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List Of Fastest Rotating Black Holes
Below is a list of fastest rotating black holes measured in the dimensionless rotational parameter ''a''. Methodologies for spin measurements Accreting black hole spins can be measured by observing the X-ray spectrum of the black hole and identifying spectral features caused by certain characteristics of the accretion disc. This can be used to determine the innermost stable circular orbit and hence the spin. Another method measures the radiative efficiency of the accretion disc. List Prograde rotation See also * List of most massive black holes * Orders of magnitude (speed) To help compare different orders of magnitude, the following list describes various speed levels between approximately 2.2 m/s and 3.0 m/s (the speed of light). Values in bold are exact. List of orders of magnitude for speed See als ... References {{reflist, refs= {{Cite journal, last=Reynolds, first=Christopher S., date=29 November 2013, title=The spin of supermassive black holes, journ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerr
Kerr may refer to: People *Kerr (surname) *Kerr (given name) Places ;United States *Kerr Township, Champaign County, Illinois *Kerr, Montana, A US census-designated place *Kerr, Ohio, an unincorporated community *Kerr County, Texas Kerr County is a county located on the Edwards Plateau in the U.S. state of Texas. As of the 2020 census, its population was 52,598. Its county seat is Kerrville. The county was named by Joshua D. Brown for his fellow Kentucky native, Jam ... Other uses * KERR, A US radio station *Kerr, a brand of food Mason jars and lids * Clan Kerr, a Scottish clan See also * * * Ker (other) {{Disambiguation, geo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accretion Disc
An accretion disk is a structure (often a circumstellar disk) formed by diffuse material in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward the central body. Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. The frequency range of that radiation depends on the central object's mass. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum. The study of oscillation modes in accretion disks is referred to as diskoseismology. Manifestations Accretion disks are a ubiquitous phenomenon in astrophysics; active galactic nuclei, protoplanetary disks, and gamma ray bursts all involve accretion disks. These disks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Innermost Stable Circular Orbit
The innermost stable circular orbit (often called the ISCO) is the smallest marginally stable circular orbit in which a test particle can stably orbit a massive object in general relativity. The location of the ISCO, the ISCO-radius (r_), depends on the mass and angular momentum (spin) of the central object. The ISCO plays an important role in black hole accretion disks since it marks the inner edge of the disk. The ISCO should not be confused with the Roche limit, the innermost point where a physical object can orbit before tidal forces break it up. The ISCO is concerned with theoretical ''test particle''s, not real objects. In general terms, the ISCO will be far closer to the central object than the Roche limit. Basic concept In classical mechanics, an orbit is achieved when a test particle's angular momentum is enough to resist the gravity force of the central object. As the test particle approaches the central object, the required amount of angular momentum grows, due to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supermassive Black Hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun (). Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, including light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. For example, the Milky Way galaxy has a supermassive black hole at its center, corresponding to the radio source Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering active galactic nuclei (AGNs) and quasars. Two supermassive black holes have been directly imaged by the Event Horizon Telescope: the black hole in the giant elliptical galaxy Messier 87 and the black hole at the Milky Way's center (Sagittarius A*). Descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GRS 1915+105
GRS 1915+105 or V1487 Aquilae is an X-ray binary star system containing a main sequence star and a black hole. Transfer of material from the star to the black hole generates a relativistic jet, making this a microquasar system. The jet exhibits apparent superluminal motion. It was discovered on August 15, 1992 by the WATCH all-sky monitor aboard Granat. "GRS" stands for "GRANAT source", "1915" is the right ascension (19 hours and 15 minutes) and "105" reflects the approximate declination (10 degrees and 56 arcminutes). The near-infrared counterpart was determined by spectroscopic observations. The binary system lies 11,000 parsecs away in Aquila. The black hole in GRS 1915+105 is 10 to 18 solar masses. The black hole rotates at least 950 times per second, giving it a spin parameter >0.82 (1.0 is the theoretical maximum). Galactic superluminal source In 1994, GRS 1915+105 became the first known galactic source that ejects material with apparent superluminal motion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GX 339-4
GX 339-4 is a moderately strong variable galactic X-ray binary#Low-mass X-ray binary, low-mass X-ray binary (LMXB) source and black hole candidate that flares from time to time. From spectroscopic measurements, the mass of the black-hole was found to be at least of 5.8 solar masses. Thomas Henry Markert ''et al.'' discovered GX 339-4 in 1973, in data obtained by the Massachusetts Institute of Technology, MIT Cosmic Ray Experiment on OSO-7. An optical counterpoint to the X-ray source was found by Jonathan E. Grindlay in 1979, and it is optically variable star, variable. For that reason it was given a variable star designation, V821 Arae, in 1981. During the outbursts GX 339-4 shows evolution of quasi-periodic oscillations (QPOs). In the rising phase the QPO frequency monotonically increase as the CENBOL propagates closer to the black hole and in the declining phase the QPO frequency monotonically decreases since the CENBOL recedes away from the black hole after viscosity is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IGR J17091-3624
IGR J17091-3624 (also IGR J17091) is a stellar mass black hole 28,000 light-years away. It lies in the constellation Scorpius in the Milky Way galaxy. Discovery IGR J17091 was discovered by ESA's INTEGRAL satellite in April 2003. Description IGR J17091 is a stellar mass black hole with a mass between 3 and 10 . It is a binary system in which a star orbits the black hole. Its small size may make it a candidate for the smallest black hole discovered. However, as of 2017 its mass was described as "unknown". Observations by the Chandra X-ray Observatory in 2011 discovered that it produces the fastest winds ever coming from an accretion disk at 3,218,688 km/h (20 million mph) making it about 3% of the speed of light. This is 10 times faster than the next-highest-measured wind speed. According to Ashley King from the University of Michigan "Contrary to the popular perception of black holes pulling in all of the material that gets close, we estimate up to 95 percent of the ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cygnus X-1
Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus and was the first such source widely accepted to be a black hole. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources detectable from Earth, producing a peak X-ray flux density of (). It remains among the most studied astronomical objects in its class. The compact object is now estimated to have a mass about 21.2 times the mass of the Sun and has been shown to be too small to be any known kind of normal star or other likely object besides a black hole. If so, the radius of its event horizon has "as upper bound to the linear dimension of the source region" of occasional X-ray bursts lasting only for about 1 ms. Cygnus X-1 belongs to a high-mass X-ray binary system, located about 7,000 light-years away, that includes a blue supergiant variable star designated HDE 226868, which it orbits at about 0.2 AU, or 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
V404 Cygni
V404 Cygni is a microquasar and a triple star system in the constellation of Cygnus. It contains a black hole with a mass of about and an early K giant star companion with a mass slightly smaller than the Sun, and an evolved tertiary component. The inner star and the black hole orbit each other every 6.47129 days at fairly close range, while the outer tertiary takes 70000 years to orbit the inner binary system. Due to their proximity and the intense gravity of the black hole, the secondary star loses mass to an accretion disk around the black hole and ultimately to the black hole itself. The "V" in the name indicates that it is a variable star, which repeatedly gets brighter and fainter over time. It is also considered a nova, because at least three times in the 20th century it produced a bright outburst of energy. Finally, it is a soft X-ray transient because it periodically emits short bursts of X-rays. The black hole companion has been proposed as a Q star ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Most Massive Black Holes
This is an ordered list of the most massive black holes so far discovered (and probable candidates), measured in units of solar masses (), approximately . Introduction A supermassive black hole (SMBH) is an extremely large black hole, on the order of hundreds of thousands to tens of billions of solar masses (), and is theorized to exist in the center of almost all massive galaxies. In some galaxies, there are even binary systems of supermassive black holes (see the OJ 287 system.) Unambiguous dynamical evidence for SMBHs exists only in a handful of galaxies; these include the Milky Way, the Local Group galaxies M31 and M32, and a few galaxies beyond the Local Group, e.g. NGC 4395. In these galaxies, the mean square (or root mean square) velocities of the stars or gas rises as ~1/r near the center, indicating a central point mass. In all other galaxies observed to date, the rms velocities are flat, or even falling, toward the center, making it impossible to state with cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orders Of Magnitude (speed) ...
To help compare different orders of magnitude, the following list describes various speed levels between approximately 2.2 m/s and 3.0 m/s (the speed of light). Values in bold are exact. List of orders of magnitude for speed See also * Typical projectile speeds - also showing the corresponding kinetic energy per unit mass * Neutron temperature References {{Orders of magnitude Units of velocity Physical quantities Speed In kinematics, the speed (commonly referred to as ''v'') of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit of time; it is thus a non-negative scalar quantity. Intro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
