Universality of galactic surface densities within one dark halo scale-length
Abstract
It was recently discovered that the mean dark matter surface density within one dark halo scale-length (the radius within which the volume density profile of dark matter remains approximately flat) is constant across a wide range of galaxies. This scaling relation holds for galaxies spanning a luminosity range of 14 magnitudes and the whole Hubble sequence. Here we report that the luminous matter surface density is also constant within one scale-length of the dark halo. This means that the gravitational acceleration generated by the luminous component in galaxies is always the same at this radius. Although the total luminous-to-dark matter ratio is not constant, within one halo scale-length it is constant. Our finding can be interpreted as a close correlation between the enclosed surface densities of luminous and dark matter in galaxies.
- Publication:
-
Nature
- Pub Date:
- October 2009
- DOI:
- 10.1038/nature08437
- arXiv:
- arXiv:0909.5203
- Bibcode:
- 2009Natur.461..627G
- Keywords:
-
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology
- E-Print:
- Accepted as a Letter to Nature