Tully-Fisher relation
This is an old revision of this page, as edited by AK (talk | contribs) at 19:31, October 3, 2012. It may differ significantly from current revision.
The Tully-Fisher relation or The Tully-Fisher law is expression of observations showing that for disk galaxies the fourth power of the circular velocity of stars around the core of the galaxy is proportional to the luminosity L.
The Tully-Fisher relation and halo dark matter
Since L is proportional to the mass M of the galaxy, it follows that the fourth power of the circular velocity is proportional to M. Newtonian mechanics, however, states that the square of the circular velocity is proportional to M. In order to rectify this discrepancy, astronomers assume the existence of halo dark matter.[1]
References
- ↑ Silvia Behar, Moshe Carmeli (19 Jul 1999). Derivation of the Tully-Fisher Law from General Relativity Theory: Doubts about the Existence of Halo Dark Matter 1397-1404.