{"paper":{"title":"The age dependence of the size-stellar mass relation and some implications","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.CO","authors_text":"2-UPENN), Francesco Shankar (1), Mariangela Bernardi (2) (1-MPA","submitted_at":"2009-03-23T21:26:34Z","abstract_excerpt":"We use a sample of about 48,000 SDSS early-type galaxies to show that older galaxies have smaller half-light radii re and larger velocity dispersions sigma than younger ones of the same stellar mass Mstar. We use the age-corrected luminosity Lcorr as a proxy for Mstar to minimize biases: below Lcorr~1e11 Lsun, galaxies with age ~11 Gyrs have re smaller by 40% and sigma larger by 25%, compared to galaxies that are ~4 Gyrs younger. The sizes and velocity dispersions of more luminous galaxies vary by less than 15%, whatever their age, a challenge for current galaxy formation models. A closer chec"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"0903.3964","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}