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.
More recently, astronomers have discovered objects that fit none of Hubble's ...
spiral arms come from the ends of a bar through the nucleus rather than from the
nucleus itself. 4. ... Collisions between galaxies are not unusual because on
average galaxies ..... An active galaxy is a galaxy with an unusually luminous
Apr 6, 2016 ... Astronomers have uncovered a near-record breaking supermassive black hole,
... “The newly discovered supersized black hole resides in the center of a .....
Occasionally, some primordial black holes will pass close enough to be ... face-
on spiral galaxy NGC 6814, whose luminous nucleus and spectacular ...
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
Jan 29, 2016 ... However, in an unexpected discovery, astronomers found LO95 ... This growing
class of unusual spirals continues to raise significant ... This is demonstrated by
the striking face-on spiral galaxy NGC 6814, whose luminous nucleus and ...
NGC 6814 has an extremely bright nucleus, a telltale sign that the ...
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
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 ...
I. INTRODUCTION Since the discovery ofactive galactic nuclei, observational ...
The synthesis of earlier work plus some unpublished emission-line images ... 1
kpc*) ofthe nucleus of NGC 1068 that are unusual for a galaxy of the same (Sb)
Hubble type. ... (1983), among others, have mapped the radio continuum at a
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 ...