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Magellanic Stream

January 01, 1970

Not to be confused with Magellanic Bridge.

The Magellanic Stream is a stream of high-velocity clouds of gas extending from the Large and Small Magellanic Clouds over 100° through the Galactic south pole of the Milky Way. The stream contains a gaseous feature dubbed the leading arm.[1] The stream was sighted in 1965 and its relation to the Magellanic Clouds was established in 1974.

Magellanic Stream
Object typeIntergalactic high-velocity cloud
Observation data
(Epoch J2000.0)
ConstellationDorado, Mensa, Sculptor 
00h 32m
Declination−30.0°
[edit on Wikidata]

Discovery and early observations edit

 
Map of Hubble observations overlaid on LAB survey, tracing the origin of the Magellanic Stream.[2]

In 1965, anomalous velocity gas clouds were found in the region of the Magellanic Clouds. The gas stretches for at least 180 degrees across the sky. This corresponds to 180 kpc (600,000 ly) at an approximate distance of 55 kpc (180,000 ly). The gas is very collimated and polar with respect to the Milky Way. The velocity range is huge (from −400 to 400 km s−1 in reference to Local Standard of Rest) and velocity patterns do not follow the rest of the Milky Way. Hence, it was determined to be a classic high-velocity cloud.

However, the gas was not mapped, and the connection to the two Magellanic Clouds was not made. The Magellanic Stream as such was discovered as a Neutral Hydrogen (HI) gas feature near the Magellanic Clouds by Wannier & Wrixon in 1972.[3] Its connection to the Magellanic Clouds was made by Mathewson et al. in 1974.[4]

Owing to the closeness of the Magellanic Clouds and the ability to resolve individual stars and their parallaxes, and proper motion, subsequent observations gave the full 6-dimensional phase space information of both clouds (with very large relative errors for the transverse velocities). This enabled the calculation of the likely past orbit of the Large and the Small Magellanic Cloud in relation to the Milky Way. The calculation necessitated large assumptions, for example, on the shapes and masses of the 3 galaxies, and the nature of dynamical friction between the moving objects. Observations of individual stars revealed details of star formation history.

Models edit

Models describing the formation of the Magellanic Stream had been produced since 1980. Following computing power, the initial models were very simple, non-self-gravitating, and with few particles. Most models predicted a feature leading the Magellanic Clouds. These early models were 'tidal' models. Just like tides on Earth are induced by the gravity of the 'leading' Moon, the models predicted two directions opposite each other, in which particles are preferentially pulled. However, the predicted features were not observed. This led to a few models that did not require a leading element but which had problems of their own. In 1998 a study analysing the full sky survey made by the HIPASS team at Parkes Observatory generated important new observational data. Putman et al. discovered that a mass of high-velocity clouds leading the Magellanic Clouds was actually fully connected to the Magellanic Clouds. So, the leading arm feature had its existence finally established. Furthermore, Lu et al. (1998) and Gibson et al. (2000) established the chemical similarity between the streams and Magellanic Clouds.

Newer, increasingly sophisticated models all tested the Leading Arm Feature hypothesis. These models make heavy use of gravity effects through tidal fields. Some models also rely on ram pressure stripping as a shaping mechanism. Most recent models increasingly include drag from the halo of the Milky Way as well as gas dynamics, star formation and chemical evolution. It is thought that the tidal forces mostly affect the Small Magellanic Cloud, since it has lower mass, and is less gravitationally bound. In contrast, ram pressure stripping mostly affects the Large Magellanic Cloud, because it has a larger reservoir of gas.

Recent observations edit

 
Leading arm of the Magellanic Stream measured by Hubble.[5]

In 2018, research confirmed that the chemical composition of the gas in the Magellanic Stream Leading Arm more closely resembles the composition of the Small Magellanic Cloud, rather than the Large Magellanic Cloud, by looking at light from background quasars shining through the Stream and analysing the spectrum of light that is either absorbed by, or let through it.[6] This analysis confirmed that the gas most likely originated from the Small Magellanic Cloud, thereby indicating that the Large Magellanic Cloud is 'winning' in the gravity tug of both Clouds working on the Magellanic Stream.

In 2019 astronomers discovered the young star cluster Price-Whelan 1 using Gaia data. The star cluster has a low metallicity and belongs to the leading arm of the Magellanic Clouds. The discovery of this star cluster suggests that the leading arm of the Magellanic Clouds is 90,000 light-years away from the Milky Way, only half as far from the Milky Way as previously thought. The star cluster is relatively young, which is a sign of recent star formation in the leading arm.[7]

See also edit

References edit

  1. ^ Nidever, David L.; Majewski, Steven R.; Burton, W. Butler (20 May 2008). "The Origin of the Magellanic Stream and Its Leading Arm". The Astrophysical Journal. 679 (1): 432–459. arXiv:0706.1578. Bibcode:2008ApJ...679..432N. doi:10.1086/587042. S2CID 13399751.
  2. ^ "Hubble finds source of Magellanic Stream". ESA/Hubble Press Release. Retrieved 14 August 2013.
  3. ^ Wannier, P; Wrixon, G.T. (May 1972). "An Unusual High-Velocity Hydrogen Feature". The Astrophysical Journal. 173: L119–L123. Bibcode:1972ApJ...173L.119W. doi:10.1086/180930.
  4. ^ Mathewson, D.S.; Cleary, M.N.; Murray, J.D. (June 1974). "The Magellanic Stream". The Astrophysical Journal. 190: 291–296. Bibcode:1974ApJ...190..291M. doi:10.1086/152875.
  5. ^ "Hubble measures content of the leading arm of the Magellanic Stream". www.spacetelescope.org. Retrieved 4 April 2018.
  6. ^ "Hubble Solves Cosmic 'Whodunit' with Interstellar Forensics". NASA-Hubblesite. Retrieved 23 March 2018.
  7. ^ "IoW_20200109 - Gaia - Cosmos". www.cosmos.esa.int. Retrieved 2020-01-10.

Further reading edit

Latest models edit

External links edit

January 01, 1970
magellanic, stream, confused, with, magellanic, bridge, stream, high, velocity, clouds, extending, from, large, small, magellanic, clouds, over, through, galactic, south, pole, milky, stream, contains, gaseous, feature, dubbed, leading, stream, sighted, 1965, . Not to be confused with Magellanic Bridge The Magellanic Stream is a stream of high velocity clouds of gas extending from the Large and Small Magellanic Clouds over 100 through the Galactic south pole of the Milky Way The stream contains a gaseous feature dubbed the leading arm 1 The stream was sighted in 1965 and its relation to the Magellanic Clouds was established in 1974 Magellanic StreamObject typeIntergalactic high velocity cloudObservation data Epoch J2000 0 ConstellationDorado Mensa Sculptor Right ascension00h 32mDeclination 30 0 edit on Wikidata Contents 1 Discovery and early observations 2 Models 3 Recent observations 4 See also 5 References 6 Further reading 6 1 Latest models 7 External linksDiscovery and early observations edit nbsp Map of Hubble observations overlaid on LAB survey tracing the origin of the Magellanic Stream 2 In 1965 anomalous velocity gas clouds were found in the region of the Magellanic Clouds The gas stretches for at least 180 degrees across the sky This corresponds to 180 kpc 600 000 ly at an approximate distance of 55 kpc 180 000 ly The gas is very collimated and polar with respect to the Milky Way The velocity range is huge from 400 to 400 km s 1 in reference to Local Standard of Rest and velocity patterns do not follow the rest of the Milky Way Hence it was determined to be a classic high velocity cloud However the gas was not mapped and the connection to the two Magellanic Clouds was not made The Magellanic Stream as such was discovered as a Neutral Hydrogen HI gas feature near the Magellanic Clouds by Wannier amp Wrixon in 1972 3 Its connection to the Magellanic Clouds was made by Mathewson et al in 1974 4 Owing to the closeness of the Magellanic Clouds and the ability to resolve individual stars and their parallaxes and proper motion subsequent observations gave the full 6 dimensional phase space information of both clouds with very large relative errors for the transverse velocities This enabled the calculation of the likely past orbit of the Large and the Small Magellanic Cloud in relation to the Milky Way The calculation necessitated large assumptions for example on the shapes and masses of the 3 galaxies and the nature of dynamical friction between the moving objects Observations of individual stars revealed details of star formation history Models editModels describing the formation of the Magellanic Stream had been produced since 1980 Following computing power the initial models were very simple non self gravitating and with few particles Most models predicted a feature leading the Magellanic Clouds These early models were tidal models Just like tides on Earth are induced by the gravity of the leading Moon the models predicted two directions opposite each other in which particles are preferentially pulled However the predicted features were not observed This led to a few models that did not require a leading element but which had problems of their own In 1998 a study analysing the full sky survey made by the HIPASS team at Parkes Observatory generated important new observational data Putman et al discovered that a mass of high velocity clouds leading the Magellanic Clouds was actually fully connected to the Magellanic Clouds So the leading arm feature had its existence finally established Furthermore Lu et al 1998 and Gibson et al 2000 established the chemical similarity between the streams and Magellanic Clouds Newer increasingly sophisticated models all tested the Leading Arm Feature hypothesis These models make heavy use of gravity effects through tidal fields Some models also rely on ram pressure stripping as a shaping mechanism Most recent models increasingly include drag from the halo of the Milky Way as well as gas dynamics star formation and chemical evolution It is thought that the tidal forces mostly affect the Small Magellanic Cloud since it has lower mass and is less gravitationally bound In contrast ram pressure stripping mostly affects the Large Magellanic Cloud because it has a larger reservoir of gas Recent observations edit nbsp Leading arm of the Magellanic Stream measured by Hubble 5 In 2018 research confirmed that the chemical composition of the gas in the Magellanic Stream Leading Arm more closely resembles the composition of the Small Magellanic Cloud rather than the Large Magellanic Cloud by looking at light from background quasars shining through the Stream and analysing the spectrum of light that is either absorbed by or let through it 6 This analysis confirmed that the gas most likely originated from the Small Magellanic Cloud thereby indicating that the Large Magellanic Cloud is winning in the gravity tug of both Clouds working on the Magellanic Stream In 2019 astronomers discovered the young star cluster Price Whelan 1 using Gaia data The star cluster has a low metallicity and belongs to the leading arm of the Magellanic Clouds The discovery of this star cluster suggests that the leading arm of the Magellanic Clouds is 90 000 light years away from the Milky Way only half as far from the Milky Way as previously thought The star cluster is relatively young which is a sign of recent star formation in the leading arm 7 See also editInterstellar cloud List of stellar streams Price Whelan 1References edit Nidever David L Majewski Steven R Burton W Butler 20 May 2008 The Origin of the Magellanic Stream and Its Leading Arm The Astrophysical Journal 679 1 432 459 arXiv 0706 1578 Bibcode 2008ApJ 679 432N doi 10 1086 587042 S2CID 13399751 Hubble finds source of Magellanic Stream ESA Hubble Press Release Retrieved 14 August 2013 Wannier P Wrixon G T May 1972 An Unusual High Velocity Hydrogen Feature The Astrophysical Journal 173 L119 L123 Bibcode 1972ApJ 173L 119W doi 10 1086 180930 Mathewson D S Cleary M N Murray J D June 1974 The Magellanic Stream The Astrophysical Journal 190 291 296 Bibcode 1974ApJ 190 291M doi 10 1086 152875 Hubble measures content of the leading arm of the Magellanic Stream www spacetelescope org Retrieved 4 April 2018 Hubble Solves Cosmic Whodunit with Interstellar Forensics NASA Hubblesite Retrieved 23 March 2018 IoW 20200109 Gaia Cosmos www cosmos esa int Retrieved 2020 01 10 Further reading edit NAME Magellanic Stream SIMBAD Centre de donnees astronomiques de Strasbourg Discovery Wannier P Wrixon G T 1972 An Unusual High Velocity Hydrogen Feature The Astrophysical Journal 173 L119 L123 Bibcode 1972ApJ 173L 119W doi 10 1086 180930 MC connection made Mathewson D S Cleary M N Murray J D 1974 The Magellanic stream The Astrophysical Journal 190 291 296 Bibcode 1974ApJ 190 291M doi 10 1086 152875 Initial modelling Murai T Fujimoto M 1980 The Magellanic Stream and the Galaxy with a Massive Halo Publications of the Astronomical Society of Japan 32 581 604 Bibcode 1980PASJ 32 581M LAF discovery Putman M E et al 1998 Tidal disruption of the Magellanic Clouds by the Milky Way Nature 394 6695 752 754 arXiv astro ph 9808023 Bibcode 1998Natur 394 752P doi 10 1038 29466 S2CID 4357485 Latest models edit Yoshizawa Akira M Noguchi Masafumi 2003 The dynamical evolution and star formation history of the Small Magellanic Cloud effects of interactions with the Galaxy and the Large Magellanic Cloud Monthly Notices of the Royal Astronomical Society 339 4 1135 1154 Bibcode 2003MNRAS 339 1135Y doi 10 1046 j 1365 8711 2003 06263 x Mastropietro C Moore B Mayer L Wadsley J Stadel J 2005 The gravitational and hydrodynamical interaction between the Large Magellanic Cloud and the Galaxy Monthly Notices of the Royal Astronomical Society 363 2 509 520 arXiv astro ph 0412312 Bibcode 2005MNRAS 363 509M doi 10 1111 j 1365 2966 2005 09435 x S2CID 5864290 Connors Tim W Kawata Daisuke Gibson Brad K 2006 N body simulations of the Magellanic Stream Monthly Notices of the Royal Astronomical Society 371 1 108 120 arXiv astro ph 0508390 Bibcode 2006MNRAS 371 108C doi 10 1111 j 1365 2966 2006 10659 x S2CID 15563258 External links editThe Magellanic Stream Astronomy Picture of the Day 25 January 2010 Retrieved from https en wikipedia org w index php title Magellanic Stream amp oldid 1154750998, wikipedia, wiki, book, books, library,

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