A supermassive black hole ( SMBH or SBH ) is the largest black hole type, in the order of hundreds of thousands to billions of solar masses ( M ? ), and is found in the center of almost all massive galaxies known today. In the case of the Milky Way, the SMBH corresponds to the location of Sagittarius A *.
Video Supermassive black hole
Description
Supermassive black holes have properties that distinguish them from low mass classifications. First, the average density of the SMBH (defined as the mass of the black hole divided by the volume in its Schwarzschild radius) can be less than the water density in the case of some SMBHs. This is because the Schwarzschild radius is directly proportional to the mass, whereas the density is inversely proportional to the volume. Since the volume of spherical objects (such as the event horizon of a non-rotating black hole) is directly proportional to the radius of the radius, the black hole's density is inversely proportional to the square of the mass, and thus higher. the mass black hole has a lower average density. In addition, tidal forces around the event horizon are significantly weaker for large black holes. Like density, the tidal force on the body on the event horizon is inversely proportional to the square of the mass: a person on the surface of the Earth and one on the event's horizon of 10 million M ? black holes experience the same pairs of style between their head and legs. Unlike the star black mass hole, one will not experience significant tidal forces up very far into the black hole.
Maps Supermassive black hole
History of research
Donald Lynden-Bell and Martin Rees hypothesized in 1971 that the center of the Milky Way galaxy would contain supermassive black holes. Sagittarius A * was discovered and named on 13 and 15 February 1974, by astronomers Bruce Balick and Robert Brown using the basic interferometer from the National Radio Astronomy Observatory. They found a radio source emitting synchrotron radiation; it is found to be solid and immobile because of its gravity. Therefore, this is the first indication that supermassive black holes are at the center of the Milky Way.
Formation
The origin of supermassive black holes remains an open field of research. Astrophysicists agree that once a black hole is at the center of the galaxy, it can grow with increasing material and by joining with other black holes. Nevertheless, several hypotheses for the forming mechanism and the initial mass of the ancestors, or "seeds," of supermassive black holes.
One hypothesis is that the seeds are black holes of tens or perhaps hundreds of solar masses left behind by the explosions of large stars and grow with increasing material. Another model hypothesized that before the first stars, large gas clouds could collapse into "quasi-stars", which in turn would collapse into black holes about 20Ã, M ? . The "quasi star" becomes unstable against the radial disturbance due to the production of electron-positron pairs in essence and can collapse directly into the black hole without a supernova explosion (which will expend most of its mass, preventing black holes from growing as fast). Given enough mass nearby, black holes can be familiar to medium-mass black holes and possibly SMBH if the rate of increase persists.
Another model involves dense star clusters that are core collapsed because the negative heat capacity of the system drives the dispersion speed in the core to the relativistic speed. Finally, primordial black holes can be produced directly from external pressure in the first moments after the Big Bang. This primordial black hole will have more time than the above model to familiarize, enabling them sufficient time to reach supermassive size. The formation of black holes from the death of the first stars has been studied extensively and corroborated by observations. Other models for the black hole formation listed above are theoretical.
The difficulty in forming a supermassive black hole lies in the need for sufficient material to become a fairly small volume. This needs to have very little angular momentum for this to happen. Typically, the incremental process involves transporting a large initial endowment of angular outward momentum, and this appears to be a limiting factor in the growth of black holes. This is a major component of disk accretion theory. Gas accretion is the most efficient and also the most noticeable way in which black holes grow. The majority of the massive growth of supermassive black holes allegedly occurs through episodes of rapid gas accretion, which can be observed as active galactic nuclei or quasars. Observations reveal that quasars are much more frequent when the universe is younger, suggesting that supermassive black holes form and grow earlier. The main inhibiting factor for the theory of supermassive black hole formation is the observation of distant light quasars, which show that supermassive black holes of billions of solar masses have formed when the universe was less than a billion years old. This suggests that supermassive black holes appear very early in the universe, in the first massive galaxies.
The void exists in the mass distribution of the observed black hole. The black hole laying from a dead star has a mass of 5-80Ã, M ? . The minimum supermassive black hole is about one hundred thousand solar masses. The mass scale between these ranges is dubbed the black hole between-mass. Such a gap suggests a different formation process. However, some models suggest that ultraluminous X-ray sources (ULXs) may be the black holes of this missing group.
Nevertheless, there is an upper limit on how big supermassive black holes can grow. The so-called ultrabinal black holes (UMBHs), which are at least ten times the size of supermassive black holes, appear to have a theoretical upper limit of about 50 billion solar masses, because anything above this slows down growth to crawl starting about 10 billion solar masses) and causing an unstable accretion disk to surround a black hole to merge into an orbiting star.
A small minority of sources argue that the large supermassive black holes that are large in size are difficult to explain so quickly after the Big Bang, like ULAS J1342 0928, perhaps proof that our universe is the result of Big Bounce, instead of the Big Bang, with this supermassive black hole formed before Big Bounce.
Doppler Measurement
Some of the best evidence for the existence of a black hole is provided by the Doppler effect where the light from the nearby orbiting material shifts red when it recedes and shifts blue as it progresses. For material very close to the black hole, the orbital velocity should be proportional to the speed of light, so that the tidal material will appear very pale compared with the advanced material, which means that systems with symmetrical disks and symmetrical rings will obtain a very asymmetric visual appearance. This effect has been allowed for in modern computer-generated images like the examples presented here, based on a reasonable model for supermassive black holes in Sgr A * at the center of our own galaxy. But the resolution provided by the currently available telescope technology is not enough to confirm these predictions directly.
What has been observed directly in many systems is a lower non-relativistic velocity of matter orbiting further than what is considered a black hole. The direct Doppler size of the water maser that surrounds the nearby galactic core has revealed a very fast Keplerian movement, only possible with high concentrations of matter at the center. Currently, the only known object that can pack enough material in such a small space is a black hole, or things that will evolve into a black hole in a short time of astrophysics. For further active galaxies, broad-band width lines can be used to investigate gas orbiting near the event horizon. The echo mapping technique uses variability of these lines to measure mass and may spin from a black hole that moves the active galaxy.
The gravity of supermassive black holes in the center of many galaxies is considered to be active power objects such as Seyfert galaxies and quasars.
Korelasi empiris antara ukuran lubang hitam supermasif dan dispersi kecepatan bintang dari tonjolan galaksi disebut hubungan M-sigma.
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Astronomers are convinced that the Milky Way galaxy has a supermassive black hole at its center, 26,000 light-years from the Solar System, in a region called Sagitarius A * because:
- The star of S2 follows an elliptical orbit with a period of 15.2 years and a pericenter (shortest distance) 17 hours of light ( 1,8 ÃÆ' - 10 13 Ã, m or 120 AU) from the center of the center object.
- From the motion of a star S2, the mass of an object can be estimated as 4.1 million M ? , or about 8.2 ÃÆ' - 10 36 Ã, kg .
- The radius of a central object must be less than 17 hours of light, because otherwise the S2 will clash with it. In fact, recent observations of the S14 star show that the radius is no more than 6.25 light hours, about the diameter of Uranus's orbit.
- No known astronomical object other than a black hole can contain 4.1 million M ? in the volume of this space.
The Max Planck Institute for Extraterrestrial Physics and the UCLA Galactic Center Group have provided the strongest evidence to date that Sagittarius A * is the site of a supermassive black hole, based on data from the ESO Very Large Telescope and Keck telescope.
On January 5, 2015, NASA reported seeing the X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A *. Unusual events may be caused by a rupture of an asteroid that falls into a black hole or by winding a magnetic field line in a gas that flows into Sagitarius A *, according to astronomers.
Outside Milky Way
Unambiguous dynamic evidence for supermassive black holes exists only in some galaxies; these include the Milky Way, the local Group M31 and M32 galaxies, and some galaxies outside of the Local Groups, e.g. NGC 4395. In these galaxies, the average velocity (or rms) of stars or gas rises proportionally to 1/x var style = "padding-right: 1px;"> r near the center, indicating the center mass point. In all other galaxies observed to date, the rms velocity is flat, or even falling, toward the center, making it impossible to state with certainty that supermassive black holes are present. Nevertheless, it is generally accepted that the center of almost every galaxy contains supermassive black holes. The reason for this assumption is the M-sigma relationship, the tight relationship (low spread) between the mass of holes in 10 or more galaxies with safe detection, and the dispersion of the velocity of the stars in the bulge of the galaxies. This correlation, though only based on a handful of galaxies, shows many astronomers a strong relationship between the formation of the black hole and the galaxy itself.
The nearby Andromeda galaxy, 2.5 million light-years away, contains (1.1- 2.3) ÃÆ' - 10 8 (110-230 million) Ã, M ? central black hole, much larger than the Milky Way. The largest supermassive black hole around Milky Way seems to be M87, with a mass of (6,4 Â ± 0.5) ÃÆ' - 10 9 (about 6.4 billion) M ? at a distance of 53.5 million light years. On December 5, 2011, astronomers discovered the largest supermassive black hole in the nearest undiscovered universe, the ergonomic galaxy NGC 4889, with a mass of 2.1 ÃÆ' - 10 10 (21 billion) Ã, M ? at a distance of 336 million light-years away in the constellation Coma Berenices. The black hole in the quasar is far, very bright much bigger. Quasar hyperluminous APM 08279 5255 has a supermassive black hole with mass 2.3 ÃÆ' - 10 10 (23 billion) Ã, M ? . The larger one is still in another hyperluminous quasar S5 0014 81, one of the largest supermassive black holes ever found, which has a mass of 4.0 ÃÆ' - 10 10 (40 billion) Ã, M ? , or 10,000 times the size of a black hole in the Milky Way Galaxy. Both quasars are 12.1 billion light-years away.
The most massive black hole ever found, TON 618, weighs in 6.6 ÃÆ' - 10 10 (66 billion) Ã, M ? . It lies 10.4 billion light years away from us.
Some galaxies, such as the 4C 37.11 galaxy, appear to have two supermassive black holes in their centers, forming a binary system. If they collide, the event will create a strong gravitational wave. The binary supermassive black hole is believed to be a common consequence of galactic mergers. The binary pairings in OJ 287, 3.5 billion light-years, contain the most massive black holes in a pair, with an estimated mass of 18 billion M ? . A supermassive black hole was recently discovered in the dwarf galaxy Henize 2-10, which has no bulge. The exact implications for this invention in black hole formations are unknown, but may indicate that black holes form before the bulge.
On March 28, 2011, a supermassive black hole was seen tearing the middle star. That is the only possible explanation of the day's observations of sudden X-ray radiation and advanced broad band observations. Previous sources are inactive galaxy nuclei, and from explosions of galactic core cores is estimated to be SMBH with mass of million solar mass order. This rare event is assumed as a relativistic outflow (material emitted in jets at a significant fraction of the speed of light) of a star impaired by the SMBH. A significant portion of the solar material mass is expected to have accumulated to the SMBH. Long-term observations will then allow this assumption to be confirmed if emissions from jets decay at the expected rate for mass increase to the SMBH.
In 2012, astronomers reported an enormous mass of about 17 billion M ? for the black hole in the compact lenticular galaxy NGC 1277, located 220 million light-years away in the constellation Perseus. Putative black holes have about 59 percent of the mass of this lenticular galaxy bulge (14 percent of the total galaxy star mass). Another study reached a very different conclusion: this black hole is not too excessive, estimated between 2 and 5 billion M ? with 5 billion M ? being the most likely value. On February 28, 2013 astronomers reported the use of the NuSTAR satellite to accurately measure the round of supermassive black holes for the first time, at NGC 1365, reported that event horizons rotate almost at the speed of light.
In September 2014, data from various X-ray telescopes have shown that ultracompact dwarf galaxies are very small, dense, M60-UCD1 has 20 million solar power black holes at its center, accounting for more than 10% of the total mass of the galaxy. This discovery is quite surprising, because the black hole is five times larger than the Milky Way black hole even though the galaxy is less than five thousand mass of the Milky Way.
Some galaxies, however, do not have supermassive black holes at their center. Although most galaxies without supermassive black holes are very small, dwarf galaxies, one discovery remains mysterious: The giant AYD-giant A2261 cD galaxy has not been found to contain an active supermassive black hole, although the galaxy is one of the largest known galaxies. ; ten times the size and thousand times the mass of the Milky Way. Because supermassive black holes will only be visible as they increase, supermassive black holes are barely visible, except in effect on the star's orbit.
In December 2017, astronomers reported the most distant detection of quasars currently known, ULAS J1342 0928, containing the most distant supermassive black holes, on red redshift reported z = 7.54, exceeding the red shift 7 for the farthest quasars known previously. ULAS J1120 0641.
![A dust-bound supermassive black hole [artist's impression] | ESA ...](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_tjm78Yz-bX-yE5BwE6WL54To_VA314Fo7oH0_UjOqfKTiq899CHK68cjX9vIIyVqwZ_ITjESfzHgse-22QaS8ituKMUyPz--RsWcWKEMCLyKV7IH8pXy5KcHE0Q-soTnsqOh0Q7QcXCg=s0-d "A dust-bound supermassive black hole [artist's impression] | ESA ...")
In fiction
See also
References
Further reading
- Fulvio Melia (2003). Edge of Infinity. Supermasive Black Holes in the Universe . Cambridge University Press. ISBN: 978-0-521-81405-8.
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Laura Ferrarese & amp; David Merritt (2002). "Supermassive Black Hole". World of Physics . 15 (1): 41-46. arXiv: astro-ph/0206222 . Bibcode: 2002astro.ph..6222F. - Fulvio Melia (2007). Galactic Supermassive Black Hole . Princeton University Press. ISBN 978-0-691-13129-0.
- Merritt, David (2013). Galactic Nuclear Dynamics and Evolution . Princeton University Press. ISBN: 978-0-691-12101-7.
- Julian Krolik (1999). Galactic Nuclei On . Princeton University Press. ISBNÃ, 0-691-01151-6.
External links
- Black Hole: Interminable interactive web site winning Gravity Withdrawal About the physics and astronomy of the black hole of the Space Telescope Science Institute
- Images of supermassive black holes
- NASA images of supermassive black holes
- Black hole in the heart of Milky Way
- ESO video clip of the star orbiting the galactic black hole
- Star Orbiting Large Milky Way Center Approaching 17 Hours ESO Lamp, October 21, 2002
- Images, Animations, and New Results from UCLA Galactic Center Group
- Washington Post article on supermassive black holes
- Simulation of the stars orbiting the big black hole Milky Way
Source of the article : Wikipedia
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