The Hubble sequence is a morphological classification scheme for galaxies published by Edwin Hubble in 1926. It is often colloquially known as the Hubble tuning-fork diagram because the shape in which it is traditionally represented resembles a tuning fork. It was invented by John Henry Reynolds and Sir James Jeans.
Spiral galaxies form a class of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, form part of the Hubble sequence. Most spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as the bulge. These are often surrounded by a much fainter halo of stars, many of which reside in globular clusters.
Sohail Khan created this galaxy because he is stupid An irregular galaxy is a galaxy that does not have a distinct regular shape, unlike a spiral or an elliptical galaxy. Irregular galaxies do not fall into any of the regular classes of the Hubble sequence, and they are often chaotic in appearance, with neither a nuclear bulge nor any trace of spiral arm structure.
A lenticular galaxy is a type of galaxy intermediate between an elliptical and a spiral galaxy in galaxy morphological classification schemes. It contains a large-scale disc but does not have large-scale spiral arms. Lenticular galaxies are disc galaxies that have used up or lost most of their interstellar matter and therefore have very little ongoing star formation. They may, however, retain significant dust in their disks. As a result, they consist mainly of aging stars. Despite the morphological differences, lenticular and elliptical galaxies share common properties like spectral features and scaling relations. Both can be considered early-type galaxies that are passively evolving, at least in the local part of the Universe. Connecting the E galaxies with the S0 galaxies are the ES galaxies with intermediate-scale discs.
Messier 83 or M83, also known as the Southern Pinwheel Galaxy and NGC 5236, is a barred spiral galaxy approximately 15 million light-years away in the constellation borders of Hydra and Centaurus. Nicolas-Louis de Lacaille discovered M83 on 23 February 1752 at the Cape of Good Hope. Charles Messier added it to his catalogue of nebulous objects in March 1781.
Messier 61 is an intermediate barred spiral galaxy in the Virgo Cluster of galaxies. It was first discovered by Barnaba Oriani on May 5, 1779, six days before Charles Messier discovered the same galaxy. Messier had observed it on the same night as Oriani but had mistaken it for a comet. Its distance has been estimated to be 45.61 million light years from the Milky Way Galaxy. It is a member of the M61 Group of galaxies, which is a member of the Virgo II Groups, a series of galaxies and galaxy clusters strung out from the southern edge of the Virgo Supercluster.
The Black Eye Galaxy is a relatively isolated spiral galaxy 17 million light-years away in the mildly northern constellation of Coma Berenices. It was discovered by Edward Pigott in March 1779, and independently by Johann Elert Bode in April of the same year, as well as by Charles Messier 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 astronomers due to its form in small telescopes and visibility across inhabited latitudes.
Galaxy morphological classification is a system used by astronomers to divide galaxies into groups based on their visual appearance. There are several schemes in use by which galaxies can be classified according to their morphologies, the most famous being the Hubble sequence, devised by Edwin Hubble and later expanded by Gérard de Vaucouleurs and Allan Sandage. However, galaxy classification and morphology are now largely done using computational methods and physical morphology.
Messier 77 (M77), also known as NGC 1068 or the Squid Galaxy, is a barred spiral galaxy in the constellation Cetus. It is about 47 million light-years (14 Mpc) away from Earth. Messier 77 was discovered by Pierre Méchain in 1780, who originally described it as a nebula. Méchain then communicated his discovery to Charles Messier, who subsequently listed the object in his catalog. Both Messier and William Herschel described this galaxy as a star cluster. Today, however, the object is known to be a galaxy.
NGC 1, also occasionally referred to as GC 1, UGC 57, PGC 564 or Holm 2a is an intermediate spiral galaxy of the morphological type Sbc, located approximately 210 to 215 million light-years from the Solar System in the constellation Pegasus. It was discovered on 30 September 1861 by Heinrich d'Arrest.
An unbarred spiral galaxy is a type of spiral galaxy without a central bar, or one that is not a barred spiral galaxy. It is designated with an SA in the galaxy morphological classification scheme.
NGC 5364 is a grand design spiral galaxy located 54.5 million light years away in the constellation Virgo. It is inclined to the line of sight from the Earth at an angle of 47° along a position angle of 25°. It is a member of the NGC 5364 Group of galaxies, itself one of the Virgo III Groups strung out to the east of the Virgo Supercluster of galaxies.
The galaxy color–magnitude diagram shows the relationship between absolute magnitude and mass of galaxies. A preliminary description of the three areas of this diagram was made in 2003 by Eric F. Bell et al. from the COMBO-17 survey that clarified the bimodal distribution of red and blue galaxies as seen in the analysis of Sloan Digital Sky Survey data and even in de Vaucouleurs's 1961 analyses of galaxy morphology.
NGC 5755 is a barred spiral galaxy in the constellation Boötes, member of Arp 297 interacting galaxies group of four: NGC 5752, NGC 5753, NGC 5754, and NGC 5755.
NGC 10 is a spiral galaxy located in the southern constellation of Sculptor. It was discovered by John Herschel on 25 September 1834. The galaxy is located at a distance of 346 Mly from the Sun. Its morphological classification in the De Vaucouleurs system is SAB(rs)bc, where the 'SAB' denotes a weak-barred spiral, '(rs)' indicates a slight ring-like structure, and 'bc' means the spiral arms are moderately to loosely wound. Paturel et al. (2003) assigned this galaxy a classification of SBbc, indicating a barred spiral galaxy.
NGC 24 is a spiral galaxy in the southern constellation of Sculptor, about 23.8 megalight-years distant from the Milky Way. It was discovered by British astronomer William Herschel in 1785, and measures some 40,000 light-years across. The general shape of this galaxy is specified by its morphological classification of SA(s)c, which indicates it is an unbarred spiral with no ring-like structure and moderate to loosely-wound spiral arms. This galaxy is positioned in the vicinity of the Sculptor Group, but is actually a background object that is more than three times as distant. It may form a pair with another background galaxy, NGC 45.
Magellanic spiral galaxies are (usually) dwarf galaxies which are classified as the type Sm. They are galaxies with one single spiral arm, and are named after their prototype, the Large Magellanic Cloud, an SBm galaxy. They can be considered to be intermediate between dwarf spiral galaxies and irregular galaxies.
NGC 4444 is an intermediate spiral galaxy in the constellation Centaurus. The morphological classification places it midway on the continuum between a barred spiral (SB) and an unbarred spiral (SA), with an inner region that lies between a ring-like (r) and a purely spiral form (s), and medium- (b) to loosely wound (c) outer spiral arms. This makes it a hybrid ringed, barred spiral galaxy. It has an angular size of 2.4 × 1.6 arcminutes and the estimated mass M is given log M = 9.76, yielding 5.8 billion solar masses.
NGC 4440 is a barred spiral galaxy located about 55 million light-years away in the constellation of Virgo. NGC 4440 was discovered by astronomer William Herschel on April 17, 1784. It is a member of the Virgo Cluster.
NGC 765 is an intermediate spiral galaxy located in the constellation Aries. It is located at a distance of circa 220 million light years from Earth, which, given its apparent dimensions, means that NGC 765 is about 195,000 light years across. It was discovered by Albert Marth on October 8, 1864. The galaxy has an extensive hydrogen (HI) disk with low surface brightness, whose diameter is estimated to be 240 kpc.
