{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"3b0fe0937f1ffc85dd650dfbf2feef87280fe16a1bcc43aab51810632d19c7d6","created":"2026-10-03T07:17:54Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"57404604b0428576bce13a457ae53de550ffc66481fb92239fa1821b3ea6f276","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"astro.first-smbh.imbh-occupation","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Black holes between a hundred and a hundred thousand solar masses (intermediate-mass black holes) should be leftovers of the seeds that grew into giant black holes. How many small galaxies and star clusters contain one today records which kind of seed was common.","posed_since":"","precise":"Measure the occupation fraction $f_{\\mathrm{occ}}(M_*)$ of black holes with $M_{\\mathrm{BH}} \\sim 10^2-10^5\\ M_{\\mathrm{sun}}$ in galaxies with $M_* \\sim 10^7-10^10\\ M_{\\mathrm{sun}}$ and in massive star clusters. Heavy-seed scenarios predict $f_{\\mathrm{occ}}$ falling well below 1 for $M_*$ below $\\sim 10^9\\ M_{\\mathrm{sun}}$, while light-seed scenarios predict $f_{\\mathrm{occ}}$ near 1. The answer is $f_{\\mathrm{occ}}(M_*)$ with uncertainties from dynamical, accretion and tidal-disruption-event detections corrected for selection.","problem_ref":null,"references":"","settled_by":"Stellar-dynamical mass measurements or limits for a volume-limited sample of nearby dwarf galaxies (ELT-class adaptive optics), combined with X-ray AGN and tidal-disruption-event rates in dwarfs from wide-field surveys.","status_note":"A black hole of at least about $8200 M_{\\mathrm{sun}}$ was inferred in Omega Centauri from fast-moving stars (Haberle et al., Nature 631, 285, 2024, arXiv:2405.06015); the occupation fraction in dwarf galaxies is still unmeasured.","title":"What fraction of dwarf galaxies host intermediate-mass black holes?","topic_ref":"b31645054af13e29c5201707761f4cbb39ef8dced934561a5f80d1a755665bcf"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"93359ed11bea48f5e23edbadc439e38d363718a6cfc10288da66ab503f7a7b19","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"c7110fecccb4d28ad099a7fbac0d727b0d4f9703b05a5637dfd32b51e574e566","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"3L1WWH8tO7tonmmvy1cX6m2szAERoVpLnq085couUHNKR9rNpwU_BV-8vxNvhhkZkslh4QZV4zG7y2sKR13HCQ"},"schema":"pubphys.envelope/1"},"record_hash":"93359ed11bea48f5e23edbadc439e38d363718a6cfc10288da66ab503f7a7b19","leaf_index":529}