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.
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 ...
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.
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
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 ...
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.
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
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 ...
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