Baryonic Faber-Jackson relation

For elliptical galaxies, the BFJR is thought to be a projection of the fundamental plane (FP), which includes the stellar half-mass radius as a third variable. We study the BFJR and FP across eight orders of magnitude in baryonic mass, encompassing galaxy groups, ellipticals, dwarf ellipticals, and dwarf spheroidals.

We compile and homogenize data for 1400 pressure-supported systems and measure their mean internal baryonic acceleration <gbar>. We find that the properties of the BFJR and FP systematically depend on the internal acceleration of the sampled systems, with a transition around the acceleration scale a0~=~1.2x10^-10m/s^2^. For low-acceleration systems with <gbar> < 0.6a0 (dwarf galaxies and galaxy groups), the BFJR relation takes the form log10(Mbar/M_{sun}_)=(4.19+/-0.10)log10(siglos/(km/s))+2.55+/-0.16 with an orthogonal intrinsic scatter of 0.11+/-0.01 dex.