REDSHIFT 6.4 HOST GALAXIES OF 10<sup>8</sup>SOLAR MASS BLACK HOLES: LOW STAR FORMATION RATE AND DYNAMICAL MASS
Bibliographic record
Abstract
We present Atacama Large Millimeter Array observations of rest-frame far-infrared continuum and [C ii ] line emission in two z = 6.4 quasars with black hole masses of ≈10 8 M ☉ . CFHQS J0210−0456 is detected in the continuum with a 1.2 mm flux of 120 ± 35 μJy, whereas CFHQS J2329−0301 is undetected at a similar noise level. J2329−0301 has a star formation rate limit of <40 M ☉ yr −1 , considerably below the typical value at all redshifts for this bolometric luminosity. Through comparison with hydro simulations, we speculate that this quasar is observed at a relatively rare phase where quasar feedback has effectively shut down star formation in the host galaxy. [C ii ] emission is also detected only in J0210−0456. The ratio of [C ii ] to far-infrared luminosity is similar to that of low-redshift galaxies of comparable luminosity, suggesting that the previous finding of an offset in the relationships between this ratio and far-infrared luminosity at low and high redshifts may be partially due to a selection effect due to the limited sensitivity of previous continuum data. The [C ii ] line of J0210−0456 is relatively narrow (FWHM = 189 ± 18 km s −1 ), indicating a dynamical mass substantially lower than expected from the local black hole–velocity dispersion correlation. The [C ii ] line is marginally resolved at 0 7 resolution with the blue and red wings spatially offset by 0 5 (3 kpc) and a smooth velocity gradient of 100 km s −1 across a scale of 6 kpc, possibly due to the rotation of a galaxy-wide disk. These observations are consistent with the idea that stellar mass growth lags black hole accretion for quasars at this epoch with respect to more recent times.
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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 | 0.001 | 0.001 |
| 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) | 0.010 | 0.002 |
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".