Categories
  Encyclosphere.org ENCYCLOREADER
  supported by EncyclosphereKSF

Density contrast

From HandWiki - Reading time: 1 min


Density contrast is a parameter used in galaxy formation to indicate where there are local enhancements in matter density.[1]

Δ=ϱϱ

It is believed that after inflation, although the universe was mostly uniform, some regions were slightly denser than others with contrast densities on the order of 1 trillionth. As the horizon distance expanded, the enclosed causally connected (i.e. gravitationally connected) masses increased until they reached the Jeans mass and began to collapse, which allowed galaxies, galaxy clusters, superclusters, and filaments to form.

References

  1. Gramann, Mirt; Einasto, Maret; Heinämäki, Pekka; Teerikorpi, Pekka; Saar, Enn; Nurmi, Pasi; Einasto, Jaan (2015-09-01). "Characteristic density contrasts in the evolution of superclusters. The case of A2142 supercluster" (in en). Astronomy & Astrophysics 581: A135. doi:10.1051/0004-6361/201526768. ISSN 0004-6361. Bibcode2015A&A...581A.135G. https://www.aanda.org/articles/aa/abs/2015/09/aa26768-15/aa26768-15.html. 





Licensed under CC BY-SA 3.0 | Source: https://handwiki.org/wiki/Astronomy:Density_contrast
26 views |
↧ Download this article as ZWI file
Encyclosphere.org EncycloReader is supported by the EncyclosphereKSF