{"paper":{"title":"The Demographics of Sagittarius A* X-ray Flares over 25 Years with Chandra","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Chandra's 25-year Sgr A* catalog of 100 X-ray flares shows brighter events have harder spectra.","cross_cats":[],"primary_cat":"astro-ph.HE","authors_text":"Daryl Haggard, Howard A. Smith, Joey Neilsen, Joseph L. Hora, Joseph M. Michail, Mayura Balakrishnan, Michael A. Nowak, Nicole M. Ford, Sebastiano D. von Fellenberg, Sera Markoff, Sophia S\\'anchez-Maes, S. P. Willner, Zach Sumners","submitted_at":"2026-05-13T18:00:02Z","abstract_excerpt":"We present the Chandra 25-year Sagittarius A* (Sgr A*) X-ray flare catalog: a systematic analysis of 6.8 Ms of Sgr A* monitoring spanning the Chandra X-ray Observatory's mission lifetime. This is the most complete Chandra Sgr A* X-ray flare catalog to date, consisting of 100 flares with 2$-$10 keV unabsorbed luminosities ranging from $\\sim$ 4$-$575 $\\times 10^{33}$ erg s$^{-1}$. 18 flares are reported for the first time, including the second brightest Sgr A* flare observed by Chandra. The expanded dataset supports previous indications of a correlation between X-ray flare hardness and luminosit"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The expanded dataset supports previous indications of a correlation between X-ray flare hardness and luminosity. Spectral modeling corroborates this finding, showing a change in the X-ray spectral index, from Γ ∼ 3 to 2 with increasing flare brightness.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"Flare detection relies on accurate background subtraction and chosen count-rate thresholds in the Chandra monitoring data; any systematic bias in these steps would alter the reported sample size, luminosity range, and correlation strengths.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A 25-year Chandra catalog of 100 Sgr A* X-ray flares confirms that brighter flares are spectrally harder and strengthens prior correlations with duration and fluence.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Chandra's 25-year Sgr A* catalog of 100 X-ray flares shows brighter events have harder spectra.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"2aef6f0cf34c2a9b41018ec78679b5719c19c87b1f85352d0f3bcdf819ccbd9a"},"source":{"id":"2605.13962","kind":"arxiv","version":1},"verdict":{"id":"a76d22e8-a38e-4c35-9f21-49b942fc1ca2","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T05:26:47.526040Z","strongest_claim":"The expanded dataset supports previous indications of a correlation between X-ray flare hardness and luminosity. Spectral modeling corroborates this finding, showing a change in the X-ray spectral index, from Γ ∼ 3 to 2 with increasing flare brightness.","one_line_summary":"A 25-year Chandra catalog of 100 Sgr A* X-ray flares confirms that brighter flares are spectrally harder and strengthens prior correlations with duration and fluence.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"Flare detection relies on accurate background subtraction and chosen count-rate thresholds in the Chandra monitoring data; any systematic bias in these steps would alter the reported sample size, luminosity range, and correlation strengths.","pith_extraction_headline":"Chandra's 25-year Sgr A* catalog of 100 X-ray flares shows brighter events have harder spectra."},"references":{"count":60,"sample":[{"doi":"10.1051/0004-6361/201322068","year":1999,"title":"P., Tollerud , E","work_id":"aeafa8f2-1c15-4f27-9682-a76b6bf42e2b","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1038/35092510","year":2001,"title":"Baganoff, F. K., Bautz, M. W., Brandt, W. N., et al. 2001, Nature, 413, 45, doi: 10.1038/35092510","work_id":"674bbbe5-bca1-47a4-bf1e-666a03f84360","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1086/375145","year":2003,"title":"K., Maeda, Y., Morris, M., et al","work_id":"cf805ed6-bea6-4f40-939d-b53d8261dbe5","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1088/0004-637x/802/1/69","year":2015,"title":"archivePrefix = \"arXiv\", eprint =","work_id":"00667e97-46d8-465a-8e45-460acae6f267","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.3847/1538-4357/aaf71f","year":2019,"title":"2019, ApJ, 871, 161, doi: 10.3847/1538-4357/aaf71f","work_id":"e19fcf5b-fb55-4ebf-bcab-23480150666d","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":60,"snapshot_sha256":"d7ad6e0e1db55b1db4841289b8d028b7627104c5c903aea14769dacef8048f06","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"1170f503f97275af64160d78312accb5f578d5a424c3c3dc64aced9145e99206"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}