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M82 X-1
M82 X-1 is an ultra-luminous X-ray source located in the galaxy M82. It is a candidate intermediate-mass black hole, with the exact mass estimate varying from around 100 to 1000. One of the most luminous ULXs ever known, its luminosity exceeds the Eddington limit for a stellar mass object. See also * M82 X-2 M82 X-2 is an X-ray pulsar located in the galaxy Messier 82, approximately 12 million light-years from Earth. It is exceptionally luminous, radiating energy equivalent to approximately ten million Suns. This object is part of a binary sys ... References External links Dying Star Reveals More Evidence for New Kind of Black HoleA medium-sized black hole? Intermediate-mass black holes Ursa Major (constellation) {{Astronomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ursa Major
Ursa Major (; also known as the Great Bear) is a constellation in the northern sky, whose associated mythology likely dates back into prehistory. Its Latin name means "greater (or larger) bear," referring to and contrasting it with nearby Ursa Minor, the lesser bear. In antiquity, it was one of the original 48 constellations listed by Ptolemy in the 2nd century AD, drawing on earlier works by Greek, Egyptian, Babylonian, and Assyrian astronomers. Today it is the third largest of the 88 modern constellations. Ursa Major is primarily known from the asterism of its main seven stars, which has been called the "Big Dipper," "the Wagon," "Charles's Wain," or "the Plough," among other names. In particular, the Big Dipper's stellar configuration mimics the shape of the "Little Dipper." Two of its stars, named Dubhe and Merak ( α Ursae Majoris and β Ursae Majoris), can be used as the navigational pointer towards the place of the current northern pole star, Polaris in Ursa Mino ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ultra-luminous X-ray Source
An ultraluminous X-ray source (ULX) is an astronomical source of X-rays that is less luminous than an active galactic nucleus but is more consistently luminous than any known stellar process (over 1039 erg/s, or 1032 watts), assuming that it radiates isotropy, isotropically (the same in all directions). Typically there is about one ULX per galaxy in galaxies which host them, but some galaxies contain many. The Milky Way has not been shown to contain a ULX, although SS 433 may be a possible source. The main interest in ULXs stems from their luminosity exceeding the Eddington luminosity of neutron stars and even stellar black holes. It is not known what powers ULXs; models include beamed emission of stellar mass objects, accretion (astrophysics), accreting intermediate-mass black holes, and super-Eddington emission. Observational facts ULXs were first discovered in the 1980s by the Einstein Observatory. Later observations were made by ROSAT. Great progress has been made by the X-ray o ... [...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. Discovery M82, with M81, was discovered by Johann Elert Bode in 1774; he described it as a "nebulous patch", this one about degree away from the other, "very pale and of elongated shape". In 1779, Pierre Méchain independently rediscovered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intermediate-mass Black Hole
An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range 102–105 solar masses: significantly more than stellar black holes but less than the 105–109 solar mass supermassive black holes. Several IMBH candidate objects have been discovered in our 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, weighing 85 and 65 solar masses, with the resulting black hole weighing 142 solar masses, and 8 solar masses being radiated away as gravitational waves. Before that, the strongest evidence for IMBHs comes from a few low-luminosity active galactic nuclei. Due to their activity, these galaxies almost certainly contain accreting black holes, and in some cases the black hole masses c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eddington Limit
The Eddington luminosity, also referred to as the Eddington limit, is the maximum luminosity a body (such as a star) can achieve when there is balance between the force of radiation acting outward and the gravitational force acting inward. The state of balance is called hydrostatic equilibrium. When a star exceeds the Eddington luminosity, it will initiate a very intense radiation-driven stellar wind from its outer layers. Since most massive stars have luminosities far below the Eddington luminosity, their winds are mostly driven by the less intense line absorption. The Eddington limit is invoked to explain the observed luminosity of accreting black holes such as quasars. Originally, Sir Arthur Eddington took only the electron scattering into account when calculating this limit, something that now is called the classical Eddington limit. Nowadays, the modified Eddington limit also counts on other radiation processes such as bound-free and free-free radiation (see Bremsstrahlung) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M82 X-2
M82 X-2 is an X-ray pulsar located in the galaxy Messier 82, approximately 12 million light-years from Earth. It is exceptionally luminous, radiating energy equivalent to approximately ten million Suns. This object is part of a binary system: If the pulsar is of an average size, , then its companion is at least . On average, the pulsar rotates every 1.37 seconds, and revolves around its more massive companion every 2.5 days. M82 X-2 is an ultraluminous X-ray source (ULX), shining about 100 times brighter than theory suggests something of its mass should be able to. Its brightness is many times higher than the Eddington limit, a basic physics guideline that sets an upper limit on the brightness that an object of a given mass should be able to achieve. Possible explanations for violations of the Eddington limit include geometrical effects arising from the funneling of in-falling material along magnetic field lines. While M82 X-2 was previously known as an X-ray source, it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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