{"paper":{"title":"The Hubble Space Telescope Survey of M31 Satellite Galaxies II. The Star Formation Histories of Ultra-Faint Dwarf Galaxies","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"A. A. Cole, A. Dolphin, A. J. Deason, A. L. Dotter, A. McConnachie, A. M. N. Ferguson, A. Savino, A. Wetzel, D. Mackey, D. R. Weisz, E. D. Skillman, E. J. Tollerud, E. N. Kirby, E. Patel, G. Besla, G. F. Lewis, J. Anderson, J. D. Simon, J. S. Bullock, K. M. Gilbert, M. Boylan-Kolchin, M. C. Cooper, M. C. Geha, M. Fardal, M. Jeon, M. J. Irwin, M. L. M. Collins, N. Kallivayalil, N. Martin, P. Guhathakurta, R. Ibata, R. M. Rich, R. P. van der Marel, S. R. Majewski, S. T. Sohn, T. K. Fritz, T. M. Brown","submitted_at":"2023-05-22T18:00:02Z","abstract_excerpt":"We present the lifetime star formation histories (SFHs) for six ultra-faint dwarf (UFD; $M_V>-7.0$, $ 4.9<\\log_{10}({M_*(z=0)}/{M_{\\odot}})<5.5$) satellite galaxies of M31 based on deep color-magnitude diagrams constructed from \\textit{Hubble Space Telescope} imaging. These are the first SFHs obtained from the oldest main sequence turn-off of UFDs outside the halo of the Milky Way (MW). We find that five UFDs formed at least 50\\% of their stellar mass by $z=5$ (12.6~Gyr ago), similar to known UFDs around the MW, but that 10-40\\% of their stellar mass formed at later times. We uncover one remar"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2305.13360","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/2305.13360/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"}