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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 and, as such, forms part of the ...



The universe started expanding at some time in the past; the universe has an age . b. ..... That some spirals have unusually luminous nuclei was discovered by: a.

galaxy - Types of galaxies | astronomy | Britannica.com


Apr 13, 2016 ... The normal spirals have arms that emanate from the nucleus, while ... Some S0 systems have a hint of structure in the envelope, either .... Q: Quasars, or QSOs, small, extremely luminous objects, many of which are strong radio sources. ..... It was discovered that galaxies and galaxy clusters tend to fall in ...

John Kormendy: Monsters in Galactic Nuclei


Jul 15, 2000 ... Soon after quasars were discovered in 1963, astronomers proposed .... but it does not rule out some other concentration of underluminous matter. ... An unusual aspect of this image is that foreground stars have been removed. .... type between spirals and ellipticals in Edwin Hubble's classification scheme.

Active galactic nuclei - D.E. Osterbrock - NED


Many of the most luminous radio galaxies are morphologically classified as ... In many cases these spectra are earlier in spectral type than normal spirals, ... Only one `Seyfert 2 QSO' has been reported, E 0449-184, originally discovered as .... definition of a very low-luminosity Seyfert 1.8 nucleus with unusually narrow lines .

Galaxies - Astronomy Notes


Jun 2, 2007 ... When the universe was younger, some galaxies produced a lot ... A peculiar group of galaxies are extremely luminous but very compact. ... an ``active galaxy'' to be a galaxy with a very luminous nucleus. ... Later, some other blue star-like objects at large redshifts were discovered to have no radio emission ...

Lecture 24: Nuclear Activity in Galaxies, QSOs - University of Arizona


Some galaxies have been observed to have very unusual activiy in the their ... we discovered that some ordinary looking galaxies has infrared outputs 10 to 100 ... These galaxies were dubbed "Ultra-luminous Infrared Galaxies" or ULIRGS for short. .... and infrared) nuclei which look like stars superposed on spiral galaxies.

Active Galactic Nuclei - University of Arizona


Some of these active galactic nuclei (AGN) make more energy than the entire ... Every galaxy with a large bulge of old stars seems to have a central black ... Carl Seyfert first discovered a type of AGN. ... They are unusually bright in x-rays and infrared. ... Both ellipticals and spirals can emit at radio wavelengths but the most  ...

Active Galaxies - Teach Astronomy


The placid exteriors of some galaxies conceal events of great violence. ... The most luminous of these objects give off the same amount of energy as 1 trillion suns. ... can get pulled in (just like a comet getting pulled into the sun), but as it spirals to ... discovered in 1908 by Edward Fath, who discovered intense emission lines ...

Introduction - Discovery of Active Galactic Nuclei - Department of ...


In the type 1 nuclei, certain emission lines were much broader - the ones that could originate ... The discovery of quasars has been recounted often. ... had to be much more luminous than any ordinary galaxies - hundreds of times brighter. ... Some quasars with unusually weak emission lines share some of these variability ...

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Chapter 17 - Astronomy


More recently, astronomers have discovered objects that fit none of Hubble's categories, ... the spiral arms come from the ends of a bar through the nucleus rather than from the nucleus itself. 4. ..... Some irregulars are seen to be pairs of galaxies in collision. ... An active galaxy is a galaxy with an unusually luminous nucleus...

Hubble View of Galaxy Resembling Atomic Nucleus | NASA


The spiral galaxy NGC 7252 has a superficial resemblance to an atomic nucleus ... Hubble View of a Galaxy Resembling an Atomic Nucleus ... The discovery of this galaxy did not require gravitational lenses because it is an outlying, .... Some irregular galaxies may have once fallen into one of the regular classes of the ...

Astronomers discover colossal 'super spiral' galaxies - Phys.org


Mar 18, 2016 ... In archived NASA data, researchers have discovered "super spiral" ... of spiral galaxies that are as luminous and massive as the biggest, ... were nearby—even the closest lay some 1.2 billion light-years away. ... 53 seen by Ogle and colleagues clearly contain two galactic nuclei, instead of just one as usual.