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Field Galaxies
A field galaxy is a galaxy that does not belong to a larger galaxy group or cluster and hence is gravitationally alone. Roughly 80% of all galaxies located within of the Milky Way are in groups or clusters of galaxies. Most low-surface-brightness galaxies are field galaxies."An Introduction to Galaxies and Cosmology", ''David J. Adams and others'' The median Hubble-type of field galaxies is Sb, a type of spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''Local Volume, about Fur ...
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Galaxy
A galaxy is a system of stars, stellar remnants, interstellar gas, dust, dark matter, bound together by gravity. The word is derived from the Greek ' (), literally 'milky', a reference to the Milky Way galaxy that contains the Solar System. Galaxies, averaging an estimated 100 million stars, range in size from dwarfs with less than a hundred million stars, to the largest galaxies known – supergiants with one hundred trillion stars, each orbiting its galaxy's center of mass. Most of the mass in a typical galaxy is in the form of dark matter, with only a few percent of that mass visible in the form of stars and nebulae. Supermassive black holes are a common feature at the centres of galaxies. Galaxies are categorized according to their visual morphology as elliptical, spiral, or irregular. Many are thought to have supermassive black holes at their centers. The Milky Way's central black hole, known as Sagittarius A*, has a mass four million times greater than the Sun. As o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 1313
NGC 1313 (also known as the Topsy Turvy Galaxy) is a field galaxy and a barred spiral galaxy discovered by the Scottish astronomer James Dunlop on 27 September 1826. It has a diameter of about 50,000 light-years, or about half the size of the Milky Way. NGC 1313 lies within the Virgo Supercluster. In 2007, a rare WO star was discovered in NGC 1313, currently known by its only designation of C200731. It is of spectral type WO3. The derived absolute magnitude is about -5, which is very high for a single WO star. (WOs usually have absolute magnitudes of about -1 to -4) This means that the WO is likely part of a binary or a small stellar association. Two supernovae have been observed in NGC 2841: SN 1962M ( type II, mag. 11.7), and SN 1978K (type II, mag. 16). Features NGC 1313 has a strikingly uneven shape and its axis of rotation is not exactly in its centre. NGC 1313 also shows strong starburst activity and associated supershells. NGC 1313 is dominated by scattered patche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coma Berenices
Coma Berenices is an ancient asterism in the northern sky, which has been defined as one of the 88 modern constellations. It is in the direction of the fourth galactic quadrant, between Leo and Boötes, and it is visible in both hemispheres. Its name means "Berenice's Hair" in Latin and refers to Queen Berenice II of Egypt, who sacrificed her long hair as a votive offering. It was introduced to Western astronomy during the third century BC by Conon of Samos and was further corroborated as a constellation by Gerardus Mercator and Tycho Brahe. It is the only modern constellation named for a historic person. The constellation's major stars are Alpha, Beta, and Gamma Comae Berenices. They form a half square, along the diagonal of which run Berenice's imaginary tresses, formed by the Coma Star Cluster. The constellation's brightest star is Beta Comae Berenices, a 4.2-magnitude main sequence star similar to the Sun. Coma Berenices contains the North Galactic Pole and one of the r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 4136
NGC commonly refers to: * New General Catalogue of Nebulae and Clusters of Stars, a catalogue of deep sky objects in astronomy NGC may also refer to: Companies * NGC Corporation, name of US electric company Dynegy, Inc. from 1995 to 1998 * National Gas Company of Trinidad and Tobago, state-owned natural gas company in Trinidad and Tobago * National Grid plc, a former name of National Grid Electricity Transmission plc, the operator of the British electricity transmission system * Northrop Grumman Corporation, aerospace and defense conglomerate formed from the merger of Northrop Corporation and Grumman Corporation in 1994 * Numismatic Guaranty Corporation, coin certification company in the United States Other uses * National Gallery of Canada, art gallery founded in 1880 in Ottawa, Canada * National Geographic, documentary and reality television channel established in the United States in 2001 formerly called National Geographic Channel * Native Girls Code, US non-profit organi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydra (constellation)
Hydra is the largest of the 88 modern constellations, measuring 1303 square degrees, and also the longest at over 100 degrees. Its southern end borders Libra and Centaurus and its northern end borders Cancer. It was included among the 48 constellations listed by the 2nd century astronomer Ptolemy. Commonly represented as a water snake, it straddles the celestial equator. History and mythology Western mythology The Greek constellation of Hydra is an adaptation of a Babylonian constellation: the MUL.APIN includes a "serpent" constellation (MUL.DINGIR.MUŠ) that loosely corresponds to Hydra. It is one of two Babylonian "serpent" constellations (the other being the origin of the Greek Serpens), a mythological hybrid of serpent, lion and bird. The shape of Hydra resembles a twisting snake, and features as such in some Greek myths. One myth associates it with a water snake that a crow served Apollo in a cup when it was sent to fetch water; Apollo saw through the fraud, and angr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 3621
NGC 3621 is a field spiral galaxy about away in the equatorial constellation of Hydra. It is comparatively bright and can be well seen in moderate-sized telescopes. The galaxy is around across and is inclined at an angle of 25° from being viewed edge on. It shines with a luminosity equal to 13 billion times that of the Sun. The morphological classification is SA(s)d, which indicates this is an ordinary spiral with loosely wound arms. There is no evidence for a bulge. Although it appears to be isolated, NGC 3621 belongs to the Leo spur. This galaxy has an active nucleus that matches a Seyfert 2 optical spectrum, suggesting that a low mass supermassive black hole is present at the core. Based upon the motion of stars in the nucleus, this object may have a mass of up to three million times the mass of the Sun. Gallery File:NGC 3621 HST.jpg, Part of NGC 3621 imaged by HST. File:NGC 3621 ESO VLT.jpg, Very Large Telescope image of NGC 3621. File:NGC 3621 Hubble WikiSky.j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sextans (constellation)
Sextans is a minor equatorial constellation which was introduced in 1687 by Johannes Hevelius. Its name is Latin for the astronomical sextant, an instrument that Hevelius made frequent use of in his observations. Notable features Sextans as a constellation covers a rather dim, sparse region of the sky. It has only one star above the fifth magnitude, namely α Sextantis at 4.49m. The constellation contains a few double stars, including γ, 35, and 40 Sextantis. There are a few notable variable stars, including β, 25, 23 Sextantis, and LHS 292. NGC 3115, an edge-on lenticular galaxy, is the only noteworthy deep-sky object. It also lies near the ecliptic, which causes the Moon, and some of the planets to occasionally pass through it for brief periods of time. The constellation is the location of the field studied by the COSMOS project, undertaken by the Hubble Space Telescope. Sextans B is a fairly bright dwarf irregular galaxy at magnitude 6.6, 4.3 million lig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 3115
NGC 3115 (also called the Spindle Galaxy or Caldwell 53) is a field lenticular (S0) galaxy in the constellation Sextans. The galaxy was discovered by William Herschel on February 22, 1787. At about 32 million light-years away from Earth, it is several times bigger than the Milky Way. It is a lenticular (S0) galaxy because it contains a disk and a central bulge of stars, but without a detectable spiral pattern. NGC 3115 is seen almost exactly edge-on, but was nevertheless mis-classified as elliptical. There is some speculation that NGC 3115, in its youth, was a quasar. Star formation NGC 3115 has consumed most of the gas of its youthful accretion disk. It has very little gas and dust left that would trigger new star formation. The vast majority of its component stars are very old. Black hole In 1992 John Kormendy of the University of Hawaii and Douglas Richstone of the University of Michigan announced what was observed to be a supermassive black hole in the galaxy.Kormendy, J. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leo (constellation)
Leo is one of the constellations of the zodiac, between Cancer (constellation), Cancer the crab to the west and Virgo (constellation), Virgo the maiden to the east. It is located in the Northern celestial hemisphere. Its name is Latin for lion, and to the ancient Greeks represented the Nemean Lion killed by the mythical Greek hero Heracles meaning 'Glory of Hera' (known to the ancient Romans as Hercules) as one of his Twelve Labours, twelve labors. Its old astronomical symbol is (♌︎). One of the 48 constellations described by the 2nd-century astronomer Ptolemy, Leo remains one of the 88 modern constellations today, and one of the most easily recognizable due to its many bright stars and a distinctive shape that is reminiscent of the crouching lion it depicts. The lion's mane and shoulders also form an asterism (astronomy), asterism known as "The Sickle," which to modern observers may resemble a backwards "question mark." Features Stars Leo contains many bright stars, many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 2903
NGC 2903 is an isolated barred spiral galaxy in the equatorial constellation of Leo, positioned about 1.5° due south of Lambda Leonis. It was discovered by German-born astronomer William Herschel, who cataloged it on November 16, 1784. He mistook it as a double nebula, as did subsequent observers, and it wasn't until the nineteenth century that the Third Earl of Rosse resolved into a spiral form. J. L. E. Dreyer assigned it the identifiers 2903 and 2905 in his '' New General Catalogue''; NGC 2905 now designates a luminous knot in the northeastern spiral arm. This field galaxy is located about 30 million light-years away from the Milky Way, and is a member of the Virgo Supercluster. The morphological classification of this galaxy is SBbc, indicating a barred spiral (SB) with moderate to tightly-wound spiral arms (bc). De Vaucouleurs and associates assigned it the class SAB(rs)bc, suggesting a weaker bar structure (SAB) with a partial ring (rs). The bar structure ap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynx (constellation)
Lynx is a constellation named after the animal, usually observed in the Northern Celestial Hemisphere. The constellation was introduced in the late 17th century by Johannes Hevelius. It is a faint constellation, with its brightest stars forming a zigzag line. The orange giant Alpha Lyncis is the brightest star in the constellation, and the semiregular variable star Y Lyncis is a target for amateur astronomers. Six star systems have been found to contain planets. Those of 6 Lyncis and HD 75898 were discovered by the Doppler method; those of XO-2, XO-4, XO-5 and WASP-13 were observed as they passed in front of the host star. Within the constellation's borders lie NGC 2419, an unusually remote globular cluster; the galaxy NGC 2770, which has hosted three recent Type Ib supernovae; the distant quasar APM 08279+5255, whose light is magnified and split into multiple images by the gravitational lensing effect of a foreground galaxy; and the Lynx Supercluster, which was the m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 2683
NGC 2683 is a field spiral galaxy in the northern constellation of Lynx. It was nicknamed the "UFO Galaxy" by the Astronaut Memorial Planetarium and Observatory. It was discovered by the astronomer William Herschel on February 5, 1788. It is viewed nearly edge-on from Earth's location in space and is located about 30 million light-years away, although previous estimates also give distances between 16 and 25 million light-years. NGC 2683 is receding from Earth at , and from the Galactic Center at . Visibility The reddened light from the center of the galaxy appears yellowish due to the intervening gas and dust located within the outer arms of NGC 2683. Its apparent magnitude is 10.6 making it not visible to the human eye without the aid of a small telescope. Characteristics While usually considered an unbarred spiral galaxy, recent research suggests it may in fact be a barred spiral galaxy; its bar is hard to see due to its high inclination. Further support for the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
