{"paper":{"title":"Globular clusters in the outer Galactic halo: new HST/ACS imaging of 6 globular clusters and the Galactic globular cluster age-metallicity relation","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["astro-ph.SR"],"primary_cat":"astro-ph.GA","authors_text":"Aaron Dotter (STScI), Ata Sarajedini (UF), Jay Anderson (STScI)","submitted_at":"2011-06-21T20:00:02Z","abstract_excerpt":"Color-magnitude diagrams (CMDs) derived from Hubble Space Telescope (HST) Advanced Camera for Surveys F606W,F814W photometry of 6 globular clusters (GCs) are presented. The six GCs form two loose groupings in Galactocentric distance (Rgc): IC 4499, NGC 6426, and Ruprecht 106 at ~15-20 kpc and NGC 7006, Palomar 15, and Pyxis at ~40 kpc. The CMDs allow the ages to be estimated from the main sequence turnoff in every case. In addition, the age of Palomar 5 (Rgc ~ 18 kpc) is estimated using archival HST Wide Field Planetary Camera 2 V,I photometry. The age analysis reveals the following: IC 4499, "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1106.4307","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"}