ON THE EVOLUTION OF THE MOLECULAR GAS FRACTION OF STAR-FORMING GALAXIES
Bibliographic record
Abstract
We present IRAM Plateau de Bure interferometric detections of CO ( J = 1 → 0) emission from a 24 μm-selected sample of star-forming galaxies at z = 0.4. The galaxies have polycyclic aromatic hydrocarbon 7.7 μm-derived star formation rates of SFR ∼30–60 M ☉ yr −1 and stellar masses M ⋆ ∼ 10 11 M ☉ . The CO ( J = 1 → 0) luminosities of the galaxies imply that the disks still contain a large reservoir of molecular gas, contributing ∼20% of the baryonic mass, but have star formation "efficiencies" similar to local quiescent disks and gas-dominated disks at z ∼ 1.5–2. We reveal evidence that the average molecular gas fraction has undergone strong evolution since z ∼ 2, with f gas ∝ (1 + z ) ∼2±0.5 . The evolution of f gas encodes fundamental information about the relative depletion/replenishment of molecular fuel in galaxies and is expected to be a strong function of halo mass. We show that the latest predictions for the evolution of the molecular gas fraction in semi-analytic models of galaxy formation within a ΛCDM universe are supported by these new observations.
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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 | 0.001 |
| 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) | 0.001 | 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".