94 relations: Accretion disk, Active galactic nucleus, Andrea M. Ghez, Angular diameter, Apsis, Asteroid, Astronomical interferometer, Astronomical radio source, Astronomical unit, Astrophysical jet, Astrophysical maser, Chandra X-ray Observatory, Compact star, Declination, Degenerate matter, Ellipse, Elliptical galaxy, Epoch (astronomy), European Southern Observatory, European Space Agency, Event Horizon Telescope, Excited state, Extinction (astronomy), Fermi Gamma-ray Space Telescope, Galactic Center, Gamma ray, GCIRS 13E, General relativity, Gravitational lens, Hawking radiation, INTEGRAL, Intermediate-mass black hole, Karl Guthe Jansky, Kelvin, Kepler orbit, Kepler's laws of planetary motion, Kilometre, Lawrence Livermore National Laboratory, Leonard–Merritt mass estimator, Light echo, Light-second, Light-year, Magnetar, Magnetic field, Magnitude (astronomy), Max Planck Institute for Extraterrestrial Physics, Mercury (planet), Micrometre, Milky Way, Millimetre, ..., Minute and second of arc, Molecular cloud, Monthly Notices of the Royal Astronomical Society, NASA, National Geographic, National Radio Astronomy Observatory, Nature (journal), Neil Gehrels Swift Observatory, Orbital elements, Orbital period, Parsec, Perihelion and aphelion, Proper motion, Radiation pressure, Radio, Reinhard Genzel, Right ascension, S0–102, S2 (star), Sagittarius (constellation), Sagittarius A, Sagittarius B2, Schwarzschild radius, Scorpius, Seyfert galaxy, SGR J1745-2900, Solar mass, Solar System, Spiral galaxy, Sun, Supermassive black hole, Supernova remnant, Suzaku (satellite), The Astrophysical Journal, The New York Times, Theory of relativity, Very Large Array, Very Large Telescope, Very-long-baseline interferometry, Visible spectrum, W. M. Keck Observatory, X-ray, X-ray astronomy, XMM-Newton. Expand index (44 more) » « Shrink index
An accretion disk is a structure (often a circumstellar disk) formed by diffused material in orbital motion around a massive central body.
An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much higher than normal luminosity over at least some portion—and possibly all—of the electromagnetic spectrum, with characteristics indicating that the excess luminosity is not produced by stars.
Andrea Mia Ghez (born June 16, 1965) is an American astronomer and professor in the Department of Physics and Astronomy at UCLA.
The angular diameter, angular size, apparent diameter, or apparent size is an angular measurement describing how large a sphere or circle appears from a given point of view.
An apsis (ἁψίς; plural apsides, Greek: ἁψῖδες) is an extreme point in the orbit of an object.
Asteroids are minor planets, especially those of the inner Solar System.
An astronomical interferometer is an array of separate telescopes, mirror segments, or radio telescope antennas that work together as a single telescope to provide higher resolution images of astronomical objects such as stars, nebulas and galaxies by means of interferometry.
Astronomical radio sources are objects in outer space that emit strong radio waves.
The astronomical unit (symbol: au, ua, or AU) is a unit of length, roughly the distance from Earth to the Sun.
An astrophysical jet is an astronomical phenomenon where outflows of ionised matter are emitted as an extended beam along the axis of rotation.
An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum.
The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a Flagship-class space observatory launched on STS-93 by NASA on July 23, 1999.
In astronomy, the term "compact star" (or "compact object") refers collectively to white dwarfs, neutron stars, and black holes.
In astronomy, declination (abbreviated dec; symbol δ) is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle.
Degenerate matter is a highly dense state of matter in which particles must occupy high states of kinetic energy in order to satisfy the Pauli exclusion principle.
In mathematics, an ellipse is a curve in a plane surrounding two focal points such that the sum of the distances to the two focal points is constant for every point on the curve.
An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless image.
In astronomy, an epoch is a moment in time used as a reference point for some time-varying astronomical quantity, such as the celestial coordinates or elliptical orbital elements of a celestial body, because these are subject to perturbations and vary with time.
The European Southern Observatory (ESO) is a 15-nation intergovernmental research organization for ground-based astronomy.
The European Space Agency (ESA; Agence spatiale européenne, ASE; Europäische Weltraumorganisation) is an intergovernmental organisation of 22 member states dedicated to the exploration of space.
The Event Horizon Telescope (EHT) is a project to create a large telescope array consisting of a global network of radio telescopes and combining data from several very-long-baseline interferometry (VLBI) stations around the Earth.
In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum).
In astronomy, extinction is the absorption and scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observer.
The Fermi Gamma-ray Space Telescope (FGST), formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit.
The Galactic Center is the rotational center of the Milky Way.
A gamma ray or gamma radiation (symbol γ or \gamma), is penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei.
GCIRS 13E is an infrared and radio object near the galactic centre.
General relativity (GR, also known as the general theory of relativity or GTR) is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics.
A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer.
Hawking radiation is blackbody radiation that is predicted to be released by black holes, due to quantum effects near the event horizon.
INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) is a currently operational space telescope for observing gamma rays.
An intermediate-mass black hole (IMBH) is a class of black hole with mass in the range 102-105 solar masses: significantly more than stellar black holes but less than the 105-109 solar mass supermassive black holes.
Karl Guthe Jansky (October 22, 1905 – February 14, 1950) was an American physicist and radio engineer who in August 1931 first discovered radio waves emanating from the Milky Way.
The Kelvin scale is an absolute thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.
In celestial mechanics, a Kepler orbit (or Keplerian orbit) is the motion of one body relative to another, as an ellipse, parabola, or hyperbola, which forms a two-dimensional orbital plane in three-dimensional space.
In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.
The kilometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: km; or) or kilometer (American spelling) is a unit of length in the metric system, equal to one thousand metres (kilo- being the SI prefix for). It is now the measurement unit used officially for expressing distances between geographical places on land in most of the world; notable exceptions are the United States and the road network of the United Kingdom where the statute mile is the official unit used.
Lawrence Livermore National Laboratory (LLNL) is an American federal research facility in Livermore, California, United States, founded by the University of California, Berkeley in 1952.
The Leonard–Merritt mass estimator is a formula for estimating the mass of a spherical stellar system using the apparent (angular) positions and proper motions of its component stars.
Reflected light following path B arrives shortly after the direct flash following path A but before light following path C. B and C have the same apparent distance from the star as seen from Earth. A light echo is a physical phenomenon caused by light reflected off surfaces distant from the source, and arriving at the observer with a delay relative to this distance.
The light-second is a unit of length useful in astronomy, telecommunications and relativistic physics.
The light-year is a unit of length used to express astronomical distances and measures about 9.5 trillion kilometres or 5.9 trillion miles.
A magnetar is a type of neutron star with an extremely powerful inferred magnetic field (\sim 10^ - 10^ G).
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
In astronomy, magnitude is a logarithmic measure of the brightness of an object in a defined passband, often in the visible or infrared spectrum, but sometimes across all wavelengths.
The Max Planck Institute for Extraterrestrial Physics is a Max Planck Institute, located in Garching, near Munich, Germany.
Mercury is the smallest and innermost planet in the Solar System.
The micrometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is an SI derived unit of length equaling (SI standard prefix "micro-".
The Milky Way is the galaxy that contains our Solar System.
The millimetre (International spelling as used by the International Bureau of Weights and Measures; SI unit symbol mm) or millimeter (American spelling) is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length.
A minute of arc, arcminute (arcmin), arc minute, or minute arc is a unit of angular measurement equal to of one degree.
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H2).
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
The National Aeronautics and Space Administration (NASA) is an independent agency of the executive branch of the United States federal government responsible for the civilian space program, as well as aeronautics and aerospace research.
National Geographic (formerly the National Geographic Magazine and branded also as NAT GEO or) is the official magazine of the National Geographic Society.
The National Radio Astronomy Observatory (NRAO) is a Federally Funded Research and Development Center of the United States National Science Foundation operated under cooperative agreement by Associated Universities, Inc for the purpose of radio astronomy.
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
The Neil Gehrels Swift Observatory, previously called the Swift Gamma-Ray Burst Mission, is a NASA space telescope designed to detect gamma-ray bursts (GRBs).
Orbital elements are the parameters required to uniquely identify a specific orbit.
The orbital period is the time a given astronomical object takes to complete one orbit around another object, and applies in astronomy usually to planets or asteroids orbiting the Sun, moons orbiting planets, exoplanets orbiting other stars, or binary stars.
The parsec (symbol: pc) is a unit of length used to measure large distances to astronomical objects outside the Solar System.
The perihelion of any orbit of a celestial body about the Sun is the point where the body comes nearest to the Sun.
Proper motion is the astronomical measure of the observed changes in the apparent places of stars or other celestial objects in the sky, as seen from the center of mass of the Solar System, compared to the abstract background of the more distant stars.
Radiation pressure is the pressure exerted upon any surface due to the exchange of momentum between the object and the electromagnetic field.
Radio is the technology of using radio waves to carry information, such as sound, by systematically modulating properties of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width.
Reinhard Genzel (born 24 March 1952 in Bad Homburg vor der Höhe, Germany) is a German astrophysicist.
Right ascension (abbreviated RA; symbol) is the angular distance measured only eastward along the celestial equator from the Sun at the March equinox to the (hour circle of the) point above the earth in question.
S0–102 is a star that is located very close to the centre of the Milky Way, near the radio source Sagittarius A*, orbiting it with an orbital period of 11.5 years.
Source 2 (abbreviated S2), also known as S0–2, is a star that is located close to the radio source Sagittarius A*, orbiting it with an orbital period of 15.56 ± 0.35 years, a semi-major axis of about 970 AU, and a pericenter distance of 17 light hours (18 Tm or 120 AU)—an orbit with a period only about 30% longer than that of Jupiter around the Sun, but coming no closer than about four times the distance of Neptune from the Sun.
Sagittarius is one of the constellations of the zodiac.
Sagittarius A or Sgr A is a complex radio source at the center of the Milky Way.
Sagittarius B2 (Sgr B2) is a giant molecular cloud of gas and dust that is located about from the center of the Milky Way.
The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is a physical parameter that shows up in the Schwarzschild solution to Einstein's field equations, corresponding to the radius defining the event horizon of a Schwarzschild black hole.
Scorpius is one of the constellations of the zodiac.
Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars.
SGR J1745−2900 or PSR J1745-2900 is the first discovered magnetar, orbiting a black hole in the Sagittarius A* system.
The solar mass is a standard unit of mass in astronomy, equal to approximately.
The Solar SystemCapitalization of the name varies.
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae(pp. 124–151) and, as such, form part of the Hubble sequence.
The Sun is the star at the center of the Solar System.
A supermassive black hole (SMBH or SBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses, and is found in the centre of almost all currently known massive galaxies.
A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova.
Suzaku (formerly ASTRO-EII) was an X-ray astronomy satellite developed jointly by NASA's Goddard Space Flight Center and the Institute of Space and Aeronautical Science at JAXA to probe high energy X-ray sources, such as supernova explosions, black holes and galactic clusters.
The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics and astronomy, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.
The New York Times (sometimes abbreviated as The NYT or The Times) is an American newspaper based in New York City with worldwide influence and readership.
The theory of relativity usually encompasses two interrelated theories by Albert Einstein: special relativity and general relativity.
The Karl G. Jansky Very Large Array (VLA) is a centimeter-wavelength radio astronomy observatory located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro.
The Very Large Telescope (VLT) is a telescope facility operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile.
Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy.
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye.
The W. M. Keck Observatory is a two-telescope astronomical observatory at an elevation of 4,145 meters (13,600 ft) near the summit of Mauna Kea in the U.S. state of Hawaii.
X-rays make up X-radiation, a form of electromagnetic radiation.
X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects.
XMM-Newton, also known as the High Throughput X-ray Spectroscopy Mission and the X-ray Multi-Mirror Mission, is an X-ray space observatory launched by the European Space Agency in December 1999 on an Ariane 5 rocket.