and early Universe processes, like hypothetical primordial inflation and cosmic strings.

<span class="mw-page-title-main">Gravitational wave</span> Aspect of relativity in physics

Gravitational waves are transient displacements in a gravitational field – generated by the relative motion of gravitating masses – that radiate outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as the gravitational equivalent of electromagnetic waves. In 1916, Albert Einstein demonstrated that gravitational waves result from his general theory of relativity as ripples in spacetime.

<span class="mw-page-title-main">Gravitational-wave astronomy</span> Branch of astronomy using gravitational waves

Gravitational-wave astronomy is a subfield of astronomy concerned with the detection and study of gravitational waves emitted by astrophysical sources.

<span class="mw-page-title-main">Alessandra Buonanno</span> Italian-American physicist

Alessandra Buonanno is an Italian-American theoretical physicist and director at the Max Planck Institute for Gravitational Physics in Potsdam. She is the head of the "Astrophysical and Cosmological Relativity" department. She holds a research professorship at the University of Maryland, College Park, and honorary professorships at the Humboldt University in Berlin, and the University of Potsdam. She is a leading member of the LIGO Scientific Collaboration, which observed gravitational waves from a binary black-hole merger in 2015.

A hypercompact stellar system (HCSS) is a dense cluster of stars around a supermassive black hole that has been ejected from the center of its host galaxy. Stars that are close to the black hole at the time of the ejection will remain bound to the black hole after it leaves the galaxy, forming the HCSS.

<span class="mw-page-title-main">Primordial black hole</span> Hypothetical black hole formed soon after the Big Bang

In cosmology, primordial black holes (PBHs) are hypothetical black holes that formed soon after the Big Bang. In the inflationary era and early radiation-dominated universe, extremely dense pockets of subatomic matter may have been tightly packed to the point of gravitational collapse, creating primordial black holes without the supernova compression typically needed to make black holes today. Because the creation of primordial black holes would pre-date the first stars, they are not limited to the narrow mass range of stellar black holes.

In astrophysics, the chirp mass of a compact binary system determines the leading-order orbital evolution of the system as a result of energy loss from emitting gravitational waves. Because the gravitational wave frequency is determined by orbital frequency, the chirp mass also determines the frequency evolution of the gravitational wave signal emitted during a binary's inspiral phase. In gravitational wave data analysis, it is easier to measure the chirp mass than the two component masses alone.

<span class="mw-page-title-main">Extreme mass ratio inspiral</span>

In astrophysics, an extreme mass ratio inspiral (EMRI) is the orbit of a relatively light object around a much heavier object, that gradually spirals in due to the emission of gravitational waves. Such systems are likely to be found in the centers of galaxies, where stellar mass compact objects, such as stellar black holes and neutron stars, may be found orbiting a supermassive black hole. In the case of a black hole in orbit around another black hole this is an extreme mass ratio binary black hole. The term EMRI is sometimes used as a shorthand to denote the emitted gravitational waveform as well as the orbit itself.

The TianQin Project is a proposed space-borne gravitational-wave observatory consisting of three spacecraft in Earth orbit. The TianQin project is being led by Professor Luo Jun, President of Sun Yat-sen University, and is based in the university's Zhuhai campus. Construction on project-related infrastructure, which will include a research building, ultra-quiet cave laboratory, and observation center, began in March 2016. The project is estimated to cost 15 billion RMB, with a projected completion date in the mid-2030s. In December 2019, China launched Tianqin-1, a technology demonstration.

<span class="mw-page-title-main">First observation of gravitational waves</span> Detection made by LIGO and Virgo interferometers (2015)

The first direct observation of gravitational waves was made on 14 September 2015 and was announced by the LIGO and Virgo collaborations on 11 February 2016. Previously, gravitational waves had been inferred only indirectly, via their effect on the timing of pulsars in binary star systems. The waveform, detected by both LIGO observatories, matched the predictions of general relativity for a gravitational wave emanating from the inward spiral and merger of two black holes and the subsequent ringdown of a single, 62 M☉ black hole remnant. The signal was named GW150914. It was also the first observation of a binary black hole merger, demonstrating both the existence of binary stellar-mass black hole systems and the fact that such mergers could occur within the current age of the universe.

Manuela Campanelli is a distinguished professor of astrophysics of the Rochester Institute of Technology. She also holds the John Vouros endowed professorship at RIT and is the director of its Center for Computational Relativity and Gravitation. Her work focuses on the astrophysics of merging black holes and neutron stars, which are powerful sources of gravitational waves, electromagnetic radiation and relativistic jets. This research is central to the fields of relativistic astrophysics and gravitational-wave astronomy.

<span class="mw-page-title-main">GW170104</span>

GW170104 was a gravitational wave signal detected by the LIGO observatory on 4 January 2017. On 1 June 2017, the LIGO and Virgo collaborations announced that they had reliably verified the signal, making it the third such signal announced, after GW150914 and GW151226, and fourth overall.

In gravitational wave astronomy, a golden binary is a binary black hole collision event whose inspiral and ringdown phases have been measured accurately enough to provide separate measurements of the initial and final black hole masses.

<span class="mw-page-title-main">GW190521</span> Gravitational wave observation

GW190521 was a gravitational wave signal resulting from the merger of two black holes. It was possibly associated with a coincident flash of light; if this association is correct, the merger would have occurred near a third supermassive black hole. The event was observed by the LIGO and Virgo detectors on 21 May 2019 at 03:02:29 UTC, and published on 2 September 2020. The event had a Luminosity distance of 17 billion light years away from Earth, within a 765 deg2 area towards Coma Berenices, Canes Venatici, or Phoenix.

Ground-based interferometric gravitational-wave search refers to the use of extremely large interferometers built on the ground to passively detect gravitational wave events from throughout the cosmos. Most recorded gravitational wave observations have been made using this technique; the first detection, revealing the merger of two black holes, was made in 2015 by the LIGO sites.

References

  1. ↑ Credits: SXS (Simulating eXtreme Spacetimes) project.
  2. 1 2 3 Pretorius, Frans (2005). "Evolution of Binary Black-Hole Spacetimes". Physical Review Letters. 95 (12): 121101. arXiv: gr-qc/0507014 . Bibcode:2005PhRvL..95l1101P. doi:10.1103/PhysRevLett.95.121101. ISSN   0031-9007. PMID   16197061. S2CID   24225193.
  3. 1 2 3 Campanelli, M.; Lousto, C. O.; Marronetti, P.; Zlochower, Y. (2006). "Accurate Evolutions of Orbiting Black-Hole Binaries without Excision". Physical Review Letters. 96 (11): 111101. arXiv: gr-qc/0511048 . Bibcode:2006PhRvL..96k1101C. doi:10.1103/PhysRevLett.96.111101. ISSN   0031-9007. PMID   16605808. S2CID   5954627.
  4. 1 2 3 Baker, John G.; Centrella, Joan; Choi, Dae-Il; Koppitz, Michael; van Meter, James (2006). "Gravitational-Wave Extraction from an Inspiraling Configuration of Merging Black Holes". Physical Review Letters. 96 (11): 111102. arXiv: gr-qc/0511103 . Bibcode:2006PhRvL..96k1102B. doi:10.1103/PhysRevLett.96.111102. ISSN   0031-9007. PMID   16605809. S2CID   23409406.
  5. ↑ Abadie, J.; Abbott, B. P.; Abbott, R.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Ajith, P.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; et al. (LIGO Scientific Collaboration and Virgo Collaboration) (2011-06-06). "Search for gravitational waves from binary black hole inspiral, merger, and ringdown". Physical Review D. 83 (12): 122005. arXiv: 1102.3781 . Bibcode: 2011PhRvD..83l2005A . doi:10.1103/PhysRevD.83.122005. ISSN   1550-7998. S2CID   174250.
  6. ↑ "Observation Of Gravitational Waves From A Binary Black Hole Merger" (PDF). LIGO. 11 February 2016. Archived from the original (PDF) on 16 February 2016. Retrieved 11 February 2016.
  7. ↑ Harwood, W. (11 February 2016). "Einstein was right: Scientists detect gravitational waves in breakthrough". CBS News . Archived from the original on 12 February 2016. Retrieved 12 February 2016.
  8. ↑ Drake, Nadia (11 February 2016). "Found! Gravitational Waves, or a Wrinkle in Spacetime". National Geographic News . Archived from the original on 12 February 2016. Retrieved 12 February 2016.
  9. ↑ Liu, Fukun; Komossa, Stefanie; Schartel, Norbert (22 April 2014). "Unique Pair of Hidden Black Holes Discovered yy XMM-Newton". A milli-parsec supermassive black hole binary candidate in the galaxy SDSS J120136.02+300305.5. Retrieved 23 December 2014.
  10. 1 2 3 Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; et al. (LIGO Scientific Collaboration and Virgo Collaboration) (2016-02-11). "Observation of Gravitational Waves from a Binary Black Hole Merger". Physical Review Letters. 116 (6): 061102. arXiv: 1602.03837 . Bibcode:2016PhRvL.116f1102A. doi:10.1103/PhysRevLett.116.061102. ISSN   0031-9007. PMID   26918975. S2CID   124959784.{{cite journal}}: CS1 maint: date and year (link)
  11. ↑ "NASA Visualization Probes the Doubly Warped World of Binary Black Holes". NASA. 15 April 2021. Retrieved 16 April 2021.
  12. ↑ Komossa, S.; Burwitz, V.; Hasinger, G.; Predehl, P.; Kaastra, J. S.; Ikebe, Y. (2003-01-01). "Discovery of a Binary Active Galactic Nucleus in the Ultraluminous Infrared Galaxy NGC 6240 Using Chandra". The Astrophysical Journal. 582 (1). The American Astronomical Society: L15–L19. arXiv: astro-ph/0212099 . Bibcode:2003ApJ...582L..15K. doi:10.1086/346145. ISSN   0004-637X. S2CID   16697327.
  13. ↑ Zhou, Hongyan; Wang, Tinggui; Zhang, Xueguang; Dong, Xiaobo; Li, Cheng (2004-03-20). "Obscured Binary Quasar Cores in SDSS J104807.74+005543.5?". The Astrophysical Journal. 604 (1). The American Astronomical Society: L33–L36. arXiv: astro-ph/0411167 . Bibcode:2004ApJ...604L..33Z. doi:10.1086/383310. ISSN   0004-637X. S2CID   14297940.
  14. ↑ Gerke, Brian F.; Newman, Jeffrey A.; Lotz, Jennifer; Yan, Renbin; Barmby, P.; Coil, Alison L.; Conselice, Christopher J.; Ivison, R. J.; Lin, Lihwai; Koo, David C.; Nandra, Kirpal; Salim, Samir; Small, Todd; Weiner, Benjamin J.; Cooper, Michael C.; Davis, Marc; Faber, S. M.; Guhathakurta, Puragra; et al. (6 April 2007). "The DEEP2 Galaxy Redshift Survey: AEGIS Observations of a Dual AGN at z = 0.7". The Astrophysical Journal Letters. 660 (1): L23–L26. arXiv: astro-ph/0608380 . Bibcode:2007ApJ...660L..23G. doi:10.1086/517968. S2CID   14320681.
  15. ↑ Valtonen, M. J.; Mikkola, S.; Merritt, D.; Gopakumar, A.; Lehto, H. J.; Hyvönen, T.; Rampadarath, H.; Saunders, R.; Basta, M.; Hudec, R. (2010-02-01). "Measuring the Spin of the Primary Black Hole in OJ287". The Astrophysical Journal. 709 (2): 725–732. arXiv: 0912.1209 . Bibcode:2010ApJ...709..725V. doi:10.1088/0004-637X/709/2/725. ISSN   0004-637X. S2CID   119276181.
  16. ↑ Pesce, D. W.; Seth, A. C.; Greene, J. E.; Braatz, J. A.; Condon, J. J.; Kent, B. R.; Krajnović, D. (March 2021). "A Restless Supermassive Black Hole in the Galaxy J0437+2456". Astrophysical Journal. 909 (2): 141–153. arXiv: 2101.07932 . Bibcode:2021ApJ...909..141P. doi: 10.3847/1538-4357/abde3d . S2CID   231648121.
  17. ↑ Graham, Matthew J.; Djorgovski, S. G.; Stern, Daniel; Glikman, Eilat; Drake, Andrew J.; Mahabal, Ashish A.; Donalek, Ciro; Larson, Steve; Christensen, Eric (7 January 2015). "A possible close supermassive black-hole binary in a quasar with optical periodicity". Nature. 518 (7537): 74–6. arXiv: 1501.01375 . Bibcode:2015Natur.518...74G. doi:10.1038/nature14143. ISSN   0028-0836. PMID   25561176. S2CID   4459433.
  18. ↑ D'Orazio, Daniel J.; Haiman, Zoltán; Schiminovich, David (17 September 2015). "Relativistic boost as the cause of periodicity in a massive black-hole binary candidate". Nature. 525 (7569): 351–353. arXiv: 1509.04301 . Bibcode:2015Natur.525..351D. doi:10.1038/nature15262. PMID   26381982. S2CID   205245606.
  19. ↑ Overbye, Dennis (16 September 2015). "More Evidence for Coming Black Hole Collision". The New York Times.
  20. ↑ Milosavljević, Miloš; Merritt, David (October 2003). "The Final Parsec Problem" (PDF). AIP Conference Proceedings. 686 (1). American Institute of Physics: 201–210. arXiv: astro-ph/0212270 . Bibcode:2003AIPC..686..201M. doi:10.1063/1.1629432. S2CID   12124842.
  21. ↑ Merritt, David (2013). Dynamics and Evolution of Galactic Nuclei. Princeton: Princeton University Press. ISBN   978-0-691-12101-7.
  22. ↑ Lamb, William (8 August 2024). "Don't Be So Cold – Self-Interacting Dark Matter as a Solution to the 'Final Parsec Problem'". Astrobites.
  23. ↑ Alonso-Álvarez, Gonzalo; Cline, James M.; Dewar, Caitlyn (9 July 2024). "Self-Interacting Dark Matter Solves the Final Parsec Problem of Supermassive Black Hole Mergers". Physical Review Letters . 133 (2) 021401. arXiv: 2401.14450 . Bibcode:2024PhRvL.133b1401A. doi: 10.1103/PhysRevLett.133.021401 . PMID   39073950. For collisionless cold DM, the friction deposits so much energy that the spike is disrupted and cannot bridge the final parsec, while for self-interacting DM, the isothermal core of the halo can act as a reservoir for the energy liberated from the SMBH orbits.
  24. ↑ Ryu, Taeho; Perna, Rosalba; Haiman, Zoltán; Ostriker, Jeremiah P.; Stone, Nicholas C. (2018). "Interactions between multiple supermassive black holes in galactic nuclei: a solution to the final parsec problem". Monthly Notices of the Royal Astronomical Society. 473 (3): 3410–3433. arXiv: 1709.06501 . Bibcode:2018MNRAS.473.3410R. doi: 10.1093/mnras/stx2524 . S2CID   119083047.
  25. ↑ Iwasawa, Masaki; Funato, Yoko; Makino, Junichiro (2006). "Evolution of Massive Blackhole Triples I – Equal-mass binary–single systems". Astrophys. J. 651 (2): 1059–1067. arXiv: astro-ph/0511391 . Bibcode:2006ApJ...651.1059I. doi:10.1086/507473. S2CID   14816623. We found that in most cases two of the three BHs merge through gravitational wave (GW) radiation in the timescale much shorter than the Hubble time, before ejecting one BH through a slingshot.
  26. ↑ "Introduction to LIGO & Gravitational Waves: Inspiral Gravitational Waves". LIGO Scientific Collaboration.
  27. 1 2 Ori, Amos; Thorne, Kip S. (28 November 2000). "Transition from inspiral to plunge for a compact body in a circular equatorial orbit around a massive, spinning black hole". Physical Review D. 62 (12): 124022. arXiv: gr-qc/0003032 . Bibcode:2000PhRvD..62l4022O. doi:10.1103/PhysRevD.62.124022.
  28. ↑ "For whom the black hole rings". www.aei.mpg.de.
  29. ↑ Capano, Collin D.; Cabero, Miriam; Westerweck, Julian; Abedi, Jahed; Kastha, Shilpa; Nitz, Alexander H.; Wang, Yi-Fan; Nielsen, Alex B.; Krishnan, Badri (28 November 2023). "Multimode Quasinormal Spectrum from a Perturbed Black Hole". Physical Review Letters. 131 (22): 221402. arXiv: 2105.05238 . Bibcode:2023PhRvL.131v1402C. doi:10.1103/PhysRevLett.131.221402. PMID   38101361.
  30. 1 2 Castelvecchi, Davide; Witze, Witze (February 11, 2016). "Einstein's gravitational waves found at last". Nature News. doi:10.1038/nature.2016.19361. S2CID   182916902 . Retrieved 2016-02-11.
  31. ↑ "Gravitational waves detected 100 years after Einstein's prediction". www.nsf.gov. NSF – National Science Foundation. Retrieved 2016-02-11.
  32. ↑ Abbott, Benjamin P.; et al. (LIGO Scientific Collaboration and Virgo Collaboration) (11 February 2016). "Properties of the binary black hole merger GW150914". Physical Review Letters. 116 (24): 241102. arXiv: 1602.03840 . Bibcode:2016PhRvL.116x1102A. doi:10.1103/PhysRevLett.116.241102. PMID   27367378. S2CID   217406416.
  33. ↑ Kramer, Sarah (11 February 2016). "This collision was 50 times more powerful than all the stars in the universe combined". Tech Insider. Retrieved 12 February 2016.
  34. ↑ Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; et al. (The LIGO Scientific Collaboration and The Virgo Collaboration) (2016-10-21). "Improved Analysis of GW150914 Using a Fully Spin-Precessing Waveform Model". Physical Review X. 6 (4): 041014. arXiv: 1606.01210 . Bibcode:2016PhRvX...6d1014A. doi:10.1103/PhysRevX.6.041014. ISSN   2160-3308. S2CID   18217435.{{cite journal}}: CS1 maint: date and year (link)
  35. ↑ Hahn, Susan G.; Lindquist, Richard W. (1964). "The two-body problem in geometrodynamics". Annals of Physics. 29 (2): 304–331. Bibcode:1964AnPhy..29..304H. doi:10.1016/0003-4916(64)90223-4. ISSN   0003-4916.
  36. ↑ Smarr, Larry; Čadež, Andrej; DeWitt, Bryce; Eppley, Kenneth (1976). "Collision of two black holes: Theoretical framework". Physical Review D. 14 (10): 2443–2452. Bibcode:1976PhRvD..14.2443S. doi:10.1103/PhysRevD.14.2443. ISSN   0556-2821.
  37. 1 2 3 Nichols, David A.; Chen, Yanbei (2012). "Hybrid method for understanding black-hole mergers: Inspiralling case". Physical Review D. 85 (4): 044035. arXiv: 1109.0081 . Bibcode:2012PhRvD..85d4035N. doi:10.1103/PhysRevD.85.044035. ISSN   1550-7998. S2CID   30890236.
  38. ↑ Damour, Thibault; Nagar, Alessandro; Pollney, Denis; Reisswig, Christian (2012). "Energy Versus Angular Momentum in Black Hole Binaries". Physical Review Letters. 108 (13): 131101. arXiv: 1110.2938 . Bibcode:2012PhRvL.108m1101D. doi: 10.1103/PhysRevLett.108.131101 . ISSN   0031-9007. PMID   22540688.
  39. 1 2 3 Cohen, Michael I.; Kaplan, Jeffrey D.; Scheel, Mark A. (2012). "Toroidal horizons in binary black hole inspirals". Physical Review D. 85 (2): 024031. arXiv: 1110.1668 . Bibcode:2012PhRvD..85b4031C. doi:10.1103/PhysRevD.85.024031. ISSN   1550-7998. S2CID   37654897.
  40. ↑ Pietilä, Harri; Heinämäki, Pekka; Mikkola, Seppo; Valtonen, Mauri J. (10 January 1996). Anisotropic Gravitational Radiation In The Merger Of Black Holes. Relativistic Astrophysics Conference. CiteSeerX   10.1.1.51.2616 .
  41. ↑ Campanelli, Manuela; Lousto, Carlos; Zlochower, Yosef; Merritt, David (7 June 2007). "Maximum Gravitational Recoil". Physical Review Letters. 98 (23): 231102. arXiv: gr-qc/0702133 . Bibcode:2007PhRvL..98w1102C. doi:10.1103/PhysRevLett.98.231102. PMID   17677894. S2CID   29246347.
  42. ↑ Lousto, Carlos; Zlochower, Yosef (2011). "Hangup Kicks: Still Larger Recoils by Partial Spin–Orbit Alignment of Black-Hole Binaries". Physical Review Letters. 107 (23): 231102. arXiv: 1108.2009 . Bibcode:2011PhRvL.107w1102L. doi:10.1103/PhysRevLett.107.231102. PMID   22182078. S2CID   15546595.
  43. ↑ Pietilä, Harri; Heinämäki, Pekka; Mikkola, Seppo; Valtonen, Mauri J. (1995). "Anisotropic gravitational radiation in the problems of three and four black holes". Celestial Mechanics and Dynamical Astronomy . 62 (4): 377–394. Bibcode:1995CeMDA..62..377P. CiteSeerX   10.1.1.51.2616 . doi:10.1007/BF00692287. S2CID   122956625.
  44. ↑ Kim, D.-C.; et al. (2017). "A Potential Recoiling Supermassive Black Hole CXO J101527.2+625911". Astrophysical Journal . 840 (2): 71–77. arXiv: 1704.05549 . Bibcode:2017ApJ...840...71K. doi: 10.3847/1538-4357/aa6030 . S2CID   119401892.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.