It's a striking example of a "grand design spiral galaxy," one with well-defined arms, viewed straight on.
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Not only was BX442 revealed to be a genuine spiral galaxy, but part of a sub-class known as 'grand-design' spirals. Most spiral galaxies have subtler features and the arms of the spiral are not necessarily well-defined. A grand design spiral galaxy has very clearly well-formed and distinct arms that significantly stretch out around the galaxy center. Of all spiral galaxies, only about 10% of them are classified as a grand design spiral galaxy.
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BX442 (Q2343-BX442) is a grand design spiral galaxy of type Sc. It has a companion dwarf galaxy. It is the most distant known grand design spiral galaxy in the universe, with a redshift of z=2.1765 ± 0.0001. Although commonly referred to as the oldest known grand design spiral galaxy in the universe, it is more accurately the earliest such galaxy known to exist in the universe, with a lookback time (the difference between the age of the universe now and the age of the universe at the time light left the galaxy ) of 10.7 billion years in the concordance cosmology. This time estimate means that structure seen in BX442 developed roughly 3 billion years after the Big Bang, 10 kiloparsecs (30,000 ly) in diameter, and has a mass of .
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NGC 6907 by 2MASS. NGC 6908 can be seen at the eastern arm. NGC 6907 is a grand design spiral galaxy with two spiral arms. It has an elliptical bulge that is skewed towards the base of the arms.
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NGC 5643 is a grand design spiral galaxy, with two well-defined, symmetric arms. In the circumnuclear region are present and other dust spirals, but the two main dust arms are wider. The galaxy is seen nearly face on, at an inclination of ∼ 27°.
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NGC 4088 is an intermediate spiral galaxy in the constellation Ursa Major. The galaxy forms a physical pair with NGC 4085, which is located 11′ away. NGC 4088 is a grand design spiral galaxy. This means that the spiral arms in the galaxy's disk are sharply defined.
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NGC 7096 is a grand-design spiral galaxy located about 130 million light-years away in the constellation of Indus. NGC 7096 is also part of a group of galaxies that contains the galaxy NGC 7083. NGC 7096 was discovered by astronomer John Herschel on August 31, 1836.
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NGC 3631 is a grand design spiral galaxy and features two principal spiral arms, which begin near the center. The two main arms branch into secondary arms with lower surface brightness. The galaxy shows moderate- to-high star formation rate and bright HII regions are present in all the arms.Sandage, A., Bedke, J. (1994) The Carnegie Atlas of Galaxies.
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NGC 5474 is a peculiar dwarf galaxy in the constellation Ursa Major. It is one of several companion galaxies of the Pinwheel Galaxy (M101), a grand-design spiral galaxy. Among the Pinwheel Galaxy's companions, this galaxy is the closest to the Pinwheel Galaxy itself. The gravitational interaction between NGC 5474 and the Pinwheel Galaxy has strongly distorted the former.
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It is not perfectly symmetrical in the eyepiece, rather, the northwest side is flattened and the nucleus has a southwest-to-northeast bar. A smaller sister to the Milky Way, it is a grand design spiral galaxy 40,000 light-years across. NGC 2865 is relatively youthful and dynamic, with a rapidly rotating disc full of young stars and metal-rich gas.
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NGC 1241 is a barred spiral galaxy seen at an inclination. It has two well defined dusty spiral arms, and thus is characterised as a grand design spiral galaxy. The bulge is boxy, characteristic of a barred galaxy, with the arms emerging from each end of the bar, with the north one appearing more tightly wound than the southern. The main arms branch into smaller ones.
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The galaxy has a large elliptical bulge and maybe a weak bar. It is a grand design spiral galaxy, with two tightly wrapped arms emanating from the bulge. The arms are thin, smooth and well defined and can be traced for nearly one and a half revolutions before fading. Two symmetric arm sections or arcs are observed in the central part of the galaxy.
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Messier 74 (also known as NGC 628 and Phantom Galaxy) is a spiral galaxy in the constellation Pisces. It is at a distance of about 32 million light-years away from Earth. The galaxy contains two clearly defined spiral arms and is therefore used as an archetypal example of a grand design spiral galaxy. The galaxy's low surface brightness makes it the most difficult Messier object for amateur astronomers to observe.
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NGC 5247 is a face-on unbarred spiral galaxy located some 60 million light years away in the constellation Virgo. It most likely belongs to the Virgo Supercluster of galaxies; the same supercluster that hosts the Milky Way galaxy. This is a grand design spiral galaxy that displays no indications of distortion caused by interaction with other galaxies. It has two spiral arms that bifurcate after wrapping halfway around the nucleus.
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Messier 99 or M99, also known as NGC 4254, is a grand design spiral galaxy in the northern constellation Coma Berenices approximately in distance from the Milky Way. It was discovered by Pierre Méchain on March 17, 1781. The discovery was then reported to Charles Messier, who included the object in the Messier Catalogue of comet-like objects. Messier 99 was one of the first galaxies in which a spiral pattern was seen.
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The Whirlpool Galaxy, also known as Messier 51a, M51a, and NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus. It lies in the constellation Canes Venatici, and was the first galaxy to be classified as a spiral galaxy. Its distance is estimated to be 23 million light-years away from Earth. The galaxy and its companion, NGC 5195, are easily observed by amateur astronomers, and the two galaxies may be seen with binoculars.
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NGC 6118 is a grand design spiral galaxy located 83 million light-years away in the constellation Serpens (the Snake). It measures roughly 110,000 light- years across; about the same as our own galaxy, the Milky Way. Its shape is classified as "SA(s)cd," meaning that it is unbarred and has several rather loosely wound spiral arms. The large numbers of bright bluish knots are active star-forming regions where some very luminous and young stars can be perceived.
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NGC 3310 is a grand design spiral galaxy in the constellation Ursa Major. It is a starburst galaxy and it is likely that NGC 3310 collided with one of its satellite galaxies about 100 million years ago, triggering widespread star formation. It is thought to be located approximately 46 million light-years away from the Earth, and is thought to be about 22,000 light-years wide. The ring clusters of NGC 3310 have been undergoing starburst activity for at least the last 40 million years.
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Messier 81 (also known as NGC 3031 or Bode's Galaxy) is a grand design spiral galaxy about 12 million light-years away, with a diameter of 90,000 light years, about half the size of the Milky Way, in the constellation Ursa Major. Due to its proximity to Earth, large size, and active galactic nucleus (which harbors a 70 million supermassive black hole), Messier 81 has been studied extensively by professional astronomers. The galaxy's large size and relatively high brightness also makes it a popular target for amateur astronomers.
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In the Hubble classification scheme, spiral galaxies are listed as type S, followed by a letter (a, b, or c) which indicates the degree of tightness of the spiral arms and the size of the central bulge. An Sa galaxy has tightly wound, poorly defined arms and possesses a relatively large core region. At the other extreme, an Sc galaxy has open, well-defined arms and a small core region. A galaxy with poorly defined arms is sometimes referred to as a flocculent spiral galaxy; in contrast to the grand design spiral galaxy that has prominent and well-defined spiral arms.
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A Spitzer Space Telescope image of Messier 81, a grand design spiral. A grand design spiral galaxy is a type of spiral galaxy with prominent and well- defined spiral arms, as opposed to multi-arm and flocculent spirals which have subtler structural features. The spiral arms of a grand design galaxy extend clearly around the galaxy through many radians and can be observed over a large fraction of the galaxy's radius. As of 2002, approximately 10 percent of all currently known spiral galaxies are classified as grand design type spirals, including M51, M74, M81, M83, and M101.
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NGC 2775, a prominent flocculent spiral galaxy A flocculent spiral galaxy is a type of spiral galaxy. Unlike the well-defined spiral architecture of a grand design spiral galaxy, flocculent (meaning "fluffy") galaxies are patchy, with discontinuous spiral arms.COSMOS - SAO Encyclopedia of Astronomy, "Grand Design Spiral" (accessed 23 April 2010)COSMOS - SAO Encyclopedia of Astronomy, "Flocculent Spiral" (accessed 23 April 2010) Self-propagating star formation is the apparent explanation for the structure of flocculent spirals. Approximately 30% of spirals are flocculent, 10% are grand design, and the rest are referred to as "multi-armed".Case Western Reserve University, Chris Mihos, ASTR222 - Spring 2008, "Spiral Structure" (accessed 23 April 2010) The multiple-arm type is sometimes grouped into the flocculent category.
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