{"paper":{"title":"Horizon-scale tests of gravity theories and fundamental physics from the Event Horizon Telescope image of Sagittarius A$^*$","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"The Event Horizon Telescope image of Sagittarius A* imposes tight limits on gravity models that predict larger black hole shadows than in general relativity.","cross_cats":["astro-ph.HE","hep-ph","hep-th"],"primary_cat":"gr-qc","authors_text":"Ali \\\"Ovg\\\"un, Alireza Allahyari, Cosimo Bambi, Dipanjan Dey, Kimet Jusufi, Luca Visinelli, Misba Afrin, Mohsen Khodadi, Pankaj S. Joshi, Parth Bambhaniya, Rahul Kumar Walia, Rittick Roy, Sunny Vagnozzi, Sushant G. Ghosh, Yu-Dai Tsai","submitted_at":"2022-05-16T16:22:56Z","abstract_excerpt":"Horizon-scale images of black holes (BHs) and their shadows have opened an unprecedented window onto tests of gravity and fundamental physics in the strong-field regime. We consider a wide range of well-motivated deviations from classical General Relativity (GR) BH solutions, and constrain them using the Event Horizon Telescope (EHT) observations of Sagittarius A$^*$ (Sgr A$^*$), connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of Sgr A$^*$'s mass-to-distance ratio. The scenarios we consider, and whose fundamental"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"the EHT image of Sgr A* places particularly stringent constraints on models predicting a shadow size larger than that of a Schwarzschild BH of a given mass, with the resulting limits in some cases surpassing cosmological ones","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of Sgr A*'s mass-to-distance ratio","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"EHT observations of Sgr A* constrain deviations from GR black hole solutions including regular BHs, string-inspired spacetimes, and BH mimickers, with some limits exceeding cosmological bounds.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"The Event Horizon Telescope image of Sagittarius A* imposes tight limits on gravity models that predict larger black hole shadows than in general relativity.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"bf307d0b14262257bcf69900e7548de19c11c71dc82e0a25b3769cb720e1918c"},"source":{"id":"2205.07787","kind":"arxiv","version":3},"verdict":{"id":"6ce41acd-c74a-4635-9b1c-015596f82a28","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-16T11:16:04.606684Z","strongest_claim":"the EHT image of Sgr A* places particularly stringent constraints on models predicting a shadow size larger than that of a Schwarzschild BH of a given mass, with the resulting limits in some cases surpassing cosmological ones","one_line_summary":"EHT observations of Sgr A* constrain deviations from GR black hole solutions including regular BHs, string-inspired spacetimes, and BH mimickers, with some limits exceeding cosmological bounds.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"connecting the size of the bright ring of emission to that of the underlying BH shadow and exploiting high-precision measurements of Sgr A*'s mass-to-distance ratio","pith_extraction_headline":"The Event Horizon Telescope image of Sagittarius A* imposes tight limits on gravity models that predict larger black hole shadows than in general relativity."},"references":{"count":300,"sample":[{"doi":"","year":2020,"title":"de Cesare and V","work_id":"67103ec7-4892-4e42-bdf4-493a4bd67fb4","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2021,"title":"D. Benisty, M. Chaichian, and M. Oksanen, (2021), arXiv:2107.12161 [gr-qc]","work_id":"e0491e2a-6be9-432f-879c-bfe50ac610f4","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2022,"title":"S. A. H. Mansoori, A. Talebian, Z. Molaee, and H. Firouzjahi, Phys. Rev. D 105, 023529 (2022), arXiv:2108.11666 [gr-qc]","work_id":"eb491e4b-087c-4ce2-8242-253d2de3168a","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2022,"title":"G. G. L. Nashed and E. N. Saridakis, (2022), arXiv:2206.12256 [gr-qc]. 69","work_id":"4a0ebb41-8e14-44ca-9e01-2ec48983b145","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":2022,"title":"P. Jirouˇ sek, K. Shimada, A. Vikman, and M. Yam- aguchi, JCAP 11, 019 (2022), arXiv:2207.12611 [gr- qc]","work_id":"e31e194f-2961-4a02-8c87-1d7c5704c334","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":300,"snapshot_sha256":"4d34139dea307b3bb08fcf6ce5ff0c861bcfa792bff3d5ff220d5a8f7c86a6f4","internal_anchors":139},"formal_canon":{"evidence_count":2,"snapshot_sha256":"e88359e556ec99a351a593ea90a25a6745c9328ad9d3a3ef8e3e4050cacb46ed"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}