Extreme properties of a compact and massive accreting black hole host in the first 500 Myr
Bibliographic record
Abstract
Little red dots (LRDs) are a high redshift galaxy population. Despite their high number densities, their nature is still uncertain. Here we present CANUCS-LRD-z8.6, a spectroscopically confirmed little red dot at a spectroscopic redshift of zspec = 8.6319, hosting an active galactic nucleus. Its spectrum exhibits broad Hβλ4863 Å emission, high-ionization lines (C iv, N iv]), high electron temperature, which are indicative of active galactic nucleus activity, and low metallicity (Z < 0.1−0.2Z⊙). The inferred black hole mass, $${M}_{{{{\rm{BH}}}}}=1.{0}_{-0.4}^{+0.6}\times 1{0}^{8}\,{{{{\rm{M}}}}}_{\odot }$$ , poses strong constraints on current black hole formation models and simulations. Additionally, its black hole is over-massive relative to its host, deviating from local MBH − M* relations, suggesting an early, rapid black hole growth preceding that of its galaxy. CANUCS-LRD-z8.6 may represent an evolutionary link between early massive black holes and the luminous quasars observed at z = 6. Little Red Dots (LRDs) are a high-redshift galaxy population with unclear nature. Here, authors show CANUCS-LRD-z8.6, a spectroscopically confirmed LRD, hosting an active galactic nucleus, and its properties provide insights for early black hole and galaxy formation.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".