The Tilt of the Fundamental Plane: Three-Quarters Structural Nonhomology, One-Quarter Stellar Population

Trujillo, I.; Burkert, A.; Bell, Eric. F.
Bibliographical reference

The Astrophysical Journal, Volume 600, Issue 1, pp. L39-L42.

Advertised on:
1
2004
Number of authors
3
IAC number of authors
0
Citations
134
Refereed citations
124
Description
The variation of the mass-to-light M/L ratios of early-type galaxies as a function of their luminosities L is investigated. It is shown that the tilt β=0.27 (in the B band) of the fundamental plane relation M/L~Lβ can be understood as a combination of two effects: about one-quarter (i.e., Δβ=0.07) is a result of systematic variations of the stellar population properties with increasing luminosity. The remaining three-quarters (i.e., Δβ=0.2) can be completely attributed to nonhomology effects that lead to a systematic change of the surface brightness profiles with increasing luminosity. Consequently, the observed tilt in the K band (β=0.17), where stellar population effects are negligible, is explained by nonhomology effects alone. After correcting for nonhomology, the mean value of the mass-to-light ratio of elliptical galaxies (M/LB) is 7.1+/-2.8 (1 σ scatter).