58 relations: Active galactic nucleus, Alpha Ursae Majoris, Amateur astronomy, Andromeda Galaxy, Aperture, Astronomer, Astrophysics (journal), Binoculars, Cambridge University Press, Central Bureau for Astronomical Telegrams, Charles Messier, Constellation, Cosmic dust, Earth, Galaxies in fiction, Galaxy group, Helium, Hydrogen, IAU Circular, Interacting galaxy, Interstellar medium, Johann Elert Bode, Light-year, List of galaxies, List of Messier objects, Local Group, Low-ionization nuclear emission-line region, M81 Group, Messier 82, Messier object, Micrometre, Milky Way, Minute and second of arc, Nature (journal), New General Catalogue, NGC 3077, Nova, Parsec, Pierre Méchain, Polycyclic aromatic hydrocarbon, Principal Galaxies Catalogue, SN 1993J, Spectral line, Spiral galaxy, Spitzer Space Telescope, Star formation, Starburst galaxy, Stellar classification, Supermassive black hole, Supernova, ..., Telescope, The Astronomical Journal, The Astrophysical Journal, Triangulum Galaxy, Uppsala General Catalogue, Ursa Major, Virgo Supercluster, 10 zettametres. Expand index (8 more) » « Shrink index
An active galactic nucleus (AGN) is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion – and possibly all – of the electromagnetic spectrum.
Alpha Ursae Majoris (Alpha UMa, α Ursae Majoris, α UMa) is the second-brightest star in the constellation of Ursa Major (despite its Bayer designation of "alpha").
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Amateur astronomy is a hobby whose participants enjoy watching the sky, and the abundance of objects found in it with the unaided eye, binoculars, or telescopes.
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The Andromeda Galaxy, also known as Messier 31, M31, or NGC 224, is a spiral galaxy approximately 780 kiloparsecs (2.5 million light-years) from Earth.
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In optics, an aperture is a hole or an opening through which light travels.
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An astronomer is a scientist in the field of astronomy who studies stars, planets, moons, comets, and galaxies, as well as many other celestial objects.
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Astrophysics is a peer-reviewed scientific journal of astrophysics published by Springer.
Binoculars, field glasses or binocular telescopes are a pair of identical or mirror-symmetrical telescopes mounted side-by-side and aligned to point accurately in the same direction, allowing the viewer to use both eyes (binocular vision) when viewing distant objects.
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Cambridge University Press (CUP) is the publishing business of the University of Cambridge.
The Central Bureau for Astronomical Telegrams (CBAT) is the official international clearing house for information relating to transient astronomical events.
Charles Messier (26 June 1730 – 12 April 1817) was a French astronomer most notable for publishing an astronomical catalogue consisting of nebulae and star clusters that came to be known as the 110 "Messier objects".
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In modern astronomy, a constellation is a specific area of the celestial sphere as defined by the International Astronomical Union (IAU).
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Cosmic dust is dust which exists in space.
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Earth (also the world, in Greek: Gaia, or in Latin: Terra), is the third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to accommodate life.
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Galaxies other than the Milky Way are popular settings for creators of science fiction, particularly those working with broad-scale space opera settings.
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A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxies larger than groups that are first-order clustering are called galaxy clusters.
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Helium is a chemical element with symbol He and atomic number 2.
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Hydrogen is a chemical element with chemical symbol H and atomic number 1.
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The International Astronomical Union Circulars (IAUCs) are notices that give information about astronomical phenomena.
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Interacting galaxies (colliding galaxies) are galaxies whose gravitational fields result in a disturbance of one another.
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In astronomy, the interstellar medium (ISM) is the matter that exists in the space between the star systems in a galaxy.
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Johann Elert Bode (19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularization of the Titius–Bode law.
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A light-year (abbreviation: ly), sometimes written light year, is a unit of length used informally to express astronomical distances.
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The following is a list of notable galaxies.
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The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his "Catalogue des Nébuleuses et des Amas d'Étoiles" ("Catalogue of Nebulae and Star Clusters").
The Local Group is the galaxy group that includes the Milky Way.
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A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission.
The M81 Group is a galaxy group in the constellations Ursa Major and Camelopardalis that includes the well-known galaxies Messier 81 and Messier 82, as well as several other galaxies with high apparent brightnesses.
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Messier 82 (also known as NGC 3034, Cigar Galaxy or M82) is a starburst galaxy about 12 million light-years away in the constellation Ursa Major.
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The Messier objects are a set of over 100 astronomical objects first listed by French astronomer Charles Messier in 1771.
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The micrometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: µm) or micrometer (American spelling), also commonly known as a micron, is an SI derived unit of length equaling 1×10−6 of a metre (SI standard prefix "micro-".
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The Milky Way is the galaxy that contains our Solar System.
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A minute of arc (MOA), arcminute (arcmin) or minute arc is a unit of angular measurement equal to one-sixtieth of one degree.
Nature is a British interdisciplinary scientific journal, first published on 4 November 1869.
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The New General Catalogue of Nebulae and Clusters of Stars (abbreviated as NGC) is a well-known catalogue of deep-sky objects in astronomy compiled by John Louis Emil Dreyer in 1888, as a new version of John Herschel's Catalogue of Nebulae and Clusters of Stars.
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NGC 3077 is a smaller member of the M81 Group.
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A nova (plural novae or novas) is a cataclysmic nuclear explosion on a white dwarf, which causes a sudden brightening of the star.
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A parsec (symbol: pc) is a unit of length used to measure the astronomically large distances to objects outside the Solar System.
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Pierre François André Méchain (16 August 1744 – 20 September 1804) was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep sky objects and comets.
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Polycyclic aromatic hydrocarbons (PAHs, also polyaromatic hydrocarbons) are hydrocarbons—organic compounds containing only carbon and hydrogen—that are composed of multiple aromatic rings (organic rings in which the electrons are delocalized).
The Catalogue of Principal Galaxies (PGC) is an astronomical catalog published in 1989 that lists B1950 and J2000 equatorial coordinates and cross-identifications for 73,197 galaxies.
SN 1993J is a supernova observed in the galaxy M81.
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A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.
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A spiral galaxy is a certain kind of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae(pp. 124–151) and, as such, forms part of the Hubble sequence.
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The Spitzer Space Telescope (SST), formerly the Space Infrared Telescope Facility (SIRTF), is an infrared space observatory launched in 2003.
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", collapse to form stars.
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A starburst galaxy is a galaxy undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy or the star formation rate observed in most other galaxies.
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In astronomy, stellar classification is the classification of stars based on their spectral characteristics.
A supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses, and is found in the center of almost all massive galaxies.
A supernova is a stellar explosion that briefly outshines an entire galaxy, radiating as much energy as the Sun or any ordinary star is expected to emit over its entire life span, before fading from view over several weeks or months.
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A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation (such as visible light).
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The Astronomical Journal (often abbreviated AJ in scientific papers and references) is a peer-reviewed monthly scientific journal owned by the American Astronomical Society and currently published by IOP Publishing.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.
The Triangulum Galaxy is a spiral galaxy approximately 3 million light-years (ly) from Earth in the constellation Triangulum.
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The Uppsala General Catalogue of Galaxies (UGC) is a catalogue of 12921 galaxies visible from the northern hemisphere.
Ursa Major (also known as the Great Bear and Charles' Wain) is a constellation in the northern celestial hemisphere.
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The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galaxies that contains the Virgo Cluster in addition to the Local Group, which in turn contains the Milky Way and Andromeda Galaxies.
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To help compare different orders of magnitude, this page lists distances starting at 10 Zm (1022 m or 1.1 million light years).
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