OJ 287 is a
BL Lac objectA BL Lacertae object or BL Lac object is a type of active galaxy with an active galactic nucleus and is named after its prototype, BL Lacertae. In contrast to other types of active galactic nuclei, BL Lacs are characterized by rapid and large amplitude flux variability and significant optical...
that has produced quasi-periodic optical outbursts going back approximately 100 years, as first apparent on photographic plates from 1891. It was first detected at radio wavelengths during the course of the
Ohio Sky SurveyThe Ohio Sky Survey was an astronomical survey of extragalactic radio sources. Data were taken between 1965 and 1971 using the Big Ear radio telescope at the Ohio State University Radio Observatory , also known as the "Big Ear Radio Observatory "....
.
Its central
supermassive black holeA supermassive black hole is a black hole with the highest classification of mass, on the order of hundreds of thousands to billions of solar masses...
is claimed to be the largest known, with a mass of 18 billion solar masses, more than six times the value calculated for the previous largest object.
The optical light curve shows that OJ 287 has a periodic variation of 11-12 years with a narrow double peak at maximum brightness.
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OJ 287 is a
BL Lac objectA BL Lacertae object or BL Lac object is a type of active galaxy with an active galactic nucleus and is named after its prototype, BL Lacertae. In contrast to other types of active galactic nuclei, BL Lacs are characterized by rapid and large amplitude flux variability and significant optical...
that has produced quasi-periodic optical outbursts going back approximately 100 years, as first apparent on photographic plates from 1891. It was first detected at radio wavelengths during the course of the
Ohio Sky SurveyThe Ohio Sky Survey was an astronomical survey of extragalactic radio sources. Data were taken between 1965 and 1971 using the Big Ear radio telescope at the Ohio State University Radio Observatory , also known as the "Big Ear Radio Observatory "....
.
Its central
supermassive black holeA supermassive black hole is a black hole with the highest classification of mass, on the order of hundreds of thousands to billions of solar masses...
is claimed to be the largest known, with a mass of 18 billion solar masses, more than six times the value calculated for the previous largest object.
The optical light curve shows that OJ 287 has a periodic variation of 11-12 years with a narrow double peak at maximum brightness. This kind of variation suggests that an engine is a binary
supermassive black holeA supermassive black hole is a black hole with the highest classification of mass, on the order of hundreds of thousands to billions of solar masses...
where a smaller black hole with a mass of only 100 million M
Sun orbits the larger one with an observed 11-12 year orbital period. The maximum brightness is obtained when the minor component moves through the accretion disk of the supermassive component at perinigricon.
The mass was calculated by a team led by
Mauri ValtonenMauri Valtonen is a Finnish astronomer and professor at the University of Turku. His fields of scientific interest include active galaxies, cosmology, and the three-body problem.Valtonen completed a Ph.D. from Cambridge University in 1975...
of
Tuorla ObservatoryTuorla Observatory is the Department of Astronomy at the University of Turku, southwest Finland. Currently it is the largest astronomical research institute in Finland...
in Finland, and the group's results were presented to the public at the 211th meeting of the
American Astronomical SocietyThe American Astronomical Society is a US society of professional astronomers and other interested individuals, headquartered in Washington, DC. The basic objective of the AAS is to promote the advancement of astronomy and closely related branches of science...
(AAS). The timing of these outbursts allows the
precessionPrecession refers to a change in the orientation of the rotation axis of a rotating body. It can be defined as a change in direction of the rotation axis in which the second Euler angle is constant...
of the companion's elliptical orbit to be measured (39° per orbit), which allows the mass of the central black hole to be calculated using
Albert EinsteinAlbert Einstein was a theoretical physicist. His many contributions to physics include the special and general theories of relativity, the founding of relativistic cosmology, the first post-Newtonian expansion, explaining the perihelion advance of Mercury, prediction of the deflection of...
's principles of
General relativityGeneral relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics. It unifies special relativity and Newton's law of universal gravitation, and describes gravity as a...
(see
Kepler problem in general relativityThe Kepler problem in general relativity involves solving for the motion of two spherical bodies interacting with one another by gravitation, as described by the theory of general relativity....
).
The accuracy of this measurement has been called into question due to the limited number and precision of observed companion orbits, but the calculated value will be further refined using future measurements. The companion's orbit is decaying via the emission of gravitational radiation and it is expected to merge with the central black hole within approximately 10,000 years.
The study has been published in the
Astrophysical JournalThe Astrophysical Journal is a scientific journal covering astronomy and astrophysics. It was founded in 1895 by the American astronomers George Ellery Hale and James E. Keeler...
.
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