Messier 65 (also known as NGC 3623) is an

intermediate spiral galaxy An intermediate spiral galaxy is a galaxy that is in between the classifications of a barred spiral galaxy and an unbarred spiral galaxy. It is designated as SAB in the galaxy morphological classification system devised by Gerard de Vaucouleur ...

about 35 million

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

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 ...

Leo, within its highly

equatorial Equatorial may refer to something related to: *Earth's equator **the tropics, the Earth's equatorial region **tropical climate *the Celestial equator ** equatorial orbit **equatorial coordinate system ** equatorial mount, of telescopes * equatorial ...

southern half. It was discovered 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 ...

in 1780. With M66 and NGC 3628, it forms the

Leo Triplet The Leo Triplet (also known as the M66 Group) is a small group of galaxies about 35 million light-years away in the constellation Leo. This galaxy group consists of the spiral galaxies M65, M66, and NGC 3628. Members The table below lists ...

, a small close

group of galaxies A galaxy group or group of galaxies (GrG) is an aggregation of galaxies comprising about 50 or fewer gravitationally bound members, each at least as luminous as the Milky Way (about 1010 times the luminosity of the Sun); collections of galaxies ...

Discovery

M65 was discovered by Charles Messier and included in his

Messier Objects The Messier objects are a set of 110 astronomical objects catalogued by the French astronomer Charles Messier in his ''Catalogue des Nébuleuses et des Amas d'Étoiles'' (''Catalogue of Nebulae and Star Clusters''). Because Messier was only int ...

list. However,

William Henry Smyth Admiral William Henry Smyth (21 January 1788 – 8 September 1865) was a Royal Navy officer, hydrographer, astronomer and numismatist. He is noted for his involvement in the early history of a number of learned societies, for his hydrographic ...

accidentally attributed the discovery to

Pierre Méchain Pierre François André Méchain (; 16 August 1744 – 20 September 1804) was a French astronomer and surveyor who, with Charles Messier, was a major contributor to the early study of deep-sky objects and comets. Life Pierre Méchain was born i ...

in his popular 19th-century astronomical work ''A Cycle of Celestial Objects'' (stating "They 65 and M66were pointed out by Méchain to Messier in 1780"). This error was in turn picked up by Kenneth Glyn Jones in ''Messier's Nebulae and Star Clusters''. This has since ramified into a number of other books by a variety of authors.

Star formation

The galaxy is low in dust and gas, and there is little

star formation Star formation is the process by which dense regions within molecular clouds in The "medium" is present further soon.-->interstellar space

in it, although there has been some relatively recently in the arms. The ratio of old stars to new stars is correspondingly quite high. In most wavelengths it is quite uninteresting, though there is a radio source visible in the NVSS, offset from the core by about two arc-minutes. The identity of the source is uncertain, as it has not been identified visually, or formally studied in any published papers.

Interaction with other galaxies

To the eye, M65's disk appears slightly warped, and its relatively recent burst of star formation is also suggestive of some external disturbance. Rots (1978) suggests that the two other galaxies in the Leo Triplet interacted with each other about 800 million years ago. Recent research by Zhiyu Duan suggests that M65 may also have interacted, though much less strongly. He also notes that M65 may have a central bar—it is difficult to tell because the galaxy is seen from an oblique angle—a feature which is suggestive of tidal disruption.

Gallery

Messier65 - SDSS DR14.jpg, Messier 65 by the

Sloan Digital Sky Survey The Sloan Digital Sky Survey or SDSS is a major multi-spectral imaging and spectroscopic redshift survey using a dedicated 2.5-m wide-angle optical telescope at Apache Point Observatory in New Mexico, United States. The project began in 2000 a ...

Messier 65 Hubble WikiSky.jpg, HST image of M65 NGC3623-hst-R814GB450.jpg, M65 by

Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versa ...

M65 Galaxy from the Mount Lemmon SkyCenter Schulman Telescope courtesy Adam Block.jpg, M65 as imaged from the

Mount Lemmon Observatory Mount Lemmon Observatory (MLO), also known as the Mount Lemmon Infrared Observatory, is an astronomical observatory located on Mount Lemmon in the Santa Catalina Mountains approximately northeast of Tucson, Arizona (US). The site in the Coronad ...

Messier 065 2MASS.jpg, Messier 65 by

2MASS The Two Micron All-Sky Survey, or 2MASS, was an astronomical survey of the whole sky in infrared light. It took place between 1997 and 2001, in two different locations: at the U.S. Fred Lawrence Whipple Observatory on Mount Hopkins, Arizona, and ...

References

External links