Messier 74 (also known as NGC 628 and Phantom Galaxy) is a large spiral galaxy in the equatorial constellation Pisces.[lower-alpha 1] It is about 32 million light-years away from Earth.[6] The galaxy contains two clearly defined spiral arms and is therefore used as an archetypal example of a grand design spiral galaxy.[7] The galaxy's low surface brightness makes it the most difficult Messier object for amateur astronomers to observe.[8][9] Its relatively large angular (that is, apparent) size and the galaxy's face-on orientation make it an ideal object for professional astronomers who want to study spiral arm structure and spiral density waves. It is estimated that M74 hosts about 100 billion stars.[6]
M74 was discovered by Pierre Méchain in 1780. He then communicated his discovery to Charles Messier, who listed the galaxy in his catalog.[9]
M74 observed by JWST.
In July 2022, it was observed by the James Webb Space Telescope, not long after it began taking its first pictures and observations and soon astronomy image processor Judy Schmidt made images of it available.[10]
Supernovae
Three supernovae are known to have taken place within it:[2]SN 2002ap,[11]SN 2003gd,[12] and SN 2013ej (the numbers denote the year).[13] The latter was bright as 10th magnitude when viewed from the surface of Earth, so visible from almost all modern telescopes in a good night sky.[13]
SN 2002ap was one of few Type Ic supernovae (which denotes hypernovae) recorded within 10 Mpc every century.[14][15][16] This explosion has been used to test theories on the origins of others further away[15] and theories on the emission by supernovae of gamma ray bursts.[16]
SN 2003gd is a Type II-P supernova.[17] Type II supernovae have known luminosities, so they can be used to accurately measure distances. The distance measured to M74 using SN 2003gd is 9.6 ± 2.8Mpc, or 31 ± 9 millionly.[3] For comparison, distances measured using the brightest supergiants are 7.7 ± 1.7Mpc and 9.6 ± 2.2Mpc.[3] Ben Sugerman found a "light echo" – a later reflection of the explosion – associated with SN 2003gd.[18] This is one of the few supernovae in which such a reflection has been found. This reflection appears to be from dust in a sheet-like cloud that lies in front of the supernova, and it can be used to determine the composition of the interstellar dust.[18][19]
Galaxy group
This is the brightest member of the M74 Group, a group of 5 to 7 galaxies that also includes the peculiarspiral galaxyNGC 660 and a few irregular galaxies.[20][21][22] Different group membership identification methods (ranging from a clear, to likely, to perhaps historic gravitational tie) identify several objects of the group in common,[22] and a few galaxies whose exact status within such groupings is currently uncertain.[22]
M74 as observed with the Spitzer Space Telescope as part of the Spitzer Infrared Nearby Galaxy Survey. The blue colors represent the 3.6 micrometre emission from stars. The green and red colors represent the 5.8 and 8.0micrometre emission from polycyclic aromatic hydrocarbons and possibly dust.
Suspected black hole
In 2005[23][lower-alpha 2] the Chandra X-ray Observatory announced its observation of an ultraluminous X-ray source (ULX) in M74, radiating more X-ray power than a neutron star, in periodic intervals of around two hours. It has an estimated mass of 10000M☉. This is an indicator of an intermediate-mass black hole. This would be a rather uncommon class, in between in size of stellar black holes and the massive black holes theorized to be in the center of many galaxies. Such an object is believed to form from lesser ("stellar") black holes within a star cluster. The source has been given identification number CXOU J013651.1+154547.
Amateur astronomy observation
Messier 74 is 1.5° east-northeast of Eta Piscium.[8][9] This galaxy has the second-lowest Earth-surface brightness of any Messier object. (M101 has the lowest.) It requires a good night sky.[9][8] This galaxy may be best viewed under low magnification; when highly magnified, the diffuse emission becomes more extended and appears too faint to be seen by many people.[9] Additionally, M74 may be more easily seen when using averted vision when the eyes are fully dark adapted.[8][9]
See also
List of Messier objects
Wikimedia Commons has media related to Messier 74.
R. W. Sinnott, ed. (1988). The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer. Sky Publishing Corporation / Cambridge University Press. ISBN978-0-933346-51-2.
S. J. Smartt; P. M. Vreeswijk; E. Ramirez-Ruiz; G. F. Gilmore; W. P. S. Meikle; A. M. N. Ferguson; etal. (2002). "On the Progenitor of the Type Ic Supernova 2002ap". Astrophysical Journal. 572 (2): L147–L151. arXiv:astro-ph/0205241. Bibcode:2002ApJ...572L.147S. doi:10.1086/341747. S2CID2130591.
R. B. Tully (1988). Nearby Galaxies Catalog. Cambridge University Press. ISBN978-0-521-35299-4.
A. Garcia (1993). "General study of group membership. II – Determination of nearby groups". Astronomy and Astrophysics Supplement. 100: 47–90. Bibcode:1993A&AS..100...47G.
G. Giuricin; C. Marinoni; L. Ceriani; A. Pisani (2000). "Nearby Optical Galaxies: Selection of the Sample and Identification of Groups". Astrophysical Journal. 543 (1): 178–194. arXiv:astro-ph/0001140. Bibcode:2000ApJ...543..178G. doi:10.1086/317070. S2CID9618325.
Другой контент может иметь иную лицензию. Перед использованием материалов сайта WikiSort.org внимательно изучите правила лицензирования конкретных элементов наполнения сайта.
2019-2025 WikiSort.org - проект по пересортировке и дополнению контента Википедии