Chandra Detects Low-luminosity Active Galactic Nucleus with <i>M</i> <sub>BH</sub> = 10<sup>4</sup>–10<sup>6</sup> <i> M</i> <sub>⊙</sub> in Nearby (<i>z</i> < 0.5) Dwarf and Star-forming Galaxies
Bibliographic record
Abstract
Abstract We searched the Chandra and XMM archives for 900 Green Pea galaxies to identify signs of active galactic nuclei (AGN). Green peas are low-mass, emission-line galaxies that resemble high-redshift dwarf galaxies. From 29 observations, we detected X-rays in nine galaxies with signal-to-noise ratio > 3. These X-ray sources also show He ii and broad Hα emissions, suggesting winds, though the weak correlation between their line widths implies that the He ii emission is not from super-Eddington accretors. The ratio of X-ray luminosity to star formation rate aligns with an anticorrelation with metallicity for most detected sources, pointing to ultraluminous X-ray sources as likely contributors. The X-ray emission exceeds what stellar processes can produce, supporting the existence of low-luminosity AGN. Using the broad Hα emission lines, we infer black hole masses ranging from 104 to 106 M ⊙ in these sources. Since Green Peas are significant Lyman continuum leakers, these AGN may have played a role in cosmic reionization.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".