|
SDSS J0927 2943
SDSS J0927+2943 (SDSS J092712.65+294344.0) is an unusual quasar. It exhibits two sets of optical emission lines with different redshifts. The origin of the two emission line systems is believed to be a gravitational wave recoil event: the ejection of a supermassive black hole from the center of the host galaxy. In this interpretation, one of the emission line systems originates in gas that is bound to the black hole, while the other set is associated with gas that remains in the galaxy. Evidence for a recoiling black hole A team led by Stefanie Komossa of the Max Planck Institute for Extraterrestrial Physics carried out the analysis. Two systems of strong emission lines were identified in the optical spectrum A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of co ... of this quasar. The fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J2000
In astronomy, an epoch or reference epoch is a moment in time used as a reference point for some time-varying astronomical quantity. It is useful for the celestial coordinates or orbital elements of a celestial body, as they are subject to perturbations and vary with time. These time-varying astronomical quantities might include, for example, the mean longitude or mean anomaly of a body, the node of its orbit relative to a reference plane, the direction of the apogee or aphelion of its orbit, or the size of the major axis of its orbit. The main use of astronomical quantities specified in this way is to calculate other relevant parameters of motion, in order to predict future positions and velocities. The applied tools of the disciplines of celestial mechanics or its subfield orbital mechanics (for predicting orbital paths and positions for bodies in motion under the gravitational effects of other bodies) can be used to generate an ephemeris, a table of values giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GALEX
Galaxy Evolution Explorer (GALEX or Explorer 83 or SMEX-7) was a NASA orbiting space telescope designed to observe the universe in ultraviolet wavelengths to measure the history of star formation in the universe. In addition to paving the way for future ultraviolet missions, the space telescope allowed astronomers to uncover mysteries about the early universe and how it evolved, as well as better characterize phenomena like black holes and dark matter. The mission was extended three times over a period of 10 years before it was decommissioned in June 2013. GALEX was launched on 28 April 2003 and decommissioned in June 2013. Spacecraft The spacecraft was three-axis stabilized, with power coming from four fixed solar panels. The satellite bus is from Orbital Sciences Corporation based on OrbView 4. The telescope was a Modified Ritchey–Chrétien with a rotating grism. GALEX used the first ever UV light dichroic beam-splitter flown in space to direct photons to the Near ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quasar
A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous Accretion disk, accretion disc. Gas in the disc falling towards the black hole heats up and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosity, luminosities thousands of times greater than that of a galaxy such as the Milky Way. Quasars are usually categorized as a subclass of the more general category of AGN. The redshifts of quasars are of Expansion of the universe, cosmological origin. The term originated as a Contraction (grammar), contraction of "quasi-stellar ''[star-like]'' radio source"—because they were first identified during the 1950s as sources of radio-wave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emission Line
A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum. It may result from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible. Types of line spectra Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy (which is connected to its frequency) to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing orbitals), the photon is absorbed. Then the energy will be spontaneously re-emitted, either as one photon at the same f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Redshift
In physics, a redshift is an increase in the wavelength, and corresponding decrease in the frequency and photon energy, of electromagnetic radiation (such as light). The opposite change, a decrease in wavelength and increase in frequency and energy, is known as a #Blueshift, blueshift. The terms derive from the colours red and blue which form the extremes of the Visible spectrum, visible light spectrum. Three forms of redshift occur in astronomy and cosmology: Doppler effect, Doppler redshifts due to the relative motions of radiation sources, gravitational redshift as radiation escapes from gravitational potentials, and cosmological redshifts of all light sources proportional to their distances from Earth, a fact known as Hubble's law that implies the expansion of the universe, universe is expanding. All redshifts can be understood under the umbrella of Frame of reference, frame transformation laws. Gravitational waves, which also travel at Speed of light, the speed of light, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Wave
Gravitational waves are oscillations of the gravitational field that Wave propagation, travel through space at the speed of light; they are generated by the relative motion of gravity, gravitating masses. They were proposed by Oliver Heaviside in 1893 and then later by Henri Poincaré in 1905 as the gravitational equivalent of Electromagnetic radiation, electromagnetic waves. In 1916, Albert Einstein demonstrated that gravitational waves result from his general theory of relativity as ripples in spacetime. Gravitational waves transport energy as gravitational radiation, a form of radiant energy similar to electromagnetic radiation. Newton's law of universal gravitation, part of classical mechanics, does not provide for their existence, instead asserting that gravity has instantaneous effect everywhere. Gravitational waves therefore stand as an important relativistic phenomenon that is absent from Newtonian physics. Gravitational-wave astronomy has the advantage that, unlike elec ... [...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, including light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center. For example, the Milky Way galaxy has a supermassive black hole at its center, corresponding to the radio source Sagittarius A*. Accretion of interstellar gas onto supermassive black holes is the process responsible for powering active galactic nuclei (AGNs) and quasars. Two supermassive black holes have been directly imaged by the Event Horizon Telescope: the black hole in the giant elliptical galaxy Messier 87 and the black hole at the Milky Way's center (Sagittarius A*). Descr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Max Planck Institute For Extraterrestrial Physics
The Max Planck Institute for Extraterrestrial Physics is part of the Max Planck Society, located in Garching, near Munich, Germany. In 1991 the Max Planck Institute for Physics and Astrophysics split up into the Max Planck Institute for Extraterrestrial Physics, the Max Planck Institute for Physics and the Max Planck Institute for Astrophysics. The Max Planck Institute for Extraterrestrial Physics was founded as sub-institute in 1963. The scientific activities of the institute are mostly devoted to astrophysics with telescopes orbiting in space. A large amount of the resources are spent for studying black holes in the Milky Way Galaxy and in the remote universe. History The Max-Planck-Institute for extraterrestrial physics (MPE) was preceded by the department for extraterrestrial physics in the Max-Planck-Institute for physics and astrophysics. This department was established by Professor Reimar Lüst on October 23, 1961. A Max-Planck Senate resolution transformed this departm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectrum
A spectrum (: spectra or spectrums) is a set of related ideas, objects, or properties whose features overlap such that they blend to form a continuum. The word ''spectrum'' was first used scientifically in optics to describe the rainbow of colors in visible light after passing through a prism. In the optical spectrum, light wavelength is viewed as continuous, and spectral colors are seen to blend into one another smoothly when organized in order of their corresponding wavelengths. As scientific understanding of light advanced, the term came to apply to the entire electromagnetic spectrum, including radiation not visible to the human eye. ''Spectrum'' has since been applied by analogy to topics outside optics. Thus, one might talk about the " spectrum of political opinion", or the "spectrum of activity" of a drug, or the " autism spectrum". In these uses, values within a spectrum may not be associated with precisely quantifiable numbers or definitions. Such uses imply a bro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doubly Ionized Oxygen
In astronomy and atomic physics, doubly ionized oxygen is the ion O2+ (O III in spectroscopic notation). Ion Its emission forbidden lines in the visible spectrum fall primarily at the wavelength 500.7 nm, and secondarily at 495.9 nm. Before spectra of oxygen ions became known, these lines once led to a spurious identification of the substance as a new chemical element. Concentrated levels of O III are found in diffuse and planetary nebulae. Consequently, narrow band-pass filters that isolate the 500.7 nm and 495.9 nm wavelengths of light, that correspond to green- turquoise-cyan spectral colors, are useful in observing these objects, causing them to appear at higher contrast against the filtered and consequently blacker background of space (and possibly light-polluted terrestrial atmosphere) where the frequencies of IIIare much less pronounced. These emission lines were first discovered in the spectra of planetary nebulae in the 1860s. At that time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naked Quasar
HE0450-2958 is an unusual quasar. It has been called the "naked quasar" and the "quasar without a home" because it appears to lack a host galaxy. It is estimated to lie approximately one billion parsecs away. History A team of researchers led by Pierre Magain of the University of Liège, Belgium announced their findings in the September 14, 2005 issue of the journal ''Nature''.Magain, P. et al. (2005) Discovery of a bright quasar without a massive host galaxy ''Nature'', 437, 381 The quasar lies close in the sky to a disturbed, starburst galaxy (see figure, upper left). However, no galaxy was seen around the quasar itself (figure, middle), leading the authors to speculate One might suggest that the host galaxy has disappeared from our view as a result of the collision hich formed the disturbed galaxy but it is hard to imagine how the complete disruption of a galaxy could happen. In order for the quasar's host galaxy to have escaped detection, Magain et al. estimated that it w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quasars
A quasar ( ) is an extremely Luminosity, luminous active galactic nucleus (AGN). It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black hole with a mass ranging from millions to tens of billions of solar masses, surrounded by a gaseous Accretion disk, accretion disc. Gas in the disc falling towards the black hole heats up and releases energy in the form of electromagnetic radiation. The radiant energy of quasars is enormous; the most powerful quasars have luminosity, luminosities thousands of times greater than that of a galaxy such as the Milky Way. Quasars are usually categorized as a subclass of the more general category of AGN. The redshifts of quasars are of Expansion of the universe, cosmological origin. The term originated as a Contraction (grammar), contraction of "quasi-stellar ''[star-like]'' radio source"—because they were first identified during the 1950s as sources of radio-wave ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
