The universal Faber-Jackson relation
Abstract
In the context of modified Newtonian dynamics, the Fundamental Plane, as the observational signature of the Newtonian virial theorem, is defined by high-surface-brightness objects that deviate from being purely isothermal: the line-of-sight velocity dispersion should slowly decline with radius as observed in luminous elliptical galaxies. All high-surface-brightness objects (e.g. globular clusters, ultra-compact dwarfs) will lie, more or less, on the Fundamental Plane defined by elliptical galaxies, but low-surface-brightness objects (dwarf spheroidals) would be expected to deviate from this relation. This is borne out by observations. With Milgrom's modified Newtonian dynamics (MOND), the Faber-Jackson relation (L ~ σ4), ranging from globular clusters to clusters of galaxies and including both high- and low-surface-brightness objects, is the more fundamental and universal scaling relation in spite of its larger scatter. The Faber-Jackson relation reflects the presence of an additional dimensional constant (the MOND acceleration a0) in the structure equation.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2010
- DOI:
- 10.1111/j.1365-2966.2010.16957.x
- arXiv:
- arXiv:1002.2765
- Bibcode:
- 2010MNRAS.407.1128S
- Keywords:
-
- galaxies: elliptical and lenticular;
- cD;
- galaxies: fundamental parameters;
- galaxies: kinematics and dynamics;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 7 pages, 7 figures, revised in response to referee's report, error corrected in Fig. 5, two additional figures, conclusions unchanged. Accepted MNRAS