{"paper":{"title":"Spectroastrometry and Reverberation Mapping of Active Galactic Nuclei. II. Measuring Geometric Distances and Black Hole Masses of Four Nearby Quasars","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["astro-ph.CO"],"primary_cat":"astro-ph.GA","authors_text":"Chen Hu, Daryl J. Santos, Dieter Lutz, Eckhard Sturm, Feng-Na Fang, Frank Eisenhauer, Hao Zhang, Hartmut Winkler, Helmut Feuchtgruber, Hua-Rui Bai, Jes\\'us Aceituno, Jian-Min Wang, Jia-Qi Feng, Jin-Ming Bai, Jinyi Shangguan, Jun-Rong Liu, Linda J. Tacconi, Luis C. Ho, Michael S. Brotherton, Natascha M. F\\\"orster Schreiber, Pu Du, Reinhard Genzel, Ric Davies, Romain G. Petrov, Sebastian Rabien, Shuo Zhai, Stefan Gillessen, Taro Shimizu, Thomas Ott, Yan-Rong Li, Yi-Lin Wang, Yi-Peng Zhao, Yixian Cao, Yi-Xin Fu, Yong-Jie Chen, Yu-Yang Songsheng, Yu Zhao, Zhu-Heng Yao","submitted_at":"2025-02-26T05:54:45Z","abstract_excerpt":"The geometric distances of active galactic nuclei (AGNs) are challenging to measure because of their exceptionally compact structure yet vast cosmic distances. A combination of spectroastrometry and reverberation mapping (SARM) of broad-line regions (BLRs) constitutes a novel means to probe the geometric distance of AGNs, which has recently become practically feasible owing to successful interferometric observations with VLTI/GRAVITY. Here, we perform SARM analysis of four nearby quasars: Mrk 509, PDS 456, 3C 273, and NGC 3783. Results for the former two are reported for the first time and the"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2502.18856","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/2502.18856/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"}