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Local Group
The Local Group is the galaxy group that includes the Milky Way. It has a total diameter of roughly , and a total mass of the order of . It consists of two collections of galaxies in a " dumbbell" shape; the Milky Way and its satellites form one lobe, and the Andromeda Galaxy and its satellites constitute the other. The two collections are separated by about and are moving toward one another with a velocity of . The group itself is a part of the larger Virgo Supercluster, which may be a part of the Laniakea Supercluster. The exact number of galaxies in the Local Group is unknown as some are occluded by the Milky Way; however, at least 80 members are known, most of which are dwarf galaxies. The two largest members, the Andromeda and the Milky Way galaxies, are both spiral galaxies with masses of about solar masses each. Each has its own system of satellite galaxies: * The Andromeda Galaxy's satellite system consists of Messier 32 (M32), Messier 110 (M110), NGC 147, NGC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Messier 31
Messier may refer to: People with the surname *Charles Messier, French astronomer *Éric Messier, former NHL defenseman *George Messier, French inventor *Jean-Marie Messier, former CEO of Vivendi Universal *Marc Messier, Canadian actor from Quebec *Mark Messier, former NHL player, Hall of fame class 2007 *Paul Arthur Messier, art conservator Other uses *Messier object, a set of 110 astronomical objects *Messier (crater) *Messier (automobile) Messier was a French automobile manufacturer, based at Montrouge, on the southern edge of Paris, from 1925 till 1931.Linz, Schrader: ''Die Internationale Automobil-Enzyklopädie.''Georgano: ''The Beaulieu Encyclopedia of the Automobile.''Georgan ..., a French car produced 1925–1931 * Messier-Dowty and preceding companies in manufacture of aircraft undercarriage {{disambiguation, surname French-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda I
Andromeda I is a dwarf spheroidal galaxy (dSph) about 2.40 million light-years away in the constellation Andromeda. Andromeda I is part of the local group of galaxies and a satellite galaxy of the Andromeda Galaxy (M31). It is roughly 3.5 degrees south and slightly east of M31. As of 2005, it is the closest known dSph companion to M31 at an estimated projected distance of ~40 kpc or ~150,000 light-years. Andromeda I was discovered by Sidney van den Bergh in 1970 with the Mount Palomar Observatory 48-inch telescope. Further study of Andromeda I was done by the WFPC2 camera of the Hubble Space Telescope. This found that the horizontal branch stars, like other dwarf spheroidal galaxies were predominantly red. From this, and the abundance of blue horizontal branch stars, along with 99 RR Lyrae stars detected in 2005, lead to the conclusion there was an extended epoch of star formation. The estimated age is approximately 10 Gyr. The Hubble telescope also found a globular cluste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwarf Spheroidal Galaxies
A dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population. They are found in the Local Group as companions to the Milky Way and to systems that are companions to the Andromeda Galaxy (M31). While similar to dwarf elliptical galaxies in appearance and properties such as little to no gas or dust or recent star formation, they are approximately spheroidal in shape and generally have lower luminosity. Discovery Despite the radii of dSphs being much larger than those of globular clusters, they are much more difficult to find due to their low luminosities and surface brightnesses. Dwarf spheroidal galaxies have a large range of luminosities, and known dwarf spheroidal galaxies span several orders of magnitude of luminosity. Their luminosities are so low that Ursa Minor, Carina, and Draco, the known dwarf spheroidal galaxies with the lowest luminosities, have mass-to-light ratios (M/L) greate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda XXII
Andromeda XXII (Pisces VI, Triangulum I) is a low surface brightness dwarf spheroidal galaxy about away from the Sun in the constellation Pisces, of the Local Group. Andromeda XXII is located much closer in projection to M33 than M31 vs. This fact suggests that it might be the first Triangulum (M33) satellite ever discovered. However, it is currently catalogued as a satellite of Andromeda (M31).Nicolas F. Martin, Alan W. McConnachie, Mike Irwin, Lawrence M. Widrow, Annette M. N. Ferguson, Rodrigo A. Ibata, John Dubinski, Arif Babul, Scott Chapman, Mark Fardal, Geraint F. Lewis, Julio Navarro, R. Michael Rich; "PAndAS' cubs: discovery of two new dwarf galaxies in the surroundings of the Andromeda and Triangulum galaxies"; The Astrophysical Journal, Volume 705, Issue 1, pp. 758-765 (2009); ; ; ; The discovery arose from the first year data of a photometric survey of the M31/ M33 subgrouping of the Local Group by the Pan-Andromeda Archaeological Survey (PAndAS). This survey was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda XXI
Andromeda XXI (And 21, And XXI) is a moderately bright dwarf spheroidal galaxy about away from the Sun in the constellation Andromeda. It is the fourth largest Local Group dwarf spheroidal galaxy. The discovery arose from the first year data of a photometric survey of the M31/ M33 subgroupings of the Local Group by the Pan-Andromeda Archaeological Survey (PAndAS). This survey was conducted with the Megaprime/MegaCam wide-field camera mounted on the Canada-France-Hawaii Telescope. This large satellite of the Andromeda Galaxy (M31) has a half-light radius of roughly 1 kpc.Nicolas F. Martin, Alan W. McConnachie, Mike Irwin, Lawrence M. Widrow, Annette M. N. Ferguson, Rodrigo A. Ibata, John Dubinski, Arif Babul, Scott Chapman, Mark Fardal, Geraint F. Lewis, Julio Navarro, R. Michael Rich; "PAndAS' cubs: discovery of two new dwarf galaxies in the surroundings of the Andromeda and Triangulum galaxies"; The Astrophysical Journal, Volume 705, Issue 1, pp. 758-765 (2009); ; ; ; Andr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda XIX
Andromeda XIX is a satellite galaxy of the Andromeda Galaxy (M31), a member of the Local Group, like the Milky Way Galaxy. Andromeda XIX is considered "the most extended dwarf galaxy known in the Local Group", and has been shown to have a half-light radius of 1.7 kiloparsec (kpc). It was discovered by the Canada–France–Hawaii Telescope The Canada–France–Hawaii Telescope (CFHT) is located near the summit of Mauna Kea mountain on Hawaii's Big Island at an altitude of 4,204 meters (13,793 feet), part of the Mauna Kea Observatory. Operational since 1979, the telescope is a Pri ..., and is thought to be a dwarf galaxy. As with other dwarf galaxies, Andromeda XIX is not producing new stars: 90% of its star formation occurred over 9 billion years ago. However, compared to dwarf galaxies of similar mass Andromeda XIX is extremely diffuse, like Antlia II. History Surveillance performed during use of the MegaPrime/MegaCam 1 deg2 (camera) on the Canada-France-Hawaii Telescop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda XI
Andromeda XI (And 11) is a dwarf spheroidal galaxy about 2.6 million light-years away from the Sun in the constellation Andromeda. Discovered in 2006, And XI is a satellite galaxy of the Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ... (M31). See also * List of Andromeda's satellite galaxies References {{DEFAULTSORT:Andromeda XI Andromeda (constellation) Dwarf spheroidal galaxies Astronomical objects discovered in 2006 Andromeda Subgroup Local Group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda X
Andromeda X (And 10) is a dwarf spheroidal galaxy about 2.9 million light-years away from the Sun in the constellation Andromeda. Discovered in 2005 by Zucker et al., And X is a satellite galaxy of the Andromeda Galaxy (M31). Aided by the application of stellar photometry to data from the Sloan Digital Sky Survey similar to the Andromeda IX discovery, the new finding indicates that this type of extremely faint satellite might be common in the Lower Group, potentially providing further support for hierarchical cold dark matter In cosmology and physics, cold dark matter (CDM) is a hypothetical type of dark matter. According to the current standard model of cosmology, Lambda-CDM model, approximately 27% of the universe is dark matter and 68% is dark energy, with only a sm ... models. See also * List of Andromeda's satellite galaxies References External links SEDS webpage for Andromeda X Dwarf spheroidal galaxies 5056921 Local Group Andromeda Subgroup Andromeda (c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda IX
Andromeda IX (And 9) is a dwarf spheroidal satellite of the Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala .... It was discovered in 2004 by resolved stellar photometry from the Sloan Digital Sky Survey (SDSS), by Zucker et al. (2004). At the time of its discovery, it was the galaxy with the lowest known surface brightness, Σ''V'' ≃ 26.8mags arcsec−2 and the faintest galaxy known from its intrinsic absolute brightness. It was found from data acquired within an SDSS scan along the major axis of M31, on October 5, 2002. Its distance was estimated to be almost exactly the same as that of M31 by McConnacrchie et al. (2005). See also * List of Andromeda's satellite galaxies References External linksSEDS webpage for Andromeda IX {{DEFAULTSORT:Andromeda 09 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andromeda VIII
Andromeda VIII (And VIII / 8) is a galaxy discovered in August 2003. It is a companion galaxy to the Andromeda Galaxy, M31, and evaded detection for so long due to its diffuse nature. The galaxy was finally discovered by measuring the redshifts of stars in front of Andromeda, which proved to have different velocities Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity is a ... than M31 and hence were part of a different galaxy. As of at least 2006, the actuality of And VIII as a galaxy has not yet been firmly established (Merrett et al. 2006). See also * List of Andromeda's satellite galaxies References External linksSEDS Webpage for Andromeda VIII {{DEFAULTSORT:Andromeda 08 Andromeda Subgroup Local Group Andromeda (constellation) Dwarf spheroidal galaxies 5056928 Astronom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cassiopeia Dwarf
The Cassiopeia Dwarf (also known as Andromeda VII) is a dwarf spheroidal galaxy about 2.45 Mly away in the constellation Cassiopeia. The Cassiopeia Dwarf is part of the Local Group and a satellite galaxy of the Andromeda Galaxy (M31). In the sky, it appears behind the Milky Way's galactic plane, and so it is reddened by 0.194 magnitudes. With a luminosity of and a stellar mass of , it is the brightest and most massive of the Andromeda Galaxy's dwarf spheroidal galaxy satellites. It also has the highest metallicity out of all of them. The Cassiopeia Dwarf was found in 1998, together with the Pegasus Dwarf, by a team of astronomers (Karachentsev and Karachentseva) in Russia and Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv .... The Cassiopeia Dwarf and the Pegasus Dwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pegasus Dwarf Spheroidal Galaxy
The Pegasus Dwarf Spheroidal (also known as ''Andromeda VI'' or ''Peg dSph'' for short) is a dwarf spheroidal galaxy about 2.7 million light-years away in the constellation Pegasus. The Pegasus Dwarf is a member of the Local Group and a satellite galaxy of the Andromeda Galaxy (M31). General information The Pegasus Dwarf Spheroidal is a galaxy with mainly metal-poor stellar populations. Its metallicity is e/H≃ −1.3. It is located at the right ascension 23h51m46.30s and declination +24d34m57.0s in the equatorial coordinate system (epoch J2000.0), and in a distance of 820 ± 20 kpc from Earth and a distance of 294 ± 8 kpc from the Andromeda Galaxy. The galaxy was discovered in 1999 by various authors on the Second Palomar Observatory Sky Survey (POSS II) films. See also * List of Andromeda's satellite galaxies * Pegasus Dwarf Irregular Galaxy (Peg DIG) * Pegasus galaxy, the Stargate Atlantis ''Stargate Atlantis'' (usually stylized in all caps and often abbrev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
