The Black Eye Galaxy (also called Sleeping Beauty Galaxy or Evil Eye Galaxy and designated Messier 64, M64, or NGC 4826) is a relatively isolated

spiral galaxy Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work ''The Realm of the Nebulae''light-year A light-year, alternatively spelled light year, is a large unit of length used to express astronomical distances and is equivalent to about 9.46 trillion kilometers (), or 5.88 trillion miles ().One trillion here is taken to be 1012 ...

s away in the mildly northern

constellation A constellation is an area on the celestial sphere in which a group of visible stars forms Asterism (astronomy), a perceived pattern or outline, typically representing an animal, mythological subject, or inanimate object. The origins of the e ...

Coma Berenices Coma Berenices is an ancient asterism in the northern sky, which has been defined as one of the 88 modern constellations. It is in the direction of the fourth galactic quadrant, between Leo and Boötes, and it is visible in both hemisphere ...

. It was discovered by

Edward Pigott Edward Pigott (1753–1825) was an English astronomer notable for being one of the founders of the study of variable stars. Biography Son of the astronomer Nathaniel Pigott, Pigott's work focused on variable stars. Educated in France with ...

in March 1779, and independently by

Johann Elert Bode Johann Elert Bode (; 19 January 1747 – 23 November 1826) was a German astronomer known for his reformulation and popularisation of the Titius–Bode law. Bode determined the orbit of Uranus and suggested the planet's name. Life and career Bo ...

in April of the same year, as well as by

Charles Messier Charles Messier (; 26 June 1730 – 12 April 1817) was a French astronomer. He published an astronomical catalogue consisting of 110 nebulae and star clusters, which came to be known as the ''Messier objects''. Messier's purpose f ...

the next year. A dark band of absorbing dust partially in front of its bright nucleus gave rise to its nicknames of the "Black Eye", "Evil Eye", or "Sleeping Beauty" galaxy. M64 is well known among

amateur astronomer Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers m ...

s due to its form in small

telescope A telescope is a device used to observe distant objects by their emission, absorption, or reflection of electromagnetic radiation. Originally meaning only an optical instrument using lenses, curved mirrors, or a combination of both to observe ...

s and visibility across inhabited latitudes. This galaxy is inclined 60° to the line-of-sight and has a

position angle In astronomy, position angle (usually abbreviated PA) is the convention for measuring angles on the sky. The International Astronomical Union defines it as the angle measured relative to the north celestial pole (NCP), turning positive into the d ...

of 112°. At the distance of this galaxy, it has a linear scale of per arcsecond. The morphological classification in the De Vaucouleurs system is (R)SA(rs)ab, where the '(R)' indicates an outer ring-like structure, 'SA' denotes a non-barred spiral, '(rs)' means a transitional inner ring/spiral structure, and 'ab' says the spiral arms are fairly tightly wound. Ann et al. (2015) gave it a class of SABa, suggesting a weakly

barred spiral galaxy A barred spiral galaxy is a spiral galaxy with a central bar-shaped structure composed of stars. Bars are found in about two thirds of all spiral galaxies, and generally affect both the motions of stars and interstellar gas within spiral galaxi ...

with tightly wound arms. M64 is a type 2

Seyfert galaxy Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei (very luminous, distant and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra ...

with an HII/

LINER A low-ionization nuclear emission-line region (LINER) is a type of galactic nucleus that is defined by its spectral line emission. The spectra typically include line emission from weakly ionized or neutral atoms, such as O, O+, N+, and S+. ...

nucleus. The central region is a weak source of radio emission. A soft

X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...

source has been detected at the nucleus, which is most likely coming from the circumnuclear region rather than directly from an

active galactic nucleus An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not pr ...

. There is an inner disk of molecular gas that is truncated at a radius of . At present, the non-rotational motions of this disk do not significantly feed the core, but the disk does produce a vigorous rate of

star A star is an astronomical object comprising a luminous spheroid of plasma (physics), plasma held together by its gravity. The List of nearest stars and brown dwarfs, nearest star to Earth is the Sun. Many other stars are visible to the naked ...

formation, with also approximately 100 billion stars inside the galaxy. There is also evidence of a recent large inflow of mass. The

interstellar medium In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstella ...

of Messier 64 consists of two counter-rotating disks that are approximately equal in mass. The inner disk contains the prominent

dust lane A dust lane consists of a relatively dense, obscuring clouds of interstellar dust, observed as a dark swath against the background of a brighter object(s), especially a galaxy. These dust lanes can usually be seen in spiral galaxies, such as th ...

s of the galaxy. The stellar population of the galaxy exhibits no measurable counter-rotation. Possible formation scenarios include a merger with a gas-rich satellite galaxy in a retrograde orbit, or the continued accretion of gas clouds from the

intergalactic medium Intergalactic may refer to: * "Intergalactic" (song), a song by the Beastie Boys * ''Intergalactic'' (TV series), a 2021 UK science fiction TV series * Intergalactic space * Intergalactic travel, travel between galaxies in science fiction and sp ...

. It has a diameter of . M64 Blackeye Galaxy from the Mount Lemmon SkyCenter Schulman Telescope courtesy Adam Block

References

External links

Messier 64, SEDS Messier pages

ESA/Hubble images of M64
* *
a real photo by Pete Albrecht

Black Eye Galaxy (M64) at Constellation Guide
{{DEFAULTSORT:Black Eye Galaxy Unbarred spiral galaxies Coma Berenices Messier objects NGC objects Virgo Supercluster Astronomical objects discovered in 1779 Discoveries by Edward Pigott

See also

References

External links