Péridier Library Abstract Archive

Abstract No. UT 378

Title: The Fundamental Plane at z = 0.18
Author(s): Inger Jørgensen and Jens Hjorth
Keywords: galaxies: evolution - galaxies: scaling laws - galaxies: stellar content
E-Mail: Inger Jørgensen (to request a full copy of this paper)
Preprint: 9702045 Document source or PostScript
Release date: 02/05/97 10:47:55
Publication status: to appear in the proceedings of the "3rd ESO-VLT Workshop Scaling Relations," eds. da Costa et al.
Comments: 10 pages, 5 figures

We present preliminary results regarding the Fundamental Plane (FP) for galaxies in the two rich clusters Abell 665 and Abell 2218. Both clusters have a redshift of 0.18. We have compared the FP for A665 and A2218, and for the cluster CL0024+16 at z = 0.39, with the FP for the Coma cluster. The scatter around the FP is similar for all four clusters. There may be indications that the slope of the FP is more shallow for the intermediate redshift clusters than for the Coma cluster. More complete samples of galaxies in intermediate redshift clusters are needed to map in detail the possible change of the slope as function of redshift. The mass-to-light (M/L) ratio as measured by the FP changes with redshift. At z = 0.18 the M/L ratio (in Gunn r) is 16±9% smaller than for the Coma cluster. Together with earlier results reported for CL0024+16 this implies that the M/L ratio changes with redshift as Delta log M/L_r ~ -0.4 Delta z. The results presented here are in agreement with passive evolution of a stellar population, which formed at a redshift larger than one. However, the possible presence of more recent bursts of star formation complicates the interpretation of the data.