{"paper":{"title":"ALMA Band 2 line survey of a $z = 3.44$ clumpy strongly-lensed submillimetre galaxy","license":"http://creativecommons.org/licenses/by/4.0/","headline":"ALMA Band 2 observations of a lensed galaxy at z=3.44 detect multiple molecular lines that trace highly excited dense gas bathed in intense far-ultraviolet radiation.","cross_cats":[],"primary_cat":"astro-ph.GA","authors_text":"Tom J. L. C. Bakx","submitted_at":"2026-04-01T16:16:21Z","abstract_excerpt":"I present the first molecular line survey of the strongly lensed submillimetre galaxy SPT-S J002706-5007.4 ($z = 3.44$) using the new Atacama Large Millimeter/submillimeter Array (ALMA) Band~2 receivers (67 - 116 GHz), whose commissioning completes ALMA's full (sub-)millimetre frequency coverage. The broad spectral coverage from 76 to 111 GHz of the observations simultaneously accesses a large suite of molecular and atomic emission lines. I report the novel detections of the lines that were hitherto inaccessible at $z = 3.44$, CO (3-2) and HNC (4-3), as well as detections of previously-observe"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The CO spectral line energy distribution and [CI]/CO line ratios indicate highly excited, dense molecular gas with a strong far-ultraviolet radiation field. The dense gas fraction is estimated at 17 ± 9 per cent.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The interpretation of line ratios as tracers of excitation and density assumes that differential lensing and beam-filling factors do not significantly alter the observed line ratios across the 76-111 GHz band.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"ALMA Band 2 observations of SPT-S J002706-5007.4 at z=3.44 detect multiple molecular lines indicating highly excited dense gas and demonstrate the band's utility for high-redshift spectroscopy.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"ALMA Band 2 observations of a lensed galaxy at z=3.44 detect multiple molecular lines that trace highly excited dense gas bathed in intense far-ultraviolet radiation.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"bed0abd7a8ca2c357e6aec8a5ffc0acc86f2903715e5417aba754f42844f15f0"},"source":{"id":"2604.01089","kind":"arxiv","version":2},"verdict":{"id":"bbac28ef-2b03-4709-8594-396ba5ff0bbf","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-19T17:52:52.677223Z","strongest_claim":"The CO spectral line energy distribution and [CI]/CO line ratios indicate highly excited, dense molecular gas with a strong far-ultraviolet radiation field. The dense gas fraction is estimated at 17 ± 9 per cent.","one_line_summary":"ALMA Band 2 observations of SPT-S J002706-5007.4 at z=3.44 detect multiple molecular lines indicating highly excited dense gas and demonstrate the band's utility for high-redshift spectroscopy.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The interpretation of line ratios as tracers of excitation and density assumes that differential lensing and beam-filling factors do not significantly alter the observed line ratios across the 76-111 GHz band.","pith_extraction_headline":"ALMA Band 2 observations of a lensed galaxy at z=3.44 detect multiple molecular lines that trace highly excited dense gas bathed in intense far-ultraviolet radiation."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.01089/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":2,"sample":[{"doi":"10.48550/arxiv.2211.00195","year":2014,"title":"Physics and Chemistry of Star Formation: The Dynamical ISM Across Time and Spatial Scales , year = 2023, editor =","work_id":"58e206da-d3fe-4654-9f22-d968086dc194","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1117/12.2629766","year":1998,"title":"Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumenta- tion for Astronomy XI. p. 121900K, doi:10.1117/12.2629766 Hughes D. H., et al., 1998, Nature, 394, 241 Imanishi M., Nakanishi K.,","work_id":"838eac25-13ea-42d7-8533-95fff2eee350","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":2,"snapshot_sha256":"f47a29f6c99dc89db2956f6f17743a06e6eaaa74bbe3ed34e360a640ff40c81c","internal_anchors":0},"formal_canon":{"evidence_count":2,"snapshot_sha256":"6d2ecb4c7890178d92003eb05b4f45de084aacaf9cd2a31c2bac21835d4f7e10"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}