M64 (NGC 4826) (The Black-eye Galaxy) (The Evil Eye Galaxy)
Distance: 24.5 Million Light Years

Right Ascension: 12 : 56.7 (hours : minutes)
Declination: +21 : 41 (degrees : minutes)

M64 is a nearby and relatively isolated spiral galaxy located within the outskirts of the loose group CVn 1 which also includes M94 and about 15 other members spread over an area of 18 million square light years. The galaxy is known for its prominent dust lane complex asymmetrically placed across its prominent bulge on its northeastern side which has given rise to its moniker "the black-eye galaxy". Among all its features the most distinguishing is the existence of two distinct counter-rotating disk components. The total gaseous mass of the galaxy is about 400 million solar masses which is split fairly equally between the two disks. Of the total mass 53% lies in the inner disk within a radius of 3500 light years and 47% lies in the vast outer disk within a radius of about 36,000 light years. The gas within the inner disk has an extremely high density which drives a high rate of star formation. Almost all the HII regions are found in the inner disk.

The outer disk is coplanar to the inner and is mostly gaseous in content in contrast to the inner disk which contains both stars and gas. The outer disk is counterrotating in respect to the inner stellar disk but is decelerating and will most likely not survive as a separate disk system for more than another billion years (5 to 10 rotations). The origin of the dual counterrotating disks is almost certainly a merger of two disk galaxies having opposite disk rotations. Simulations suggest this event occurred about one billion years ago when the two progenitor galaxies approached each other at a plane perpendicular to their spin vectors eventually settling into a merged equilibrium state as it exists now.

The postulated merger has had other interesting effects on M64. M64 has a relatively large molecular gas content compared to other galaxies its size. Presumably the extra gas was infused at the time of the merger. In most spirals similar to the Milky Way, molecular gas is predominantly clumped within giant molecular clouds ranging in size from 6 to 300 light years in diamater. It may be that in some galaxies like M64 the molecular clouds blend together in a sea of molecular gas rather than forming giant molecular clouds. Recent studies of the molecular gas composition of M64 were done at radio wavelengths and have concluded that possibly up to 60% of its molecular gas may be in a diffuse state with the remainder in giant molecular clouds.

The dusty environs of the central region of M64 dubbed the "evil eye" have been found to exhibit a phenomenon called ERE or Extended Red Emission. ERE regions emit light through photoluminescence of nanometer sized dust particles. Star forming regions within the central region of M64 produces UV radiation which interacts with the abundant dust in the center of the galaxy. The phenomena may explain the brightness of the conspicuous dust lane complex.