NGC 4151 (Eye Of Sauron),NGC 4156 (Canes Venatici)

NGC 4151 is an intermediate spiral Seyfert galaxy located 43 million light-years from Earth, in the

constellation Canes Venatici. The galaxy was first mentioned by William Herschel on March 17, 1787; it was

one of the two Seyfert galaxies described in the paper which defined the term. It is one of the nearest

galaxies to Earth to contain an actively growing supermassive black hole; it was speculated that the nucleus

may host a binary black hole, with about 40 million and about 10 million solar masses respectively, orbiting

with a 15.8-year period. This is, however, still a matter of active debate.

Some astronomers nickname it the "Eye of Sauron" from its appearance.

X-ray source

Astronomers using data from the European Space Agency’s XMM-Newton satellite have found a long-sought X-ray

signal from NGC 4151. When the black hole’s X-ray source flares, its accretion disk reflects the emission

about half an hour later.

A litte tidal tail can be seen into the bottom of the galaxy...and also in the spiral galaxy NGC 4156..

Credits NASA & Wikipedia