{"paper":{"title":"4MOST ChANGES: Catalog of high-redshift quasar candidates (4.5 < $z$ < 7) selected with SED fitting","license":"http://creativecommons.org/licenses/by/4.0/","headline":"A catalog of 6104 high-redshift quasar candidates at 4.5 < z < 7 is assembled from southern-sky multi-band photometry using SED fitting.","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"A. Rojas-Lilay\\'u, A. Upadhyayula, C. Mazzucchelli, D. Stern, E. P. Farina, F. E. Bauer, G. Papini, J. A. Acevedo Barroso, L. N. Mart\\'inez-Ram\\'irez, M. J. Temple, R. J. Assef, S. Belladitta, S. Satheesh-Sheeba, T. Mkrtchyan, V. Toptun","submitted_at":"2026-04-14T18:01:33Z","abstract_excerpt":"The identification of high-redshift quasars ($z > 4.5$) is critical for studying the early Universe, supermassive black hole growth, and cosmic reionization. Most known high-redshift quasars are located in the northern hemisphere, leaving the southern sky largely unexplored. As part of the 4-meter Multi-Object Spectroscopic Telescope (4MOST) and Chilean AGN/Galaxy Extragalactic Survey (ChANGES) S1604 survey, we aim to create a large catalog of high-redshift quasar candidates in the southern hemisphere using multiwavelength photometry and Spectral Energy Distribution (SED) fitting, with the goa"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"Our final catalog contains 6104 high-redshift quasar candidates within 4.5 < z < 7, with detections in 7 or more photometric bands satisfying our SED-based selection criteria (BIC > 0 and F-test > 10). Spectroscopic validation using NTT/EFOSC2 and Palomar/NGPS confirmed 3 high-redshift quasars at z > 5 out of 6 observed candidates.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the chosen quasar and brown dwarf SED templates, combined with the specific statistical thresholds (BIC > 0, F-test > 10) and minimum band requirement, reliably identify true high-redshift quasars with low contamination from other sources in the photometric data.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"A catalog of 6104 high-redshift quasar candidates (4.5 < z < 7) in the southern hemisphere was produced via multiwavelength photometry and SED fitting, with spectroscopic confirmation of three objects at z > 5.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A catalog of 6104 high-redshift quasar candidates at 4.5 < z < 7 is assembled from southern-sky multi-band photometry using SED fitting.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"8d6fc4582f511ea0ce048c4a05369db7af6dd986ff8332edebcbc4aa8b061e4a"},"source":{"id":"2604.13178","kind":"arxiv","version":1},"verdict":{"id":"02c75ede-d1ec-4a5a-9f4c-24bf4d72f082","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T14:40:15.260338Z","strongest_claim":"Our final catalog contains 6104 high-redshift quasar candidates within 4.5 < z < 7, with detections in 7 or more photometric bands satisfying our SED-based selection criteria (BIC > 0 and F-test > 10). Spectroscopic validation using NTT/EFOSC2 and Palomar/NGPS confirmed 3 high-redshift quasars at z > 5 out of 6 observed candidates.","one_line_summary":"A catalog of 6104 high-redshift quasar candidates (4.5 < z < 7) in the southern hemisphere was produced via multiwavelength photometry and SED fitting, with spectroscopic confirmation of three objects at z > 5.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the chosen quasar and brown dwarf SED templates, combined with the specific statistical thresholds (BIC > 0, F-test > 10) and minimum band requirement, reliably identify true high-redshift quasars with low contamination from other sources in the photometric data.","pith_extraction_headline":"A catalog of 6104 high-redshift quasar candidates at 4.5 < z < 7 is assembled from southern-sky multi-band photometry using SED fitting."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.13178/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":91,"sample":[{"doi":"","year":2018,"title":"Abbott, T. 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B., Allam, S., et al. 2018, ApJS, 239, 18","work_id":"caa9f9cd-c32c-4e01-be53-afe814922f0e","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2020,"title":"2020, ApJS, 249, 3","work_id":"742e9e4e-a4ac-47c9-9246-3000749769b6","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2007,"title":"F., Homeier, D., et al","work_id":"ca1a5c03-8418-4a6f-9993-34d15acfa984","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2018,"title":"J., Stern, D., Noirot, G., et al","work_id":"25a399b9-9151-42ad-8889-c0441407fc6e","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2023,"title":"E., Lira, P., Anguita, T., et al","work_id":"f55a95da-257e-431c-a65d-4f8b4bad7c86","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":91,"snapshot_sha256":"b53376c9b928635a202a4685505c09761bb25b10ed456958033ac397870cf862","internal_anchors":1},"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"}