122 relations: Active galactic nucleus, Andromeda–Milky Way collision, Anemic galaxy, Astronomical object, Astronomy, Astrophysics, Atlas of Peculiar Galaxies, Barred irregular galaxy, Barred lenticular galaxy, Barred spiral galaxy, Blazar, Brightest cluster galaxy, Bulge (astronomy), Carina–Sagittarius Arm, Catalogue of Galaxies and Clusters of Galaxies, Cosmology, Cosmos Redshift 7, Dark galaxy, Dark matter halo, David Dunlap Observatory Catalogue, Disc galaxy, Dwarf elliptical galaxy, Dwarf galaxy, Dwarf spheroidal galaxy, Dwarf spiral galaxy, Edwin Hubble, Elliptical galaxy, Extragalactic astronomy, Faint blue galaxy, Field galaxy, Flocculent spiral galaxy, Galactic astronomy, Galactic Center, Galactic coordinate system, Galactic corona, Galactic Disc, Galactic habitable zone, Galactic halo, Galactic orientation, Galactic plane, Galactic quadrant, Galactic ridge, Galactic tide, Galactic year, Galaxy, Galaxy cluster, Galaxy color–magnitude diagram, Galaxy filament, Galaxy formation and evolution, Galaxy group, ..., Galaxy groups and clusters, Galaxy merger, Galaxy morphological classification, Galaxy rotation curve, Galileo Galilei, Grand design spiral galaxy, Hot, dust-obscured galaxy, Hubble's law, Illustris project, Interacting galaxy, Intergalactic dust, Intergalactic star, Intergalactic travel, Intermediate spiral galaxy, Interstellar medium, Irregular galaxy, Jellyfish galaxy, Lenticular galaxy, List of galaxies, List of galaxies named after people, List of galaxy groups and clusters, List of nearest galaxies, List of polar-ring galaxies, List of quasars, List of ring galaxies, List of spiral galaxies, List of voids, Lists of galaxies, Local Group, Low-ionization nuclear emission-line region, Low-surface-brightness galaxy, Luminous infrared galaxy, Lyman-alpha emitter, Lyon-Meudon Extragalactic Database, Magellanic spiral, Markarian galaxies, Milky Way, Morphological Catalogue of Galaxies, Multiwavelength Atlas of Galaxies, Norma Arm, Orion Arm, Outline (list), Pea galaxy, Peculiar galaxy, Perseus Arm, Physical cosmology, Polar-ring galaxy, Principal Galaxies Catalogue, Protogalaxy, Quasar, Radio galaxy, Ring galaxy, Sagittarius A*, Satellite galaxy, Scutum–Centaurus Arm, Seyfert galaxy, Shapley-Ames Catalog, Spiral galaxy, Starburst galaxy, Supercluster, Supermassive black hole, Type-cD galaxy, Ultra diffuse galaxy, Unbarred lenticular galaxy, Unbarred spiral galaxy, University of Ottawa, University of St Andrews, Uppsala General Catalogue, Void (astronomy), Void galaxy, Vorontsov-Vel'yaminov Interacting Galaxies, X-shaped radio galaxy. Expand index (72 more) » « Shrink index
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.
The Andromeda–Milky Way collision is a galactic collision predicted to occur in about 4 billion years between two galaxies in the Local Group—the Milky Way (which contains the Solar System and Earth) and the Andromeda Galaxy.
An anemic galaxy is a type of spiral galaxy characterized by a low contrast between its spiral arms and its disk.
An astronomical object or celestial object is a naturally occurring physical entity, association, or structure that exists in the observable universe.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
Astrophysics is the branch of astronomy that employs the principles of physics and chemistry "to ascertain the nature of the astronomical objects, rather than their positions or motions in space".
The Atlas of Peculiar Galaxies is a catalog of peculiar galaxies produced by Halton Arp in 1966.
A barred irregular galaxy is an irregular version of a barred spiral galaxy.
A barred lenticular galaxy is a lenticular version of a barred spiral galaxy.
A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars.
A blazar is a very compact quasar (quasi-stellar radio source) associated with a presumed supermassive black hole at the center of an active, giant elliptical galaxy.
A brightest cluster galaxy (BCG) is defined as the brightest galaxy in a cluster of galaxies.
In astronomy, a bulge is a tightly packed group of stars within a larger formation.
The Carina–Sagittarius Arm (also known as Sagittarius Arm or Sagittarius–Carina Arm, labeled -I) is generally thought to be a minor spiral arm of the Milky Way galaxy.
The Catalogue of Galaxies and of Clusters of Galaxies (pr CGCG) was compiled by Fritz Zwicky in 1961–68.
Cosmology (from the Greek κόσμος, kosmos "world" and -λογία, -logia "study of") is the study of the origin, evolution, and eventual fate of the universe.
Cosmos Redshift 7 (also known as COSMOS Redshift 7, Galaxy Cosmos Redshift 7, Galaxy CR7 or CR7) is a high-redshift Lyman-alpha emitter galaxy (meaning CR7 is one of the oldest, most distant galaxies), in the constellation Sextans, about 12.9 billion light travel distance years from Earth, reported to contain the first stars (first generation; Population III)—formed soon after the Big Bang during the reionisation epoch (redshift, z ∼ 6−7), when the Universe was about 800 million years old—to have provided the chemical elements (like oxygen, nitrogen, carbon, calcium and iron) needed for the later formation of planets and life as it is known.
A dark galaxy is a hypothesized galaxy with no, or very few, stars.
A dark matter halo is a hypothetical component of a galaxy that envelops the galactic disc and extends well beyond the edge of the visible galaxy.
David Dunlap Observatory Catalogue, known as the DDO or A Catalogue of Dwarf Galaxies, is a catalogue of dwarf galaxies that was published in 1959 (and later expanded in 1966) by Sidney van den Bergh.
A disc galaxy is a galaxy characterized by a disc, a flattened circular volume of stars.
Dwarf elliptical galaxies, or dEs, are elliptical galaxies that are smaller than ordinary elliptical galaxies.
A dwarf galaxy is a small galaxy composed of about 100 million up to several billion stars, a small number compared to the Milky Way's 200–400 billion stars.
A dwarf spheroidal galaxy (dSph) is a term in astronomy applied to small, low-luminosity galaxies with very little dust and an older stellar population.
A dwarf spiral galaxy is the dwarf version of a spiral galaxy.
Edwin Powell Hubble (November 20, 1889 – September 28, 1953) was an American astronomer.
An elliptical galaxy is a type of galaxy having an approximately ellipsoidal shape and a smooth, nearly featureless image.
Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way galaxy.
The faint blue galaxy (F.B.G.) problem in astrophysics first arose with observations starting in 1978 that there were more galaxies with a bolometric magnitude > 22 than then-current theory predicted.
A field galaxy is a galaxy that does not belong to a larger cluster of galaxies and hence is gravitationally alone.
A flocculent spiral galaxy is a type of spiral galaxy.
Galactic astronomy is the study of the Milky Way galaxy and all its contents.
The Galactic Center is the rotational center of the Milky Way.
The galactic coordinate system is a celestial coordinate system in spherical coordinates, with the Sun as its center, the primary direction aligned with the approximate center of the Milky Way galaxy, and the fundamental plane parallel to an approximation of the galactic plane but offset to its north.
The terms galactic corona and gaseous corona have been used in the first decade of the 21st century to describe a hot, ionised, gaseous component in the Galactic halo of the Milky Way.
The Galactic Disc is a component of disc galaxies, such as spiral galaxies and lenticular galaxies.
In astrobiology and planetary astrophysics, the galactic habitable zone is the region of a galaxy in which life might most likely develop.
A galactic halo is an extended, roughly spherical component of a galaxy which extends beyond the main, visible component.
Galactic clusters are gravitationally bound large-scale structures of multiple galaxies.
The galactic plane is the plane on which the majority of a disk-shaped galaxy's mass lies.
A galactic quadrant, or quadrant of the Galaxy, is one of four circular sectors in the division of the Milky Way Galaxy.
The galactic ridge is a region of the inner galaxy that is coincident with the galactic plane of the Milky Way.
A galactic tide is a tidal force experienced by objects subject to the gravitational field of a galaxy such as the Milky Way.
The galactic year, also known as a cosmic year, is the duration of time required for the Sun to orbit once around the center of the Milky Way Galaxy.
A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter.
A galaxy cluster, or cluster of galaxies, is a structure that consists of anywhere from hundreds to thousands of galaxies that are bound together by gravity with typical masses ranging from 1014–1015 solar masses.
The galaxy color–magnitude diagram shows the relationship between absolute magnitude (a measure of luminosity) and mass of galaxies.
The distribution reveals fine, filamentary structures.
The study of galaxy formation and evolution is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning, the formation of the first galaxies, the way galaxies change over time, and the processes that have generated the variety of structures observed in nearby galaxies.
A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxies larger than groups that are first-order clustering are called galaxy clusters.
Galaxy groups and clusters are the largest known gravitationally bound objects to have arisen thus far in the process of cosmic structure formation.
Galaxy mergers can occur when two (or more) galaxies collide.
Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance.
The rotation curve of a disc galaxy (also called a velocity curve) is a plot of the orbital speeds of visible stars or gas in that galaxy versus their radial distance from that galaxy's centre.
Galileo Galilei (15 February 1564Drake (1978, p. 1). The date of Galileo's birth is given according to the Julian calendar, which was then in force throughout Christendom. In 1582 it was replaced in Italy and several other Catholic countries with the Gregorian calendar. Unless otherwise indicated, dates in this article are given according to the Gregorian calendar. – 8 January 1642) was an Italian polymath.
A grand design spiral galaxy is a type of spiral galaxy with prominent and well-defined spiral arms, as opposed to multi-arm and flocculent spirals which have subtler structural features.
A hot, dust-obscured galaxy, or hot DOG, is a rare type of quasar.
Hubble's law is the name for the observation in physical cosmology that.
The Illustris project is an ongoing series of astrophysical simulations run by an international collaboration of scientists.
Interacting galaxies (colliding galaxies) are galaxies whose gravitational fields result in a disturbance of one another.
Intergalactic dust is cosmic dust in between galaxies in intergalactic space.
An intergalactic star, also known as an intracluster star or a rogue star, is a star not gravitationally bound to any galaxy.
Intergalactic travel is the term used for hypothetical manned or unmanned travel between galaxies.
An intermediate spiral galaxy is a galaxy that is in between the classifications of a barred spiral galaxy and an unbarred spiral galaxy.
In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy.
An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy.
A jellyfish galaxy is a type of galaxy found in galaxy clusters.
A lenticular galaxy (denoted S0) is a type of galaxy intermediate between an elliptical (denoted E) and a spiral galaxy in galaxy morphological classification schemes.
The following is a list of notable galaxies.
A small number of galaxies or galaxy groups have been named after individual people.
This page lists some galaxy groups and galaxy clusters.
This is a list of known galaxies within 3.59 megaparsecs (11.7 million light-years) of the Solar System, in ascending order of distance.
The following table lists polar-ring galaxies.
This is a list of quasars.
This is a list of ring galaxies.
A spiral galaxy is a type of galaxy characterized by a central bulge of old Population II stars surrounded by a rotating disc of younger Population I stars.
This is a list of voids.
This is a list of lists of galaxies.
The Local Group is the galaxy group that includes the Milky Way.
A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission.
A low-surface-brightness galaxy, or LSB galaxy, is a diffuse galaxy with a surface brightness that, when viewed from Earth, is at least one magnitude lower than the ambient night sky.
Luminous infrared galaxies or LIRGs are galaxies with luminosities, the measurement of brightness, above.
A Lyman-alpha emitter (LAE) is a type of distant galaxy that emits Lyman-alpha radiation.
The Lyon-Meudon Extragalactic Database (LEDA) was a database of galaxies, created in 1983 at the Lyon Observatory.
Magellanic spiral galaxies are (usually) dwarf galaxies which are classified as the type Sm (and SAm, SBm, SABm).
The Markarian galaxies are a class of galaxies that have nuclei with excessive amounts of ultraviolet emissions compared with other galaxies.
The Milky Way is the galaxy that contains our Solar System.
The Morphological Catalogue of Galaxies (MCG) or Morfologiceskij Katalog Galaktik, is a Russian catalogue of 30,642 galaxies compiled by Boris Vorontsov-Velyaminov and V. P. Arkhipova.
The Multiwavelength Atlas of Galaxies is a textbook and atlas of 35 well studied galaxies (including our Galaxy) authored by Glen Mackie of the Centre for Astrophysics & Supercomputing, Swinburne University of Technology.
The Norma Arm is a minor spiral arm of the Milky Way extending from and around its central hub region.
The Orion Arm is a minor spiral arm of the Milky Way some across and approximately in length, containing the Solar System, including the Earth.
An outline, also called a hierarchical outline, is a list arranged to show hierarchical relationships and is a type of tree structure.
A Pea galaxy, also referred to as a Pea or Green Pea, might be a type of Luminous Blue Compact Galaxy which is undergoing very high rates of star formation.
A peculiar galaxy is a galaxy of unusual size, shape, or composition.
The Perseus Arm is one of two major spiral arms of the Milky Way galaxy.
Physical cosmology is the study of the largest-scale structures and dynamics of the Universe and is concerned with fundamental questions about its origin, structure, evolution, and ultimate fate.
A polar-ring galaxy is a type of galaxy in which an outer ring of gas and stars rotates over the poles of the galaxy.
The Catalogue of Principal Galaxies (PGC) is an astronomical catalog published in 1989 that lists B1950 and J2000 equatorial coordinates and cross-identifications for 73,197 galaxies.
In physical cosmology, a protogalaxy, which could also be called a "primeval galaxy", is a cloud of gas which is forming into a galaxy.
A quasar (also known as a QSO or quasi-stellar object) is an extremely luminous active galactic nucleus (AGN).
Radio galaxies and their relatives, radio-loud quasars and blazars, are types of active galaxy that are very luminous at radio wavelengths, with luminosities up to 1039 W between 10 MHz and 100 GHz.
A ring galaxy is a galaxy with a circle-like appearance.
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.
A satellite galaxy is a smaller companion galaxy that travels on bound orbits within the gravitational potential of a more massive and luminous host galaxy (also known as the primary galaxy).
The Scutum–Centaurus Arm, also known as Scutum-Crux arm, is a long, diffuse curving streamer of stars, gas and dust that spirals outward from the proximate end of the Milky Way's central bar.
Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars.
The Shapley-Ames Catalog of Bright Galaxies is a catalog of galaxies published in 1932 that includes observations of 1249 objects brighter than 13.2 magnitude.
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.
A starburst galaxy is a galaxy undergoing an exceptionally high rate of star formation, as compared to the long-term average rate of star formation in the galaxy or the star formation rate observed in most other galaxies.
A supercluster is a large group of smaller galaxy clusters or galaxy groups; it is among the largest-known structures of the cosmos.
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.
The type-cD galaxy (also cD-type galaxy, cD galaxy) is a galaxy morphology classification, a subtype of type-D giant elliptical galaxy.
An ultra diffuse galaxy (UDG) is an extremely low luminosity galaxy, the first example of which was discovered in the nearby Virgo Cluster by Allan Sandage and Bruno Binggeli in 1984.
An unbarred lenticular galaxy is a lenticular version of an unbarred spiral galaxy.
An unbarred spiral galaxy is a type of spiral galaxy without a central bar, or one that is not a barred spiral galaxy.
The University of Ottawa (uOttawa or U of O) (Université d'Ottawa) is a bilingual public research university in Ottawa, Ontario, Canada.
The University of St Andrews (informally known as St Andrews University or simply St Andrews; abbreviated as St And, from the Latin Sancti Andreae, in post-nominals) is a British public research university in St Andrews, Fife, Scotland.
The Uppsala General Catalogue of Galaxies (UGC) is a catalogue of 12,921 galaxies visible from the northern hemisphere.
Cosmic voids are vast spaces between filaments (the largest-scale structures in the universe), which contain very few or no galaxies.
Void galaxies are galaxies which exist in cosmological voids.
Vorontsov-Vel'yaminov Interacting Galaxies are those included in the Atlas and Catalogue of Interacting Galaxies, by B.A. Vorontsov-Vel'yaminov, R.I. Noskova and V.P. Arkhipova.
X-shaped (or "winged") radio galaxies are a class of extragalactic radio source that exhibit two, low-surface-brightness radio lobes (the "wings") oriented at an angle to the active, or high-surface-brightness, lobes.