"other stars orbiting a black hole, their orbits can be used to determine the black hole's mass and location. Such observations can be used to exclude possible alternatives such as neutron stars. In this way, astronomers have identified numerous stellar black hole candidates in binary systems, and established that the radio source known as Sagittarius A*, at the core of the Milky Way galaxy, contains a supermassive black hole of about 4.3 million solar masses. On 11 February 2016, the LIGO collaboration announced the first direct detection of gravitational waves, which also represented the first observation of a black hole"
"Supermassive black hole A supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses (). Observational evidence indicates that all or nearly all massive galaxies contain a supermassive black hole, located at the galaxy's center. In the case of the Milky Way, the supermassive black hole corresponds to the location of Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering quasars and other types of active galactic nuclei. Supermassive black holes have properties that distinguish them from lower-mass classifications. First,"
"star, which is not clearly identified. Astronomers now have evidence there is a supermassive black hole at the center of the galaxy. Sagittarius A* (abbreviated Sgr A*) is agreed to be the most plausible candidate for the location of this supermassive black hole. The Very Large Telescope and Keck Telescope detected stars orbiting Sgr A* at speeds greater than that of any other stars in the galaxy. One star, designated S2, was calculated to orbit Sgr A* at speeds of over 5,000 kilometers per second at its closest approach. A gas cloud, G2, passed through the Sagittarius A* region in"
"Even these would evaporate over a timescale of up to 10 years. Supermassive black hole A supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses (). Observational evidence indicates that all or nearly all massive galaxies contain a supermassive black hole, located at the galaxy's center. In the case of the Milky Way, the supermassive black hole corresponds to the location of Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering quasars and other types of active galactic nuclei."
"CID-42 CID-42 (also known as CXOC J100043.1+020637) is a galaxy quasar about 3.9 billion light years away in the constellation Sextans. It is believed to have a supermassive black hole at its center. CID-42 is thought to be the result of a galaxy collision between two smaller galaxies. It has a distinctive trail of stars extending many light years. The discovery of a potential black hole was made after combining through the data and images taken by several telescopes including NASA's Chandra X-ray Observatory, the Hubble Telescope, the Canada-France-Hawaii Telescope and from the ground-based Magellan and Very Large Telescopes in"
"disk. Although supermassive black holes are expected to be found in most AGN, only some galaxies' nuclei have been more carefully studied in attempts to both identify and measure the actual masses of the central supermassive black hole candidates. Some of the most notable galaxies with supermassive black hole candidates include the Andromeda Galaxy, M32, M87, NGC 3115, NGC 3377, NGC 4258, NGC 4889, NGC 1277, OJ 287, APM 08279+5255 and the Sombrero Galaxy. It is now widely accepted that the center of nearly every galaxy, not just active ones, contains a supermassive black hole. The close observational correlation between"
"black hole. The reason for this assumption is the M-sigma relation, a tight (low scatter) relation between the mass of the hole in the 10 or so galaxies with secure detections, and the velocity dispersion of the stars in the bulges of those galaxies. This correlation, although based on just a handful of galaxies, suggests to many astronomers a strong connection between the formation of the black hole and the galaxy itself. The nearby Andromeda Galaxy, 2.5 million light-years away, contains a central black hole, significantly larger than the Milky Way's. The largest supermassive black hole in the Milky Way's"
"an active supermassive black hole at its core, which forms the primary component of an active galactic nucleus. The galaxy is a strong source of multiwavelength radiation, particularly radio waves. Its galactic envelope extends to a radius of about , where it is truncated—possibly by an encounter with another galaxy. Its interstellar medium consists of diffuse gas enriched by elements emitted from evolved stars. In 1781, the French astronomer Charles Messier published a catalogue of 103 objects that had a nebulous appearance as part of a list intended to identify objects that might otherwise be confused with comets. In subsequent"
"at the expected rate for mass accretion onto a SMBH. In 2012, astronomers reported an unusually large mass of approximately for the black hole in the compact, lenticular galaxy NGC 1277, which lies 220 million light-years away in the constellation Perseus. The putative black hole has approximately 59 percent of the mass of the bulge of this lenticular galaxy (14 percent of the total stellar mass of the galaxy). Another study reached a very different conclusion: this black hole is not particularly overmassive, estimated at between with being the most likely value. On 28 February 2013 astronomers reported on the"
"from the merging galaxies would collide. The Milky Way and Andromeda galaxies each contain a central supermassive black hole (SMBH), these being Sagittarius A* (ca. ) and an object within the P2 concentration of Andromeda's nucleus (). These black holes will converge near the centre of the newly formed galaxy over a period that may take millions of years, due to a process is known as dynamical friction: As the SMBHs move relative to the surrounding cloud of much less massive stars, gravitational interactions lead to a net transfer of orbital energy from the SMBHs to the stars, causing the"
"within 5 effective radii. The inner nucleus of this galaxy displays a rise in stellar orbital motion that indicates the presence of a central dark mass. The best fit model for the motion of molecular gas in the core region suggests there is a supermassive black hole with about (450 million) times the mass of the Sun. This is the first object to have its black-hole mass estimated by measuring the rotation of gas molecules around its centre with an Astronomical interferometer (in this case the Combined Array for Research in Millimeter-wave Astronomy). Supernova SN 1969E was discovered in this"
"possible to test the hypothesis that the central object is indeed a supermassive black hole to high accuracy by measuring the quadrupole moment of the gravitational field to an accuracy of a fraction of a percent. In addition, each observation of an EMRI system will allow an accurate determination of the parameters of the system, including: It is currently thought that the centers of most (large) galaxies consist of a supermassive black hole of 10 to 10 solar masses () surrounded by a cluster of 10 to 10 stars maybe 10 light-years across, called the nucleus. The orbits of the"
"use of the NuSTAR satellite to accurately measure the spin of a supermassive black hole for the first time, in NGC 1365, reporting that the event horizon was spinning at almost the speed of light. In September 2014, data from different X-ray telescopes has shown that the extremely small, dense, ultracompact dwarf galaxy M60-UCD1 hosts a 20 million solar mass black hole at its center, accounting for more than 10% of the total mass of the galaxy. The discovery is quite surprising, since the black hole is five times more massive than the Milky Way's black hole despite the galaxy"
"the region around the super-massive black hole at the centre of massive galaxies. It is hoped that this will help astronomers understand the process by which these giants formed - likely through a merging process whereby two black holes coalesce to form a more massive end product and at the same time perturbing the stellar orbits in the centre of the galaxy. At higher redshift MUSE will provide the power to construct maps of the distribution of metals in galaxies and at the same time provide constraints on the dynamical structure of these objects. Combining this with environmental information due"
"massive than the Milky Way. On December 5, 2011, astronomers measured the velocity dispersion of the central regions of two massive galaxies, NGC 4889, and the other being NGC 3842 in the Leo Cluster. According to the data of the study, they found out the central black hole of NGC 4889 is 5,200 times more massive than the central black hole of the Milky Way, or equivalent to 2.1 (21 billion) solar masses (best fit of data; possible range is from 6 billion to 37 billion solar masses). This makes it one of the most massive black holes on record."
"at the center of the Milky Way. The diameter of the black hole's immense event horizon is on the order of 118 billion kilometers, 19 times the distance from the Sun to Pluto, and has the mass equivalent to that of two dwarf galaxies. The central black hole is devouring matter and growing at a rate of 60 every year. The galaxy contains vast amounts of hot gas. More normal matter is present there than the total of all the other galaxies in the cluster. Data from observations indicate that hot gas is cooling in the central regions at a"
"is that it was over 5 times more cost efficient for its aperture size than a more traditional design. As reported in ""Nature"" of 28 November 2012, astronomers have used the Hobby–Eberly Telescope to measure the mass of an extraordinarily large black hole (with mass approximates 17 billion Suns), possibly the largest black hole found so far. It has been found in the compact, lenticular galaxy NGC 1277, which lies 220 million light-years away in the constellation Perseus. The black hole has approximately 59 percent of the mass of the bulge of this spiral galaxy (14 percent of the total"
"Central massive object Central massive object (CMO) refers to a mass concentration at the center of a galaxy. It can be either a supermassive black hole or a nuclear star cluster. The most massive galaxies are thought to always contain a supermassive black hole (SBH); these galaxies do not contain nuclear star clusters, and the CMO is identified with the SBH. Fainter galaxies usually contain a nuclear star cluster (NSC). In most of these galaxies it is not known whether a supermassive black hole is present, and the CMO is identified with the NSC. A few galaxies, for instance the"
"Quasar A quasar () (also known as a QSO or quasi-stellar object) is an extremely luminous active galactic nucleus (AGN). It has been theorized that most large galaxies contain a supermassive central black hole with mass ranging from millions to billions of times the mass of our Sun. In quasars and other types of AGN, the black hole is surrounded by a gaseous accretion disk. As gas falls toward the black hole, energy is released in the form of electromagnetic radiation, which can be observed across the electromagnetic spectrum. The power radiated by quasars is enormous: the most powerful quasars"
"bulge. In the centre of the galaxy lies a supermassive black hole whose mass is estimated to be based on the spiral arm pitch angle. The bar emerges from the opposite sides of the bulge. Straight dust lanes are observed along the bar, the one smooth and the other appearing broken. The bar has a maximum apparent length 64 arcseconds. At the end of the bar the spiral arms form a pseudoring with diameter of 71 arcseconds. Based on observations in far ultraviolet (FUV) and Hα there is active star formation at the pseudoring. Based on the B-I color profile"
"by a large burst of star formation. This current bubble is thought to have been created about one million years ago, and computer modeling suggests that there is an ongoing cycle of forming bubbles, with a new bubble forming approximately every 10 million years. Galaxies that contain an active Supermassive black hole are knowen as Seyfert galaxyies. NGC 3079 NGC 3079 is a barred spiral galaxy about 50 million light-years away, and located in the constellation Ursa Major. A prominent feature of this galaxy is the ""bubble"" forming in the very center (see picture below). The Supermassive black hole at"
"The galactic nucleus contains a bright and variable X-ray source, presumably a supermassive black hole with a mass of 20 million solar masses (15% of the mass of the entire galaxy). With this proportion of the mass of the black hole to that of the whole galaxy, it is one of the most black hole dominated galaxies known. M60-UCD1 is believed to be the stripped core of a much more massive galaxy, whose mass was stripped in an encounter with M60 some 10 billion years ago. It may yet be absorbed completely by M60, its central black hole merging with"
"holes yet found, which has a mass of , or 10,000 times the mass of the black hole at the Milky Way Galactic Center. Both quasars are 12.1 billion light years away. The most massive black hole ever discovered, TON 618, weighs in at . It is located 10.4 billion light years away from us. Some galaxies, such as the galaxy 4C +37.11, appear to have two supermassive black holes at their centers, forming a binary system. If they collided, the event would create strong gravitational waves. Binary supermassive black holes are believed to be a common consequence of galactic"
"the presence of a black hole with a mass of about (17 billion solar masses), equivalent to 14% of the total stellar mass of the galaxy, due to the motions of the stars near the center of the galaxy. This resulted in the initial claim that the black hole in NGC 1277 is one of the largest known in relation to the mass of its host galaxy. A follow-up study, based on the same data and published the following year, reached a very different conclusion. The black hole that was initially suggested at was not as massive as once thought."
"a mass of one million to one billion times that of the sun. A super-massive black hole, of more than 4 million solar masses, is located in the center of our own Milky Way galaxy. As the universe has evolved, galaxies often collide and merge, creating larger galaxies. This has led to the supposition that galaxies in mid-merge should have a two great black holes (a pair) orbiting one another. Expectations were, that this should be a common observation, hand in hand with mid merge collisions. However, observation has not validated this supposition; only a few orbiting pairs had been"
"Donald Lynden-Bell Donald Lynden-Bell CBE FRS (5 April 1935 – 6 February 2018) was a British theoretical astrophysicist. He was the first to determine that galaxies contain supermassive black holes at their centres, and that such black holes power quasars. Lynden-Bell was President of the Royal Astronomical Society (1985–87) and received numerous awards for his work, including the inaugural Kavli Prize for Astrophysics. He worked at the University of Cambridge for his entire career, where he was the first director of its Institute of Astronomy. Lynden-Bell was born at Dover Castle in Dover, Kent, into a military family, as one"
"Stellar black hole A stellar black hole (or stellar-mass black hole) is a black hole formed by the gravitational collapse of a massive star. They have masses ranging from about 5 to several tens of solar masses. The process is observed as a hypernova explosion or as a gamma ray burst. These black holes are also referred to as collapsars. By the no-hair theorem, a black hole can only have three fundamental properties: mass, electric charge and angular momentum (spin). It is believed that black holes formed in nature all have some spin. The spin of a stellar black hole"
"Planck Institute for Extraterrestrial Physics in Germany using Chilean telescopes have confirmed the existence of a supermassive black hole at the Galactic Center, on the order of 4.3 million solar masses. On 5 January 2015, NASA reported observing an X-ray flare 400 times brighter than usual, a record-breaker, from Sagittarius A*. The unusual event may have been caused by the breaking apart of an asteroid falling into the black hole or by the entanglement of magnetic field lines within gas flowing into Sagittarius A*, according to astronomers. The central cubic parsec around Sagittarius A* contains around 10 million stars. Although"
"- 8.8 Gyr. NGC 1600 has a diffuse distribution of stars near its center, caused by the influence of the galaxy's central black hole. Despite NGC 1600 being of typical size, the supermassive black hole at its center is unusually large, with a mass of 17 billion solar masses (), making it one of the largest known. At the time of the determination of the size of the black hole, in 2016, it was found to be unusual in its location in relation to the galaxy population of the region. Previously, extremely large black holes were only found in the"
"and drawing a line of best fit they ended up with a positive correlation. It appeared that the heavier the black hole at the centre was the faster the stars within the galaxy travelled. This property helped them realise that a Supermassive black hole nucleus must be the reason for the galaxies in some way. They saw that the clouds of gas before the galaxies compressed forming a black hole, the black hole would produce phenomenal amounts of energy which would force the rest of the galaxy away and form stars. Sigma comes into use when the black hole gets"
"astronomers as Cygnus X-1. Cygnus X-1 Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus, and 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 seen 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 14.8 times the mass of the Sun and has been shown to be too small to be any"
"Galactic Center The Galactic Center, or Galactic Centre, is the rotational center of the Milky Way. It is away from Earth in the direction of the constellations Sagittarius, Ophiuchus, and Scorpius where the Milky Way appears brightest. It coincides with the compact radio source Sagittarius A*. There are around 10 million stars within one parsec of the Galactic Center, dominated by red giants. There is also a significant population of massive supergiants and Wolf-Rayet stars from a star formation event around one million years ago. There is a supermassive black hole of 4.100 ± 0.034 million solar masses at the"
"it possibly provides gas to the active galactic nucleus. The mass of the supermassive black hole has been estimated based on the galaxy stellar velocity dispersion to be 10 M⊙. It has been proposed that the gas outflow has led to star formation on two locations on the bar of the galaxy which lie at the location where the gas from the nucleus encounters the dense material of the bar. Via observations of the galaxy from XMM Newton telescope in 2009, the galaxy is found to be a Compton–thick active galactic nucleus. Also the galaxy emits soft X-rays, mainly from"