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NGC 3607
NGC 3607 is a small but fairly bright lenticular galaxy in the equatorial constellation of Leo, about 2.5° south of the prominent star Delta Leonis. The galaxy was discovered March 14, 1784 by William Herschel. Dreyer described it as "very bright, large, round, very much brighter middle, 2nd of 3". It is located at a distance of 73 million light years and is receding with a radial velocity of 930 km/s. The galaxy lies southwest of NGC 3626 at an angular separation of . It occupies the center of the Leo II Group of galaxies, forming one of its two brightest members – the other being NGC 3608. It is a member of the NGC 3607 Group of galaxies, which is a member of the Leo II Groups, a series of galaxies and galaxy clusters strung out from the right edge of the Virgo Supercluster. The morphological class of NGC 3607 is SA(s)0*, matching a lenticular galaxy (SA0) with no inner ring structure (s). It is an intermediate mass galaxy that is being viewed at an inclinati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hubble Space Telescope
The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. The Hubble telescope is named after astronomer Edwin Hubble and is one of NASA's Great Observatories. The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft. Hubble features a mirror, and its five main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. Hubble's orbit outside the distortion of Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detaile ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leo II Group
The Leo II Groups, or Leo II Cloud, are a series of at least 110 galactic clusters and individual galaxies stretching approximately 30 Mly (9.2 Mpc) off the right edge of the Virgo Supercluster. It is located approximately 65 Mly (20 Mpc) to 95 Mly (29 Mpc) from the Solar System, at a right ascension of to . These clusters include: *NGC 3166 Group ** AGC 208443 ** AGC 208444 **AGC 208457 **AGC 208535 ** AGC 208537 **NGC 3156 ** NGC 3165 ** NGC 3166 ** NGC 3169 *NGC 3190 Group **NGC 3162 **NGC 3177 **NGC 3185 ** NGC 3187 ** NGC 3190 **NGC 3193 **UGC 5574 *NGC 3227 Group **NGC 3213 **NGC 3226 **NGC 3227 **UGC 5675 *NGC 3254 Group **NGC 3245A **NGC 3245 ** NGC 3254 ** NGC 3265 **NGC 3277 *NGC 3338 Group ** NGC 3338 **NGC 3346 ** NGC 3389 **UGC 5832 *NGC 3370 Group ** NGC 3370 ** NGC 3443 **NGC 3447 ** NGC 3447A ** NGC 3454 **NGC 3455 **NGC 3457 ** UGC 5945 * NGC 3396 Group ** IC 2604 **NGC 3381 ** NGC 3395 ** NGC 3396 **NGC 3424 ** NGC 3430 ** NGC 3442 *NGC 3504 Group ** NGC 3380 * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lenticular Galaxies
A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes. It contains a large-scale disc but does not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars (like elliptical galaxies). Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features and scaling relations. Both can be considered early-type galaxies that are passively evolving, at least in the local part of the Universe. Connecting the E galaxies with the S0 galaxies are the ES galaxies with intermediate-scale discs. Morphology and structure Classification Lenticular galaxies are unique in that they have a visibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective Radius
Galaxy effective radius or half-light radius (R_e) is the radius at which half of the total light of a galaxy is emitted. This assumes the galaxy has either intrinsic spherical symmetry or is at least circularly symmetric as viewed in the plane of the sky. Alternatively, a half-light contour, or isophote, may be used for spherically and circularly asymmetric objects. R_e is an important length scale in \sqrt R term in de Vaucouleurs law, which characterizes a specific rate at which surface brightness In astronomy, surface brightness (SB) quantifies the apparent brightness or flux density per unit angular area of a spatially extended object such as a galaxy or nebula, or of the night sky background. An object's surface brightness depends on it ... decreases as a function of radius: : I(R) = I_e \cdot e^ where I_e is the surface brightness at R = R_e. At R = 0, : I(R=0) = I_e \cdot e^ \approx 2000 \cdot I_e Thus, the central surface brightness is approximately 2000 \cdot I_ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dark Matter
Dark matter is a hypothetical form of matter thought to account for approximately 85% of the matter in the universe. Dark matter is called "dark" because it does not appear to interact with the electromagnetic field, which means it does not absorb, reflect, or emit electromagnetic radiation and is, therefore, difficult to detect. Various astrophysical observationsincluding gravitational effects which cannot be explained by currently accepted theories of gravity unless more matter is present than can be seenimply dark matter's presence. For this reason, most experts think that dark matter is abundant in the universe and has had a strong influence on its structure and evolution. The primary evidence for dark matter comes from calculations showing that many galaxies would behave quite differently if they did not contain a large amount of unseen matter. Some galaxies would not have formed at all and others would not move as they currently do. Other lines of evidence include observa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globular Cluster
A globular cluster is a spheroidal conglomeration of stars. Globular clusters are bound together by gravity, with a higher concentration of stars towards their centers. They can contain anywhere from tens of thousands to many millions of member stars. Their name is derived from Latin (small sphere). Globular clusters are occasionally known simply as "globulars". Although one globular cluster, Omega Centauri, was observed in antiquity and long thought to be a star, recognition of the clusters' true nature came with the advent of telescopes in the 17th century. In early telescopic observations globular clusters appeared as fuzzy blobs, leading French astronomer Charles Messier to include many of them in his catalog of astronomical objects that he thought could be mistaken for comets. Using larger telescopes, 18th-century astronomers recognized that globular clusters are groups of many individual stars. Early in the 20th century the distribution of globular clusters in the sky w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Position Angle
In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the direction of the right ascension. In the standard (non-flipped) images, this is a counterclockwise measure relative to the axis into the direction of positive declination. In the case of observed visual binary stars, it is defined as the angular offset of the secondary star from the primary relative to the north celestial pole. As the example illustrates, if one were observing a hypothetical binary star with a PA of 135°, that means an imaginary line in the eyepiece drawn from the north celestial pole to the primary (P) would be offset from the secondary (S) such that the angle would be 135°. When graphing visual binaries, the NCP is, as in the illustration, normally drawn from the center point (origin) that is the Primary downward&nd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy Morphological Classification
Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies can be classified according to their morphologies, the most famous being the Hubble sequence, devised by Edwin Hubble and later expanded by Gérard de Vaucouleurs and Allan Sandage. However, galaxy classification and morphology are now largely done using computational methods and physical morphology. Hubble sequence The Hubble sequence is a morphological classification scheme for galaxies invented by Edwin Hubble in 1926. It is often known colloquially as the “Hubble tuning-fork” because of the shape in which it is traditionally represented. Hubble's scheme divides galaxies into three broad classes based on their visual appearance (originally on photographic plates): * Elliptical galaxies have smooth, featureless light distributions and appear as ellipses in images. They are denoted by the l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgo Supercluster
The Virgo Supercluster (Virgo SC) or the Local Supercluster (LSC or LS) is a mass concentration of galaxies containing the Virgo Cluster and Local Group, which itself contains the Milky Way and Andromeda galaxies, as well as others. At least 100 galaxy groups and clusters are located within its diameter of 33 megaparsecs (110 million light-years). The Virgo SC is one of about 10 million superclusters in the observable universe and is in the Pisces–Cetus Supercluster Complex, a galaxy filament. A 2014 study indicates that the Virgo Supercluster is only a lobe of an even greater supercluster, Laniakea, a larger, competing referent of the term Local Supercluster centered on the Great Attractor. Background Beginning with the first large sample of nebulae published by William and John Herschel in 1863, it was known that there is a marked excess of nebular fields in the constellation Virgo (near the north galactic pole). In the 1950s, French–American astronomer Gérard de Vau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Galaxy Cluster
A galaxy cluster, or a cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity, with typical masses ranging from 1014 to 1015 solar masses. They are the second-largest known gravitationally bound structures in the universe after galaxy filaments and were believed to be the largest known structures in the universe until the 1980s, when superclusters were discovered. One of the key features of clusters is the intracluster medium (ICM). The ICM consists of heated gas between the galaxies and has a peak temperature between 2–15 keV that is dependent on the total mass of the cluster. Galaxy clusters should not be confused with ''galactic clusters'' (also known as open clusters), which are star clusters ''within'' galaxies, or with globular clusters, which typically orbit galaxies. Small aggregates of galaxies are referred to as galaxy groups rather than clusters of galaxies. The galaxy groups and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NGC 3607 Group
The Leo II Groups, or Leo II Cloud, are a series of at least 110 galactic clusters and individual galaxies stretching approximately 30 Mly (9.2 Mpc) off the right edge of the Virgo Supercluster. It is located approximately 65 Mly (20 Mpc) to 95 Mly (29 Mpc) from the Solar System, at a right ascension of to . These clusters include: * NGC 3166 Group ** AGC 208443 ** AGC 208444 ** AGC 208457 ** AGC 208535 ** AGC 208537 ** NGC 3156 ** NGC 3165 ** NGC 3166 **NGC 3169 *NGC 3190 Group ** NGC 3162 ** NGC 3177 **NGC 3185 ** NGC 3187 ** NGC 3190 ** NGC 3193 ** UGC 5574 * NGC 3227 Group ** NGC 3213 ** NGC 3226 ** NGC 3227 ** UGC 5675 * NGC 3254 Group ** NGC 3245A ** NGC 3245 ** NGC 3254 ** NGC 3265 ** NGC 3277 * NGC 3338 Group ** NGC 3338 ** NGC 3346 ** NGC 3389 ** UGC 5832 * NGC 3370 Group ** NGC 3370 ** NGC 3443 **NGC 3447 ** NGC 3447A ** NGC 3454 **NGC 3455 ** NGC 3457 ** UGC 5945 * NGC 3396 Group ** IC 2604 **NGC 3381 ** NGC 3395 ** NGC 3396 **NGC 3424 ** NGC 3430 ** NGC 3442 * NGC 350 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
