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Sagittarius Stream

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Long and elongated structure of stars

Inastronomy, theSagittarius Stream is a long, complex structure made ofstars that wrap around theMilky Way Galaxy in anorbit that nearly crosses thegalactic poles. It consists oftidally stripped stars from theSagittarius Dwarf Elliptical Galaxy, resulting from the process ofmerging with the Milky Way over a period of billions of years.

This stellar stream was originally proposed in 1995 byDonald Lynden-Bell after analyzing the distribution ofglobular clusters in the Milky Way.^[1] The actual structure was identified by Newberg and associates (2002)^[2] plus Majewski and associates (2003)^[3] using data from the2MASS andSDSS surveys. In 2006, Belokurov and his collaborators^[4] found that the Sagittarius Stream has two branches.

When the progenitor object was shredded apart during the interaction, it sent oscillations (analogous to sound waves) through the Milky Wayspiral arm structure. The effects of the oscillations are observed today as layers of alternately denser and sparserstar distributions, above and below theSolar System. Presently, the position of the Sagittarius Stream relative to the observed layers^[5] make the Sagittarius Dwarf Elliptical Galaxy the strongest candidate for this intruding object.

References

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^Lynden-Bell, R. M.; Lynden-Bell, D. (July 1995)."Ghostly streams from the formation of the Galaxy's halo".Monthly Notices of the Royal Astronomical Society.275 (2):429–442.Bibcode:1995MNRAS.275..429L.doi:10.1093/mnras/275.2.429.
^Newberg, Heidi Jo; et al. (April 2002). "The Ghost of Sagittarius and Lumps in the Halo of the Milky Way".The Astrophysical Journal.569 (1):245–274.arXiv:astro-ph/0111095.Bibcode:2002ApJ...569..245N.doi:10.1086/338983.S2CID 16909562.
^Majewski, Steven R.; et al. (December 2003). "A Two Micron All Sky Survey View of the Sagittarius Dwarf Galaxy. I. Morphology of the Sagittarius Core and Tidal Arms".The Astrophysical Journal.599 (2):1082–1115.arXiv:astro-ph/0304198.Bibcode:2003ApJ...599.1082M.doi:10.1086/379504.S2CID 2387702.
^Belokurov, V.; et al. (May 2006). "The Field of Streams: Sagittarius and Its Siblings".The Astrophysical Journal.642 (2):L137 –L140.arXiv:astro-ph/0605025.Bibcode:2006ApJ...642L.137B.doi:10.1086/504797.S2CID 1774643.
^Yanny, Brian; Gardner, Susan (Sep 2013). "The Stellar Number Density Distribution in the Local Solar Neighborhood is North-South Asymmetric".The Astrophysical Journal.777 (2): 91.arXiv:1309.2300.Bibcode:2013ApJ...777...91Y.doi:10.1088/0004-637X/777/2/91.S2CID 118314811.

External links

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Deriving The Shape Of The Galactic Stellar Disc (SkyNightly) March 17, 2006
Deriving the shape of the Galactic stellar disc, A&A press release, March 16, 2006

Milky Way

Location

Milky Way →Milky Way subgroup →Local Group→Local Sheet→Local Volume→Virgo Supercluster→Laniakea Supercluster →Pisces–Cetus Supercluster Complex →Local Hole →Observable universe →Universe
Each arrow (→) may be read as "within" or "part of".

Structure

Galactic Center	Sagittarius A Sagittarius A* Fermi bubbles Supermassive black hole Galactic Center filaments Galactic Center GeV excess Galactic Center Radio Arc
Disk	Carina–Sagittarius Norma–Cygnus Orion–Cygnus Perseus Scutum–Centaurus Near 3 kpc Arm Far 3 kpc Arm
Halo	Aquarius Stream Fimbulthul stream Gaia Sausage Helmi stream Magellanic Stream Monoceros Ring Palomar 5 stream Pisces–Eridanus stream Sagittarius Stream Virgo Stream

Satellite
galaxies

Magellanic Clouds	Large Magellanic Cloud Small Magellanic Cloud Magellanic Bridge
Dwarfs	Antlia II Boötes I Boötes II Boötes III Canes Venatici I Canes Venatici II Canis Major Carina Coma Berenices Crater 2 Draco Eridanus II Fornax Hercules Leo I Leo II Leo IV Leo V Leo T Phoenix Pisces Overdensity Pisces II Reticulum II Sagittarius Spheroidal Segue 1 Segue 2 Sculptor Sextans Triangulum II Ursa Major I Ursa Major II Ursa Major III Ursa Minor Virgo I Willman 1