{"paper":{"title":"The Metallicity Dependence of PAH Emission in Galaxies I: Insights from Deep Radial Spitzer Spectroscopy","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Brandon S. Hensley, Bruce T. Draine, Carl A. Starkey, Cory M. Whitcomb, Daniel A. Dale, Evan D. Skillman, Grant P. Donnelly, J.-D. T. Smith, Karin Sandstrom, Lee Armus, Robert C. Kennicutt, Thomas S.-Y. Lai","submitted_at":"2024-05-15T19:58:03Z","abstract_excerpt":"We use deep Spitzer mid-infrared spectroscopic maps of radial strips across three nearby galaxies with well-studied metallicity gradients (M101, NGC 628, and NGC 2403) to explore the physical origins of the observed deficit of polycyclic aromatic hydrocarbons (PAHs) at sub-solar metallicity (i.e. the PAH-metallicity relation or PZR). These maps allow us to trace the evolution of all PAH features from 5-18 $\\mu$m as metallicity decreases continuously from solar ($Z_\\odot$) to 0.2 $Z_\\odot$. The total PAH to dust luminosity ratio remains relatively constant until reaching a threshold of $\\sim$$\\"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2405.09685","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/2405.09685/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"}