The Faintness of the 158 Micron [C <scp>ii</scp> ] Transition in the <i>z</i> =6.42 Quasar SDSS J1148+5251
Bibliographic record
Abstract
We report the nondetection of the [C II] ( 2 P 3/2 → 2 P 1/2 ) 157.74 μm transition in the z = 6.42 quasar SDSS J1148+5251 after 37.5 hr of integration with the James Clerk Maxwell Telescope. This transition is the main cooling line of the star-forming interstellar medium and usually the brightest far-infrared (FIR) line in galaxies. Our observed 1 σ rms = 1.3 mK in the T scale translates to L < 2.6 × 10 9 L ☉ . Using a recent estimate of the FIR continuum of this quasar, we derive for SDSS J1148+5251 L / L FIR < 5 × 10 -4 , a ratio similar to that observed in local ultraluminous infrared galaxies but considerably smaller than what is typical in nearby normal and starburst galaxies. This indicates that the small L / L FIR ratio observed locally in luminous FIR objects also persists at the highest redshifts.
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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 | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.009 | 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".