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Intermediate-mass Black Hole
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. Observational evidence The gravitational wave signal GW190521, which occurred on 21 May 2019 at 03:02:29 UTC, and was published on 2 September 2020, resulted from the merger of two black holes. They had masses of 85 and 65 solar masses and merged to form a black hole of 142 solar masses, with 8 solar masses radiated away as gravitational waves. Before that, the strongest evidence for IMBHs came from a few low-luminosity active galactic nuclei. Due to their activity, these gal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HST G1 (Mayall II)
HST may refer to: People * Harry S. Truman (1884–1972), 33rd president of the US * Hunter S. Thompson (1937–2005), American journalist and author Science and technology * Hubble Space Telescope * Harvard–MIT Program in Health Sciences and Technology * History of science and technology * High-speed telegraphy, a radiosport * High-Speed Transfer, a USRobotics modem protocol * Highstand systems tract, in the sequence stratigraphy#Systems tracts, sequence stratigraphy branch of geology Transportation and military * Hastings railway station, Melbourne (Station code), Australia * Helicopter support team, in the US Marine Corps * Helsinki City Transport (Swedish: ') * Heritage Shunters Trust, an English rail preservation society * High-speed train, a type of rail transport ** InterCity 125 or High Speed Train, UK * High Street (Glasgow) railway station (station code), Scotland * High Sierra Trail, in California, US * Homestead Air Reserve Base (IATA code), Florida, US * USS Harry S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverberation Mapping
Reverberation mapping (or Echo mapping) is an astrophysical technique for measuring the structure of the broad-line region (BLR) around a supermassive black hole at the center of an active galaxy, and thus estimating the hole's mass. It is considered a "primary" mass estimation technique, i.e., the mass is measured directly from the motion that its gravitational force induces in the nearby gas. Newton's law of gravity defines a direct relation between the mass of a central object and the speed of a smaller object in orbit around the central mass. Thus, for matter orbiting a black hole, the black-hole mass M_\bullet is related by the formula : GM_\bullet = f \, R_\text \, (\Delta V)^2 to the RMS velocity Δ''V'' of gas moving near the black hole in the broad emission-line region, measured from the Doppler broadening of the gaseous emission lines. In this formula, ''R''BLR is the radius of the broad-line region; ''G'' is the constant of gravitation; and ''f'' is a poo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A Black Hole Of Puzzling Lightness
A, or a, is the first letter and the first vowel letter of the Latin alphabet, used in the modern English alphabet, and others worldwide. Its name in English is '' a'' (pronounced ), plural ''aes''. It is similar in shape to the Ancient Greek letter alpha, from which it derives. The uppercase version consists of the two slanting sides of a triangle, crossed in the middle by a horizontal bar. The lowercase version is often written in one of two forms: the double-storey and single-storey . The latter is commonly used in handwriting and fonts based on it, especially fonts intended to be read by children, and is also found in italic type. In English, '' a'' is the indefinite article, with the alternative form ''an''. Name In English, the name of the letter is the ''long A'' sound, pronounced . Its name in most other languages matches the letter's pronunciation in open syllables. History The earliest known ancestor of A is ''aleph''—the first letter of the Phoenician ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M–sigma Relation
The M–sigma (or ''M''–''σ'') relation is an empirical correlation between the stellar velocity dispersion ''σ'' of a galaxy bulge and the mass M of the supermassive black hole at its center. The ''M''–''σ'' relation was first presented in 1999 during a conference at the Institut d'Astrophysique de Paris in France. The proposed form by David Merritt of the relation, which was called the "Faber–Jackson law for black holes", was : \frac \approx 3.1\left(\frac\right)^4. where M_\odot is the solar mass. Publication of the relation in a refereed journal, by two groups, took place the following year. One of many recent studies, based on the growing sample of published black hole masses in nearby galaxies, givesMcConnell, N. J. et al. (2011) Two ten-billion-solar-mass black holes at the centres of giant elliptical galaxies ''Nature'', 480, 215–218 : \frac \approx 1.9\left(\frac\right)^. Earlier work demonstrated a relationship between galaxy luminosity and black hol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Birmingham
The University of Birmingham (informally Birmingham University) is a Public university, public research university in Birmingham, England. It received its royal charter in 1900 as a successor to Queen's College, Birmingham (founded in 1825 as the William Sands Cox, Birmingham School of Medicine and Surgery), and Mason Science College (established in 1875 by Sir Josiah Mason), making it the first English red brick university, civic or 'red brick' university to receive its own royal charter, and the first English Collegiate university, unitary university. It is a founding member of both the Russell Group of British research universities and the international network of research universities, Universitas 21. The student population includes undergraduate and postgraduate students (), which is the List of universities in the United Kingdom by enrollment, largest in the UK (out of ). The annual income of the university for 2023–24 was £926 million of which £205.2 mil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stellar Remnant
In astronomy, the term compact object (or compact star) refers collectively to white dwarfs, neutron stars, and black holes. It could also include exotic stars if such hypothetical, dense bodies are confirmed to exist. All compact objects have a high mass relative to their radius, giving them a very high density, compared to ordinary atomic matter. Compact objects are often the endpoints of stellar evolution and, in this respect, are also called stellar remnants. They can also be called dead stars in public communications. The state and type of a stellar remnant depends primarily on the mass of the star that it formed from. The ambiguous term ''compact object'' is often used when the exact nature of the star is not known, but evidence suggests that it has a very small radius compared to ordinary stars. A compact object that is not a black hole may be called a degenerate star. In June 2020, astronomers reported narrowing down the source of Fast Radio Bursts (FRBs), which may ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Radiation
Gravitational waves are oscillations of the gravitational field that travel through space at the speed of light; they are generated by the relative motion of gravitating masses. They were 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. Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation. Newton's law of universal gravitation, part of classical mechanics, does not provide for their existence, instead asserting that gravity has instantaneous effect everywhere. Gravitational waves therefore stand as an important relativistic phenomenon that is absent from Newtonian physics. Gravitational-wave astronomy has the advantage that, unlike electromagnetic radiation, gravitational waves are no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M31 G1
Mayall II, also known as NGC-224-G1, SKHB 1, GSC 2788:2139, HBK 0-1, M31GC J003247+393440 or Andromeda's Cluster, is a globular cluster orbiting M31, the Andromeda Galaxy. It is located from the Andromeda Galaxy's galactic core, and is the brightest (by absolute magnitude) globular cluster in the Local Group, with an absolute visual magnitude of −10.94 and the luminosity of 2 million Suns. It has an apparent magnitude of 13.81 in V band. Mayall II is considered to have twice the mass of Omega Centauri, and may contain a central, intermediate-mass (~ 2 M⊙) black hole. It was first identified as a possible globular cluster by American astronomers Nicholas Mayall and Olin J. Eggen in 1953 using a Palomar Schmidt plate exposed in 1948. Because of the widespread distribution of metallicity, indicating multiple star A star is a luminous spheroid of plasma (physics), plasma held together by Self-gravitation, self-gravity. The List of nearest stars and brown dwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Letters
Letter, letters, or literature may refer to: Characters typeface * Letter (alphabet), a character representing one or more of the sounds used in speech or none in the case of a silent letter; any of the symbols of an alphabet * Letterform, the graphic form of a letter of the alphabet, either as written or in a particular type font * Rehearsal letter in an orchestral score Communication * Letter (message), a form of written communication ** Mail * Letters, the collected correspondence of a writer or historically significant person **Pauline epistles, addressed by St. Paul to various communities or congregations, such as "Letters to the Galatians" or "Letters to the Corinthians", and part of the canonical books of the Bible ** Maktubat (other), the Arabic word for collected letters * The letter as a form of second-person literature; see Epistle ** Epistulae (Pliny) ** Epistolary novel, a long-form fiction composed of letters (epistles) * Open letter, a public letter as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 82
Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy approximately 12 million light-years away in the constellation Ursa Major. It is the second-largest member of the M81 Group, with the D25 isophotal diameter of . It is about five times more luminous than the Milky Way and its central region is about one hundred times more luminous. The starburst activity is thought to have been triggered by interaction with neighboring galaxy M81. As one of the closest starburst galaxies to Earth, M82 is the prototypical example of this galaxy type. SN 2014J, a type Ia supernova, was discovered in the galaxy on 21 January 2014. In 2014, in studying M82, scientists discovered the brightest pulsar yet known, designated M82 X-2. In November 2023, a gamma-ray burst was observed in M82, which was determined to have come from a magnetar, the first such event detected outside the Milky Way (and only the fourth such event ever detected). Discovery M82, with M81, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Star Formation
Star formation is the process by which dense regions within molecular clouds in interstellar space—sometimes referred to as "stellar nurseries" or "star-forming regions"—Jeans instability, collapse and form stars. As a branch of astronomy, star formation includes the study of the interstellar medium (ISM) and giant molecular clouds (GMC) as precursors to the star formation process, and the study of protostars and young stellar objects as its immediate products. It is closely related to planet formation, another branch of astronomy. Star formation theory, as well as accounting for the formation of a single star, must also account for the statistics of binary stars and the initial mass function. Most stars do not form in isolation but as part of a group of stars referred as star clusters or stellar associations. First stars Star formation is divided into three groups called "Populations". Population III stars formed from primordial hydrogen after the Big Bang. These stars are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
