{"paper":{"title":"HST/ACS Direct Ages of the Dwarf Elliptical Galaxies NGC 147 and NGC 185","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"A. Dolphin, A. Grocholski, D. Weisz, M. Geha, P. Guhathakurta, R. P. van der Marel","submitted_at":"2015-03-23T04:26:29Z","abstract_excerpt":"We present the deepest optical photometry for any dwarf elliptical (dE) galaxy based on Hubble Space Telescope ACS observations of the Local Group dE galaxies NGC 147 and NGC 185. The resulting F606W and F814W color-magnitude diagrams are the first to reach below the main sequence turnoff in a dE galaxy, allowing us to determine full star formation histories in these systems. The ACS fields are located ~1.5 effective radii from the galaxy center to avoid photometric crowding. While our ACS pointings in both dEs show unambiguous evidence for old and intermediate age stars, the mean age in NGC 1"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1503.06526","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"}