{"paper":{"title":"Unveiling the dynamics of the ultra-fast outflow in IRAS 13224-3809 with X-ray spectroscopy","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"IRAS 13224-3809 hosts a variable ultra-fast outflow exceeding 0.2c that accelerates rapidly during X-ray flares.","cross_cats":["astro-ph.GA"],"primary_cat":"astro-ph.HE","authors_text":"Alessia Tortosa, Alfredo Luminari, Enrico Piconcelli, Fabrizio Nicastro, Francesco Tombesi, Giorgio Lanzuisi, Luca Zappacosta, Marco Laurenti, Massimo Gaspari, Pierpaolo Cond\\`o, Riccardo Middei, Roberto Serafinelli","submitted_at":"2026-04-29T18:01:02Z","abstract_excerpt":"IRAS 13224-3809 is one of the most intensively studied narrow-line Seyfert 1 galaxies, with a rich literature reporting diverse and sometimes contrasting interpretations of its complex X-ray spectra and variability. Notably, a fast and variable ultra-fast outflow (UFO) was discovered in this source, sparking debate over its nature and driving mechanisms. Motivated by these open questions, we present a systematic, time- and flux-resolved reanalysis of the full 2016 XMM-Newton (1.5 Ms) and NuSTAR (500 ks) datasets, employing careful background treatment and equal-count spectral selections. We un"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We unambiguously confirm the presence of a strong, variable outflow with velocities exceeding 0.2c, and find that models including absorption consistently reveal robust physical trends: a velocity-luminosity correlation of the UFO, persistently large line widths, and no compelling equivalent-width-flux anti-correlation. We also report clear evidence for rapid acceleration of the wind in response to X-ray flares.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the identified absorption features are correctly attributed to a photo-ionized ultra-fast outflow rather than being mimicked by emission or relativistic reflection components, and that the equal-count spectral selections and background treatment do not introduce systematic biases in the fitted trends.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Reanalysis of 2016 XMM-Newton and NuSTAR data confirms a strong variable ultra-fast outflow in IRAS 13224-3809 with velocities >0.2c, velocity-luminosity correlation, rapid flare response, and evidence favoring magnetic over radiative driving.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"IRAS 13224-3809 hosts a variable ultra-fast outflow exceeding 0.2c that accelerates rapidly during X-ray flares.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"41a688dbbb29af563d03c16e08003ed0c8a11323f1f0c501a8542b918576abda"},"source":{"id":"2604.27061","kind":"arxiv","version":1},"verdict":{"id":"a199d36c-6019-497e-8b68-63cccb40df5d","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-07T10:34:24.598342Z","strongest_claim":"We unambiguously confirm the presence of a strong, variable outflow with velocities exceeding 0.2c, and find that models including absorption consistently reveal robust physical trends: a velocity-luminosity correlation of the UFO, persistently large line widths, and no compelling equivalent-width-flux anti-correlation. We also report clear evidence for rapid acceleration of the wind in response to X-ray flares.","one_line_summary":"Reanalysis of 2016 XMM-Newton and NuSTAR data confirms a strong variable ultra-fast outflow in IRAS 13224-3809 with velocities >0.2c, velocity-luminosity correlation, rapid flare response, and evidence favoring magnetic over radiative driving.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the identified absorption features are correctly attributed to a photo-ionized ultra-fast outflow rather than being mimicked by emission or relativistic reflection components, and that the equal-count spectral selections and background treatment do not introduce systematic biases in the fitted trends.","pith_extraction_headline":"IRAS 13224-3809 hosts a variable ultra-fast outflow exceeding 0.2c that accelerates rapidly during X-ray flares."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.27061/integrity.json","findings":[],"available":true,"detectors_run":[{"name":"ai_meta_artifact","ran_at":"2026-05-20T23:34:49.889358Z","status":"completed","version":"1.0.0","findings_count":0},{"name":"doi_compliance","ran_at":"2026-05-19T19:36:49.291602Z","status":"completed","version":"1.0.0","findings_count":0}],"snapshot_sha256":"bea2cc2c5b43c634ad159ad56221b5017a06509f2b93a7e0597be7a4c5da0d2f"},"references":{"count":2,"sample":[{"doi":"","year":2014,"title":"An, H., Madsen, K. K., Westergaard, N. J., et al. 2014, in Society of Photo- Optical Instrumentation Engineers (SPIE) Conference Series, V ol. 9144, Space Telescopes and Instrumentation 2014: Ultravio","work_id":"447c3a0d-1227-48d0-a671-8d56944d4155","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2024,"title":"The code requires an ionizing spectral energy distribution (SED) and parameters describing the physical properties of the absorbing gas","work_id":"847e14b8-9ffa-4b25-ac2c-3f572d3a90a7","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":2,"snapshot_sha256":"5b53281870f20ba554dd6d379287f981cafa0b1a757560a3060c6e854940dbde","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"}