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Sagittarius A*

Sagittarius A* (pronounced "Sagittarius A-star", standard abbreviation Sgr A*) is a bright and very compact astronomical radio source at the center of the Milky Way, near the border of the constellations Sagittarius and Scorpius. [1]

89 relations: Accretion disc, Active galactic nucleus, 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, Extinction (astronomy), Fermi Gamma-ray Space Telescope, Galactic Center, Galaxy, Gamma ray, GCIRS 13E, General relativity, Gravitational lens, Hawking radiation, INTEGRAL, Intermediate-mass black hole, Karl G. Jansky Very Large Array, 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 Radio Astronomy Observatory, Nature (journal), 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), Swift Gamma-Ray Burst Mission, The Astrophysical Journal, The New York Times, Very Large Telescope, Very-long-baseline interferometry, Visible spectrum, W. M. Keck Observatory, X-ray, X-ray astronomy, XMM-Newton. Expand index (39 more) »

Accretion disc

An accretion disc is a structure (often a circumstellar disk) formed by diffused material in orbital motion around a massive central body.

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Active galactic nucleus

An active galactic nucleus (AGN) is a compact region at the centre of a galaxy that has a much higher than normal luminosity over at least some portion – and possibly all – of the electromagnetic spectrum.

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Angular diameter

The angular diameter or apparent size is an angular measurement describing how large a sphere or circle appears from a given point of view.

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Apsis

The apsis (Greek ἁψίς), plural apsides (Greek: ἁψίδες) is an extreme point in an object's orbit.

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Asteroid

Asteroids are minor planets, especially those of the inner Solar System.

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Astronomical interferometer

An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution by means of interferometry.

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Astronomical radio source

Astronomical radio sources are objects in outer space that emit strong radio waves.

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Astronomical unit

The astronomical unit (symbol au, AU or ua) is a unit of length, roughly the distance from the Earth to the Sun.

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Astrophysical jet

An astrophysical jet (hereafter 'jet') is a phenomenon often seen in astronomy, where streams of matter are emitted along the axis of rotation of a compact object.

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Astrophysical maser

An astrophysical maser is a naturally occurring source of stimulated spectral line emission, typically in the microwave portion of the electromagnetic spectrum.

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Chandra X-ray Observatory

The Chandra X-ray Observatory (CXO), previously known as the Advanced X-ray Astrophysics Facility (AXAF), is a space observatory launched on STS-93 by NASA on July 23, 1999.

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Compact star

In astronomy, the term compact star (sometimes compact object) is used to refer collectively to white dwarfs, neutron stars, other exotic dense stars, and black holes.

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Declination

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.

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Degenerate matter

Degenerate matter in physics is a collection of free, non-interacting particles with a pressure and other physical characteristics determined by quantum mechanical effects.

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Ellipse

In mathematics, an ellipse is a curve on 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.

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Elliptical galaxy

An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile.

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Epoch (astronomy)

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.

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European Southern Observatory

The European Southern Observatory (ESO, formally: European Organisation for Astronomical Research in the Southern Hemisphere; Observatoire européen austral) is a 16-nation intergovernmental research organisation for astronomy.

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European Space Agency

The European Space Agency (ESA; Agence spatiale européenne, ASE; Europäische Weltraumorganisation) is an intergovernmental organisation dedicated to the exploration of space, with 22 member states.

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Extinction (astronomy)

Extinction is a term used in astronomy to describe the absorption and scattering of electromagnetic radiation by dust and gas between an emitting astronomical object and the observer.

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Fermi Gamma-ray Space Telescope

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.

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Galactic Center

The Galactic Center is the rotational center of the Milky Way.

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Galaxy

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas and dust, and dark matter.

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Gamma ray

Gamma radiation, also known as gamma rays, and denoted by the Greek letter γ, refers to electromagnetic radiation of an extremely high frequency and therefore consists of high-energy photons.

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GCIRS 13E

GCIRS 13E is potentially an intermediate mass black hole (IMBH) with a mass of about 1300 solar masses orbiting Sagittarius A* at a distance of about three light years.

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General relativity

General relativity, also known as the general theory of relativity, is the geometric theory of gravitation published by Albert Einstein in 1915 and the current description of gravitation in modern physics.

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Gravitational lens

A gravitational lens refers to a distribution of matter (such as a cluster of galaxies) between a distant source and an observer, that is capable of bending the light from the source, as it travels towards the observer.

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Hawking radiation

Hawking radiation is black body radiation that is predicted to be released by black holes, due to quantum effects near the event horizon.

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INTEGRAL

INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) is a currently operational space telescope for observing gamma rays.

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Intermediate-mass black hole

An intermediate-mass black hole (IMBH) is a hypothetical class of black hole with mass in the range 100 to one million solar masses: significantly more than stellar black holes but less than supermassive black holes.

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Karl G. Jansky Very Large Array

The Karl G. Jansky Very Large Array (VLA) is a radio astronomy observatory located on the Plains of San Agustin, between the towns of Magdalena and Datil, some 50 miles (80 km) west of Socorro, New Mexico.

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Kelvin

The kelvin is a unit of measure for temperature based upon an absolute scale.

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Kepler orbit

In celestial mechanics, a Kepler orbit (or Keplerian orbit) describes the motion of an orbiting body as an ellipse, parabola, or hyperbola, which forms a two-dimensional orbital plane in three-dimensional space.

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Kepler's laws of planetary motion

In astronomy, Kepler's laws of planetary motion are three scientific laws describing the motion of planets around the Sun.

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Kilometre

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 United Kingdom where the statute mile is the official unit used.

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Lawrence Livermore National Laboratory

Lawrence Livermore National Laboratory (LLNL) is a federal research facility in Livermore, California, founded by the University of California in 1952.

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Leonard–Merritt mass estimator

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.

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Light echo

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 phenomenon observed in astronomy.

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Light-second

A light-second is a unit of length useful in astronomy, telecommunications and relativistic physics.

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Light-year

A light-year (abbreviation: ly), sometimes written light year, is a unit of length used informally to express astronomical distances.

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Magnetar

A magnetar is a type of neutron star with an extremely powerful magnetic field.

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Magnetic field

A magnetic field is the magnetic effect of electric currents and magnetic materials.

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Magnitude (astronomy)

In astronomy, magnitude is the logarithmic measure of the brightness of an object, measured in a specific wavelength or passband, usually in the visible or near-infrared spectrum.

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Max Planck Institute for Extraterrestrial Physics

The Max Planck Institute for Extraterrestrial Physics is a Max Planck Institute, located in Garching, near Munich, Germany.

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Mercury (planet)

Mercury is the smallest and closest to the Sun of the eight planets in the Solar System, with an orbital period of about 88 Earth days.

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Micrometre

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 1×10−6 of a metre (SI standard prefix "micro-".

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Milky Way

The Milky Way is the galaxy that contains our Solar System.

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Millimetre

The millimetre (International spelling as used by the International Bureau of Weights and Measures) or millimeter (American spelling) (SI unit symbol mm) is a unit of length in the metric system, equal to one thousandth of a metre, which is the SI base unit of length.

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Minute and second of arc

A minute of arc (MOA), arcminute (arcmin) or minute arc is a unit of angular measurement equal to one-sixtieth of one degree.

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Molecular cloud

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).

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Monthly Notices of the Royal Astronomical Society

Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.

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NASA

The National Aeronautics and Space Administration (NASA) is the United States government agency responsible for the civilian space program as well as aeronautics and aerospace research.

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National Radio Astronomy Observatory

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.

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Nature (journal)

Nature is a British interdisciplinary scientific journal, first published on 4 November 1869.

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Orbital elements

Orbital elements are the parameters required to uniquely identify a specific orbit.

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Orbital period

The orbital period is the time taken for a given object to make one complete orbit around another object.

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Parsec

A parsec (symbol: pc) is a unit of length used to measure the astronomically large distances to objects outside the Solar System.

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Perihelion and aphelion

The perihelion is the point in the orbit of a planet, asteroid, comet or other star-orbiting body where it is nearest to its star.

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Proper motion

Proper motion is the astronomical measure of the observed changes in apparent positions of stars in the sky as seen from the center of mass of the Solar System, as compared to the imaginary fixed background of the more distant stars.

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Radiation pressure

Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation.

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Radio

Radio is the radiation (wireless transmission) of electromagnetic energy through space.

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Reinhard Genzel

Reinhard Genzel (born 24 March 1952 in Bad Homburg vor der Höhe, Germany) is a German astrophysicist.

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Right ascension

Right ascension (abbreviated RA; symbol α) is the angular distance measured eastward along the celestial equator from the vernal equinox to the hour circle of the point in question.

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S0–102

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.

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S2 (star)

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 and a pericenter distance of 17 light hours (18 Tm or 120 AU) — about four times the distance of Neptune from the Sun.

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Sagittarius (constellation)

Sagittarius is one of the constellations of the zodiac.

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Sagittarius A

Sagittarius A or Sgr A is a complex radio source at the center of the Milky Way.

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Sagittarius B2

Sagittarius B2 (Sgr B2) is a giant molecular cloud of gas and dust that is located about from the center of the Milky Way.

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Schwarzschild radius

The Schwarzschild radius (sometimes historically referred to as the gravitational radius) is the radius of a sphere such that, if all the mass of an object were to be compressed within that sphere, the escape velocity from the surface of the sphere would equal the speed of light.

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Scorpius

Scorpius is one of the constellations of the zodiac.

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Seyfert galaxy

Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars.

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SGR J1745-2900

PSR J1745-2900 is the first discovered magnetar, orbiting a black hole in the Sagittarius A* system.

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Solar mass

The solar mass is a standard unit of mass in astronomy that is used to indicate the masses of other stars, as well as clusters, nebulae and galaxies.

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Solar System

The Solar SystemCapitalization of the name varies.

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Spiral galaxy

A spiral galaxy is a certain kind of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae(pp. 124–151) and, as such, forms part of the Hubble sequence.

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Sun

The Sun (in Greek: Helios, in Latin: Sol) is the star at the center of the Solar System and is by far the most important source of energy for life on Earth.

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Supermassive black hole

A supermassive black hole (SMBH) is the largest type of black hole, on the order of hundreds of thousands to billions of solar masses, and is found in the center of almost all massive galaxies.

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Supernova remnant

A supernova remnant (SNR) is the structure resulting from the explosion of a star in a supernova.

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Suzaku (satellite)

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.

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Swift Gamma-Ray Burst Mission

The Swift Gamma-Ray Burst Mission consists of a robotic spacecraft called Swift, which was launched into orbit on November 20, 2004, at 17:16:00 UTC on a Delta II 7320-10C expendable launch vehicle.

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The Astrophysical Journal

The Astrophysical Journal, often abbreviated ApJ (pronounced "ap jay") in references and speech, is a peer-reviewed scientific journal of astrophysics, established in 1895 by American astronomers George Ellery Hale and James Edward Keeler.

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The New York Times

The New York Times (NYT) is an American daily newspaper, founded and continuously published in New York City since September 18, 1851, by the New York Times Company.

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Very Large Telescope

The Very Large Telescope (VLT) is a telescope operated by the European Southern Observatory on Cerro Paranal in the Atacama Desert of northern Chile.

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Very-long-baseline interferometry

Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy.

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Visible spectrum

The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye.

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W. M. Keck Observatory

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.

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X-ray

X-radiation (composed of X-rays) is a form of electromagnetic radiation.

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X-ray astronomy

X-ray astronomy is an observational branch of astronomy which deals with the study of X-ray observation and detection from astronomical objects.

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XMM-Newton

The XMM-Newton, also known as the X-ray Multi-Mirror Mission and the High Throughput X-ray Spectroscopy Mission, is an orbiting X-ray observatory launched by ESA in December 1999 on an Ariane 5 rocket.

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Redirects here:

Black Hole at the center of the Milky Way, Black Hole at the center of the galaxy, G2 gas cloud, Sag A*, Sagitarius A*, Sagittarius A *, Sagittarius A-star, Sgr A*, SgrA*.

References

[1] https://en.wikipedia.org/wiki/Sagittarius_A*

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