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词条 Gaia Sausage
释义

  1. Components

  2. See also

  3. References

  4. Further reading

  5. External links

The Gaia Sausage is the remains of a dwarf galaxy, the "Sausage Galaxy" or Gaia-Enceladus-Sausage or just Gaia-Enceladus, that merged with the Milky Way about 8 - 11 billion years ago. At least eight globular clusters were added to the Milky Way along with 50 billion solar masses of stars, gas and dark matter.[1] The "Gaia Sausage" is so-called because of the characteristic sausage shape of the population in velocity space, the appearance on a plot of radial versus azimuthal and vertical velocities of stars measured in the Gaia Mission.[1] The stars that have merged with the Milky Way have orbits that are highly radial. The outermost points of their orbits are around 20 kiloparsecs from the galactic centre at what is called the halo break.[2]

Components

The Sausage globular clusters are NGC 1851, NGC 1904, NGC 2298, NGC 2808 (possibly the old galactic core), NGC 5286, NGC 6864, NGC 6779, and NGC 7089.[1]

The stars from this dwarf have eccentricities of about 0.9. Their metallicity is also typically higher than other halo stars, with many with [Fe/H] over -1.7 dex.[2]

The ‘Gaia Sausage’ reconstructed the Milky Way, by puffing up the thin disk to make it a thick disk, whilst the gas it brought into the Milky Way triggered a fresh round of star formation and replenished the thin disk. The debris from the dwarf galaxy provides most of the metal-rich halo.[1]

See also

  • Field of Streams
  • Monoceros Ring
  • Omega Centauri
  • M32p, large galaxy merged into Andromeda Galaxy, responsible for its thick disc and most halo stars

References

1. ^1 2 3 {{cite journal |last1=Myeong |first1=G.C. |last2=Evans |first2=N.W. |last3=Belokurov |first3=V., |last4=Sanders |first4=J.L. |last5=Koposov |first5=S. |title=The Sausage Globular Clusters |date=2018 |language=en|bibcode=2018ApJ...863L..28M |arxiv=1805.00453 |doi=10.3847/2041-8213/aad7f7 }}
2. ^1 {{cite journal |last1=Deason |first1=Alis |last2=Belokurov |first2=Vasily |last3=Koposov |first3=Sergey |last4=Lancaster |first4=Lachlan, |title=Apocenter Pile-Up: Origin of the Stellar Halo Density Break |journal=The Astrophysical Journal |volume=862 |pages=L1 |date=2018 |language=en|bibcode=2018ApJ...862L...1D |arxiv=1805.10288 |doi=10.3847/2041-8213/aad0ee }}

Further reading

  • {{cite journal |title= Co-formation of the disc and the stellar halo |authors= Belokurov, V.; Erkal, D.; Evans, N. W.; Koposov, S. E.; Deason, A. J.; |journal= Monthly Notices of the Royal Astronomical Society |volume= 478 |number= 1 |pages= 611–619 |date= July 2018 |arxiv= 1802.03414 |doi= 10.1093/mnras/sty982 |bibcode= 2018MNRAS.478..611B }}
  • {{cite journal |title= Apocenter Pile-Up: Origin of the Stellar Halo Density Break |authors= Deason, Alis J.; Belokurov, Vasily; Koposov, Sergey E.; Lancaster, Lachlan; |arxiv= 1805.10288 |date= May 2018 |bibcode= 2018ApJ...862L...1D |journal= The Astrophysical Journal Letters |volume= 862 |pages= L1 |doi= 10.3847/2041-8213/aad0ee }}
  • {{cite arxiv |title= The Sausage Globular Clusters |authors= Myeong, G. C.; Evans, N. W.; Belokurov, V.; Sanders, J. L.; Koposov, S. E.; |eprint= 1805.00453|class= astro-ph.GA |date= May 2018 }}
  • {{cite journal |title= The Milky Way Halo in Action Space |authors= Myeong, G. C.; Evans, N. W.; Belokurov, V.; Sanders, J. L.; Koposov, S. E.; |date= April 2018 |arxiv= 1802.03351 |doi= 10.3847/2041-8213/aab613 |bibcode= 2018ApJ...856L..26M |journal= The Astrophysical Journal Letters |volume= 856 |issue= 2 |page= L26 }}
  • {{cite arxiv |title= The Shards of ω Centauri |authors= Myeong, G. C.; Evans, N. W.; Belokurov, V.; Sanders, J. L.; Koposov, S. E.; |eprint= 1804.07050|class= astro-ph.GA |date= April 2018 }}

External links

  • {{youtube|8T2EdRZ_iE4|Gaia Sausage Simulation}}
  • {{cite news |url= https://www.cmu.edu/news/stories/archives/2018/july/gaia-sausage.html |title= The Gaia Sausage: The Major Collision that Changed the Milky Way Galaxy |date= 4 July 2018 |author= Jocelyn Duffy |publisher= Carnegie Mellon University }}
  • {{cite news |url= https://www.cam.ac.uk/research/news/the-gaia-sausage-the-major-collision-that-changed-the-milky-way |title= The Gaia Sausage: the major collision that changed the Milky Way |publisher= University of Cambridge |author= Sarah Collins |date= 4 July 2018 }}
{{Milky Way}}

2 : Milky Way|Dwarf galaxies
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