1998/09/24 by Duncan A. Forbes, Duncan Forbes, T. J. Ponman +3 · 6 citations
Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Demography #Elliptical galaxy #Fundamental plane (elliptical galaxies) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Lenticular galaxy #Peculiar galaxy #Physics #Population #Redshift #Star formation #Stellar population #Stellar, planetary, and galactic studies #Surface brightness #Surface brightness fluctuation #astro-ph
paper · pdf · doi:10.1086/311715
14 pages, Latex, 2 figures, accepted by ApJ Letters
arxiv created 1998/09/24 · openalex publication_date 1998/11/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The fundamental plane (FP) has an intrinsic scatter that cannot be explained purely by observational errors. Using the recently available age estimates for nearby early-type galaxies, we show that a galaxy's position relative to the FP depends on its age. In particular, the mean FP corresponds to elliptical galaxies with an age of ~10 Gyr. Younger galaxies are systematically brighter, with a higher surface brightness relative to the mean relation. Old elliptical galaxies form an "upper envelope" to the FP. For our sample of mostly noncluster galaxies, age can account for almost half of the scatter in the B -band FP. Distance determinations based on the FP may have a systematic bias, if the mean age of the sample varies with redshift. We also show that fundamental plane residuals, B - V colors, and Mg 2 line strength are consistent with an ageing central burst superposed on an old stellar population. This reinforces the view that these age estimates are tracing the last major episode of star formation induced by a gaseous merger event. We briefly discuss the empirical "evolutionary tracks" of merger remnants and young elliptical galaxies in terms of their key observational parameters.