2009/03/23 by Francesco Shankar, Mariangela Bernardi · 56 citations
Environmental Science · Physics and Astronomy · #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Elliptical galaxy #Fundamental plane (elliptical galaxies) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy group #Lenticular galaxy #Luminous infrared galaxy #Peculiar galaxy #Physics #Plant Water Relations and Carbon Dynamics #Star formation #Stellar mass #Velocity dispersion #astro-ph.CO
paper · pdf · doi:10.1111/j.1745-3933.2009.00665.x
published in Monthly Notices of the Royal Astronomical Society Letters 396(1), L76-L80 (Oxford University Press) · Accepted by MNRAS Letter
arxiv created 2009/03/23 · openalex publication_date 2009/05/11 · arxiv updated 2015/05/13 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract We use a sample of about 48000 Sloan Digital Sky Survey early-type galaxies to show that older galaxies have smaller half-light radii Re and larger velocity dispersions σ than younger ones of the same stellar mass Mstar. We use the age-corrected luminosity Lcorrr as a proxy for Mstar to minimize biases: below Lcorrr∼ 1011L⊙, galaxies with age ∼11 Gyrs have Re smaller by 40 per cent and σ larger by 25 per cent, compared to galaxies that are 4 Gyr younger. The sizes and velocity dispersions of more luminous galaxies vary by less than 15 per cent, whatever their age, a challenge for current galaxy formation models. A closer check reveals that the lowering in the dispersion is caused by older galaxies that show a significant departure from the Re−Lcorrr and σ−Lcorrr relations at high Lcorrr. Such features might find an explanation in models where more massive galaxies undergo more minor mergers than less massive galaxies at late times, thus causing a break in the homology. In terms of the Fundamental Plane of early-type galaxies, the data indicate that all galaxies show a significant and similar increase in the dynamical-to-stellar mass ratio with increasing mass, independent of their age. However, older galaxies have smaller Mdyn/Mstar ratios than objects which formed more recently. These findings may suggest that lower mass galaxies and, at fixed stellar mass, higher redshift galaxies, formed from gas-richer progenitors, thus underwent more dissipation and contraction.