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Lyman-alpha Blob
In astronomy, a Lyman-alpha blob (LAB) is a huge concentration of a gas emitting the Lyman-alpha emission line. LABs are some of the largest known individual objects in the Universe. Some of these gaseous structures are more than 400,000 light years across. So far they have only been found in the high-redshift universe because of the ultraviolet nature of the Lyman-alpha emission line. Since Earth's atmosphere is very effective at filtering out UV photons, the Lyman-alpha photons must be redshifted in order to be transmitted through the atmosphere. The most famous Lyman-alpha blobs were discovered in 2000 by Steidel et al. Matsuda et al., using the Subaru Telescope of the National Astronomical Observatory of Japan extended the search for LABs and found over 30 new LABs in the original field of Steidel et al., although they were all smaller than the originals. These LABs form a structure which is more than 200 million light-years in extent. It is currently unknown whether LABs ...
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Animation Of A Lyman-alpha Blob
Animation is a filmmaking technique whereby image, still images are manipulated to create Motion picture, moving images. In traditional animation, images are drawn or painted by hand on cel, transparent celluloid sheets to be photographed and exhibited on film. Animation has been recognised as an artistic medium, specifically within the Entertainment#Industry, entertainment industry. Many animations are either traditional animations or computer animations made with computer-generated imagery (CGI). Stop motion animation, in particular claymation, has continued to exist alongside these other forms. Animation is contrasted with live action, although the two do not exist in isolation. Many moviemakers have produced Live-action animation, films that are a hybrid of the two. As CGI increasingly Photorealism, approximates photographic imagery, filmmakers can easily Compositing, composite 3D animations into their film rather than using practical effects for showy visual effects (VFX). ...
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Lyman-alpha Blob LAB-1
Lyman-alpha, typically denoted by Ly-α or Lyα, is a spectral line of hydrogen (or, more generally, of any one-electron atom) in the Lyman series. It is emitted when the atomic electron transitions from an ''n'' = 2 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 UV (VUV), characterized by a strong absorption in the air. Fine structure The Lyman-alpha doublet. Because of the spin–orbit interaction, the Lyman-alpha line splits into a 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 perturbed Hamiltonian are labeled by the ''total'' angular momentum ''j'' of the electron, not just the or ...
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Lyman-alpha Blobs
Lyman-alpha, typically denoted by Ly-α or Lyα, 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 ...
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Newfound Blob (other)
Newfound Blob may refer to: * Lyman-alpha blob 1, Lyman-alpha blob 1 (LAB-1), one of the first discovered Lyman-alpha blobs * Himiko (Lyman-alpha blob) * EQ J221734.0+001701, the ''SSA22 Protocluster'' * a gas cloud orbiting Sagittarius A* * the magma plume causing the African superswell {{dab ...
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Lyman Break Galaxy
Lyman-break galaxies are star-forming galaxies at high redshift that are selected using the differing appearance of the galaxy in several imaging filters due to the position of the Lyman limit. The technique has primarily been used to select galaxies at redshifts of ''z'' = 3–4 using ultraviolet and optical filters, but progress in ultraviolet astronomy and in infrared astronomy has allowed the use of this technique at lower and higher redshifts using ultraviolet and near-infrared filters. The Lyman-break galaxy selection technique relies upon the fact that radiation at higher energies than the Lyman limit at 912  Å is almost completely absorbed by neutral gas around star-forming regions of galaxies. In the rest frame of the emitting galaxy, the emitted spectrum is bright at wavelengths longer than 912 Å, but very dim or imperceptible at shorter wavelengths. This is known as a " dropout", or "break", and can be used to find the position of the Lyman lim ...
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Lyman-alpha Emitter
A Lyman-alpha emitter (LAE) is a type of distant galaxy that emits Lyman-alpha radiation from neutral hydrogen. Most known LAEs are extremely distant, and because of the finite travel time of light they provide glimpses into the history of the universe. They are thought to be the progenitors of most modern Milky Way type galaxies. These galaxies can be found nowadays rather easily in narrow-band searches by an excess of their narrow-band flux at a wavelength which may be interpreted from their redshift : 1+z=\frac where z is the redshift, \lambda is the observed wavelength, and 1215.67 Å is the wavelength of Lyman-alpha emission. The Lyman-alpha line in most LAEs is thought to be caused by recombination of interstellar hydrogen that is ionized by an ongoing burst of star formation. Such Lyman alpha emission was first suggested as a signature of young galaxies by Bruce Partridge and P. J. E. Peebles in 1967. Experimental observations of the redshift of LAEs are importa ...
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Lyman-alpha Forest
In astronomical spectroscopy, the Lyman-alpha forest is a series of absorption lines in the spectra of distant galaxies and quasars arising from the Lyman-alpha electron transition of the neutral hydrogen atom. As the light travels through multiple gas clouds with different redshifts, multiple absorption lines are formed. History The Lyman-alpha forest was first discovered in 1970 by astronomer Roger Lynds in an observation of the quasar 4C 05.34. Quasar 4C 05.34 was the farthest object observed to that date, and Lynds noted an unusually large number of absorption lines in its spectrum and suggested that most of the absorption lines were all due to the same Lyman-alpha transition. Follow-up observations by John Bahcall and Samuel Goldsmith confirmed the presence of the unusual absorption lines, though they were less conclusive about the origin of the lines. Subsequently, the spectra of many other high-redshift quasars were observed to have the same system of narrow absorption ...
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Green Bean Galaxy
Green bean galaxies (GBGs) are very rare astronomical objects that are thought to be quasar ionization echos. They were discovered by Mischa Schirmer and colleagues R. Diaz, K. Holhjem, N.A. Levenson, and C. Winge. The authors report the discovery of a sample of Seyfert-2 galaxies with ultra-luminous galaxy-wide narrow-line regions (NLRs) at redshifts z=0.2–0.6. While examining survey images taken with the 3.6-meter Canada–France–Hawaii Telescope (CFHT) atop 4200-m Mauna Kea, Hawaii, Schirmer noticed a galaxy with unusual colors—strongly peaking in the r filter, suggesting a spectral line. In fact, the color is quite similar to the Green Pea galaxies (GPs), which are compact star-forming galaxies. However, the object which became known as a GBG is much larger. These galaxies are so rare that there is on average only one in a cube about 1.3 billion light-years across. They were nicknamed GBGs because of their color and because they are superficially similar to, but larg ...
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Galaxy Filament
In cosmology, galaxy filaments are the largest known structures in the universe, consisting of walls of galactic superclusters. These massive, thread-like formations can commonly reach 50 to 80 megaparsecs ()—with the largest found to date being the Hercules-Corona Borealis Great Wall at around in length—and form the boundaries between voids. Due to the accelerating expansion of the universe, the individual clusters of gravitationally bound galaxies that make up galaxy filaments are moving away from each other at an accelerated rate; in the far future they will dissolve. Galaxy filaments form the cosmic web and define the overall structure of the observable universe. Discovery Discovery of structures larger than superclusters began in the late 1980s. In 1987, astronomer R. Brent Tully of the University of Hawaii's Institute of Astronomy identified what he called the Pisces–Cetus Supercluster Complex. The CfA2 Great Wall was discovered in 1989, followed by the Sloa ...
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Damped Lyman-alpha System
Damped Lyman alpha systems or Damped Lyman alpha absorption systems is a term used by astronomers for concentrations of neutral hydrogen gas that are detected in the spectra of quasars – a class of distant Active Galactic Nuclei. They are defined to be systems where the column density (density projected along the line of sight to the quasar) of hydrogen is larger than 2 x 1020 atoms/cm2. The observed spectra consist of neutral hydrogen Lyman alpha absorption lines which are broadened by radiation damping. These systems can be observed in quantity at relatively high redshifts of 2–4, when they contained most of the neutral hydrogen in the universe. They are believed to be associated with the early stages of galaxy formation, as the high neutral hydrogen column densities of DLAs are also typical of sightlines in the Milky Way The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance ...
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List Of Most Massive Black Holes
This is an ordered list of the most massive black holes so far discovered (and probable candidates), measured in units of solar masses (), approximately . Introduction A supermassive black hole (SMBH) is an extremely large black hole, on the order of hundreds of thousands to tens of billions of solar masses (), and is theorized to exist in the center of almost all massive galaxies. In some galaxies, there are even binary systems of supermassive black holes (see the OJ 287 system.) Unambiguous dynamical evidence for SMBHs exists only in a handful of galaxies; these include the Milky Way, the Local Group galaxies M31 and M32, and a few galaxies beyond the Local Group, e.g. NGC 4395. In these galaxies, the mean square (or root mean square) velocities of the stars or gas rises as ~1/r near the center, indicating a central point mass. In all other galaxies observed to date, the rms velocities are flat, or even falling, toward the center, making it impossible to state with cer ...
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