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Multi-unit Spectroscopic Explorer
The multi-unit spectroscopic explorer (MUSE) is an integral field spectrograph installed at the Very Large Telescope (VLT) of the European Southern Observatory (ESO). It operates in the visible wavelength range, and combines a wide field of view with a fine spatial sampling and a large simultaneous spectral range. It is designed to take advantage of the improved spatial resolution provided by adaptive optics. MUSE had first light on the VLT on 31 January 2014. 6. These sources can be extremely faint, in which case they can only be detected using through the emission in the Lyman-alpha emission line, such galaxies are frequently referred to as Lyman-alpha emitters. A common way to study such sources is to use narrow-band imaging, but this technique can only survey a very narrow redshift range at a time – set by the width of the filter. In addition this method is not as sensitive as direct spectroscopic studies because the width of the filter is wider than the typical width of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MUSE On Nasmyth Side View
In ancient Greek religion and mythology, the Muses ( grc, Μοῦσαι, Moûsai, el, Μούσες, Múses) are the inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in the poetry, lyric songs, and myths that were related orally for centuries in ancient Greek culture. Melete, Aoede, and Mneme are the original Boeotian Muses, and Calliope, Clio, Erato, Euterpe, Melpomene, Polyhymnia, Terpsichore, Thalia, and Urania are the nine Olympian Muses. In modern figurative usage, a Muse may be a source of artistic inspiration. Etymology The word ''Muses'' ( grc, Μοῦσαι, Moûsai) perhaps came from the o-grade of the Proto-Indo-European root (the basic meaning of which is 'put in mind' in verb formations with transitive function and 'have in mind' in those with intransitive function), or from root ('to tower, mountain') since all the most important cult-centres of the Muses were on mountains or hills. R. S. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lyman-alpha Line
The Lyman-alpha line, typically denoted by Ly-α, is a spectral line of hydrogen (or, more generally, of any Hydrogen-like atom, one-electron atom) in the Lyman series. It is emitted when the atomic electron transitions from an ''n'' = 2 atomic orbital, orbital to the ground state (''n'' = 1), where ''n'' is the principal quantum number. In hydrogen, its wavelength of 1215.67 angstroms ( or ), corresponding to a frequency of about , places Lyman-alpha in the ultraviolet (UV) part of the electromagnetic spectrum. More specifically, Ly-α lies in vacuum ultraviolet, vacuum UV (VUV), characterized by a strong absorption in the air. Fine structure image:Hydrogen fine structure2.svg, The Lyman-alpha doublet. Because of the spin–orbit interaction, the Lyman-alpha line splits into a fine structure, fine-structure doublet with the wavelengths of 1215.668 and 1215.674 angstroms. These components are called Ly-α3/2 and Ly-α1/2, respectively. The eigenstates of the Per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromatic Aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wavelength of light. The refractive index of most transparent materials decreases with increasing wavelength. Since the focal length of a lens depends on the refractive index, this variation in refractive index affects focusing. Chromatic aberration manifests itself as "fringes" of color along boundaries that separate dark and bright parts of the image. Types There are two types of chromatic aberration: ''axial'' (''longitudinal''), and ''transverse'' (''lateral''). Axial aberration occurs when different wavelengths of light are focused at different distances from the lens (focus ''shift''). Longitudinal aberration is typical at long focal lengths. Transverse aberration occurs when different wavelengths are focused at different positions i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Field Spectrograph
Integral Field Spectrographs (IFS) combine spectrographic and imaging capabilities in the optical or infrared wavelength domains -from 0.32 μm to 24 μm- to get from a single exposure spatially resolved spectra in a bi-dimensional region. Developed at first for the study of astronomical objects, this technique is now also used in many other fields, e.g. bio-medical science and Earth remote sensing, usually under the name of snapshot hyperspectral imaging. Rationale With the notable exception of individual stars, most astronomical objects are spatially resolved by large telescopes igure JWST moderately deep exposure For spectroscopic studies, the optimum would then be to get a spectrum for each spatial pixel (often call a spaxel in the IFS jargon) in the instrument field of view, getting full information on each target. This is loosely called a datacube from its two spatial and one spectral dimensions. Since both Visible Charge-Coupled Devices (CCD) and Infrared Detector Arrays ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muse The Medusa
In ancient Greek religion and mythology, the Muses ( grc, Μοῦσαι, Moûsai, el, Μούσες, Múses) are the inspirational goddesses of literature, science, and the arts. They were considered the source of the knowledge embodied in the poetry, lyric songs, and myths that were related orally for centuries in ancient Greek culture. Melete, Aoede, and Mneme are the original Boeotian Muses, and Calliope, Clio, Erato, Euterpe, Melpomene, Polyhymnia, Terpsichore, Thalia, and Urania are the nine Olympian Muses. In modern figurative usage, a Muse may be a source of artistic inspiration. Etymology The word ''Muses'' ( grc, Μοῦσαι, Moûsai) perhaps came from the o-grade of the Proto-Indo-European root (the basic meaning of which is 'put in mind' in verb formations with transitive function and 'have in mind' in those with intransitive function), or from root ('to tower, mountain') since all the most important cult-centres of the Muses were on mountains or hills. R. S. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Titan (moon)
Titan is the largest moon of Saturn and the second-largest natural satellite in the Solar System. It is the only moon known to have a dense atmosphere, and is the only known object in space other than Earth on which clear evidence of stable bodies of surface liquid has been found. Titan is one of the seven gravitationally rounded moons in orbit around Saturn, and the second most distant from Saturn of those seven. Frequently described as a planet-like moon, Titan is 50% larger (in diameter) than Earth's Moon and 80% more massive. It is the second-largest moon in the Solar System after Jupiter's moon Ganymede, and is larger than the planet Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn, and the sixth known planetary satellite (after Earth's moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii. From Titan's surface, Saturn subtends an arc of 5.09 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Io (moon)
Io (), or Jupiter I, is the innermost and third-largest of the four Galilean moons of the planet Jupiter. Slightly larger than Earth’s moon, Io is the fourth-largest moon in the Solar System, has the highest density of any moon, the strongest surface gravity of any moon, and the lowest amount of water (by atomic ratio) of any known astronomical object in the Solar System. It was discovered in 1610 by Galileo Galilei and was named after the mythological character Io, a priestess of Hera who became one of Zeus's lovers. With over 400 active volcanoes, Io is the most geologically active object in the Solar System. This extreme geologic activity is the result of tidal heating from friction generated within Io's interior as it is pulled between Jupiter and the other Galilean moons—Europa, Ganymede and Callisto. Several volcanoes produce plumes of sulfur and sulfur dioxide that climb as high as above the surface. Io's surface is also dotted with more than 100 mountains that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coma Cluster
The Coma Cluster (Abell 1656) is a large galaxy cluster, cluster of galaxies that contains over 1,000 identified galaxies. Along with the Leo Cluster (Abell 1367), it is one of the two major clusters comprising the Coma Supercluster. It is located in and takes its name from the constellation Coma Berenices. The cluster's mean distance from Earth is 99 Parsec, Mpc (321 million light years). Its ten brightest spiral galaxies have apparent magnitudes of 12–14 that are observable with amateur telescopes larger than 20 cm. The central region is dominated by two supergiant elliptical galaxy, elliptical galaxies: NGC 4874 and NGC 4889. The cluster is within a few degrees of the north galactic pole on the sky. Most of the galaxies that inhabit the central portion of the Coma Cluster are ellipticals. Both dwarf and giant ellipticals are found in abundance in the Coma Cluster. Cluster members As is usual for clusters of this richness, the galaxies are overwhelmingly ellipt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgo Cluster
The Virgo Cluster is a large cluster of galaxies whose center is 53.8 ± 0.3 Mly (16.5 ± 0.1 Mpc) away in the constellation Virgo. Comprising approximately 1,300 (and possibly up to 2,000) member galaxies, the cluster forms the heart of the larger Virgo Supercluster, of which the Local Group (containing our Milky Way galaxy) is a member. The Local Group actually experiences the mass of the Virgo Supercluster as the Virgocentric flow. It is estimated that the Virgo Cluster's mass is 1.2 out to 8 degrees of the cluster's center or a radius of about 2.2 Mpc. Many of the brighter galaxies in this cluster, including the giant elliptical galaxy Messier 87, were discovered in the late 1770s and early 1780s and subsequently included in Charles Messier's catalogue of non-cometary fuzzy objects. Described by Messier as nebulae without stars, their true nature was not recognized until the 1920s. The cluster subtends a maximum arc of approximately 8 degrees centered in the constellation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphere Of Influence (black Hole)
The sphere of influence is a region around a supermassive black hole in which the gravitational potential of the black hole dominates the gravitational potential of the host galaxy. The radius of the sphere of influence is called the "(gravitational) influence radius". There are two definitions in common use for the radius of the sphere of influence. The first is given by r_h = \frac where MBH is the mass of the black hole, ''σ'' is the stellar velocity dispersion of the host bulge, and ''G'' is the gravitational constant. The second definition is the radius at which the enclosed mass in stars equals twice MBH, i.e. M_\star(r [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supermassive Black Hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions of times the mass of the Sun (). Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, not even light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its Central massive object, center. For example, the Milky Way has a Galactic Center#Supermassive black hole, supermassive black hole in its Galactic Center, corresponding to the Astronomical radio source, radio source Sagittarius A*. Accretion (astrophysics), Accretion of Interstellar medium, interstellar gas onto supermassive black holes is the process responsible for powering Active galactic nucleus, active galactic nuclei (AGNs) and quasars. Two supermassive black holes have been directly imaged by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Supermassive Black Hole
A supermassive black hole (SMBH or sometimes SBH) is the largest type of black hole, with its mass being on the order of hundreds of thousands, or millions to billions of times the mass of the Sun (). Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, not even light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its Central massive object, center. For example, the Milky Way has a Galactic Center#Supermassive black hole, supermassive black hole in its Galactic Center, corresponding to the Astronomical radio source, radio source Sagittarius A*. Accretion (astrophysics), Accretion of Interstellar medium, interstellar gas onto supermassive black holes is the process responsible for powering Active galactic nucleus, active galactic nuclei (AGNs) and quasars. Two supermassive black holes have been directly imaged by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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