{"paper":{"title":"A spectroscopic study of blue supergiant stars in the Sculptor galaxy NGC 55: chemical evolution and distance","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Fabio Bresolin, Grzegorz Pietrzynski, I-Ting Ho, Miguel Urbaneja, Norberto Castro, Norbert Przybilla, Rolf Kudritzki, Wolfgang Gieren","submitted_at":"2016-07-14T21:21:48Z","abstract_excerpt":"Low resolution (4.5 to 5 Angstroem) spectra of 58 blue supergiant stars distributed over the disk of the Magellanic spiral galaxy NGC 55 in the Sculptor group are analyzed by means of non-LTE techniques to determine stellar temperatures, gravities and metallicities (from iron peak and alpha-elements). A metallicity gradient of -0.22 +/- 0.06$ dex/R_25 is detected. The central metallicity on a logarithmic scale relative to the Sun is [Z] = -0.37 +\\- 0.03. A chemical evolution model using the observed distribution of stellar and interstellar medium gas mass column densities reproduces the observ"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1607.04325","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"}