{"paper":{"title":"$R_{\\rm e}$. I. Understanding galaxy sizes, associated luminosity densities, and the artificial division of the early-type galaxy population","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Alister W. Graham","submitted_at":"2019-09-11T06:21:49Z","abstract_excerpt":"The deceptive simplicity of the radius enclosing an arbitrary 50 percent of a galaxy's light has hamstrung the understanding of early-type galaxies (ETGs). Half a century ago, using the \"effective half-light radii\" $R_e$ from de Vaucouleurs' $R^{1/4}$ model, S\\'ersic reported that bright ETGs follow the relation $\\mathfrak{M}_B\\propto2.5\\log R_e$; and consequently one has that $\\langle\\mu\\rangle_e\\propto2.5\\log R_e$ and $\\mu_e\\propto2.5\\log R_e$, where $\\mu_e$ and $\\langle\\mu\\rangle_e$ are the effective surface brightness at $R_e$ and the mean effective surface brightness within $R_e$, respect"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1909.04867","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/1909.04867/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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"}