Seyfert galaxies are one of the two largest groups of active galaxies, along with
quasars. ... In 1943, Carl Keenan Seyfert discovered more galaxies similar to
NGC 1068 and reported that ... At 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.
Most large galaxies have ~10<sup>11</sup> Mo of stars, ~10<sup>9-10</sup> Mo of interstellar gas, and
... while the more luminous quasi-stellar objects, like quasars, exhibit accretion
onto a ... lines from normal stars, Seyfert galaxy nuclei have strong emission lines
. ... the jets of some blazars: Stronger than X-ray, optical, radio emission
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 ...
Jan 9, 2014 ... This new Hubble image shows the spiral galaxy Messier 83, otherwise ... number
of supernova explosions, and is thought to have a double nucleus lurking at its
core. ... Located some 15 million light-years away in the constellation of Hydra ...
However, Messier 83's centre is mysterious and unusual; the ...
Some galaxies have spiral or pinwheel arms. .... It has a bright nucleus, an
unusually large central bulge, and a prominent dust lane in its ... Most
representatives of this class consist of grainy, highly irregular assemblages of
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
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.
Interest in the M33 nucleus recently has been stimulated by the discovery that it
.... scaled-down versions of M3 l's nucleus, a luminous globular cluster, or some
.... have seen that globular clusters and some Local Group spiral-galaxy nuclei
are similar. ... The M31 nucleus, with a 190 km s~1, is clearly a dynamically
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.