Hα‐derived Star Formation Rates for Three<i>z</i>≃0.75 EDisCS Galaxy Clusters
Bibliographic record
Abstract
We present Hα-derived SFRs for three z ≃ 0.75 galaxy clusters. Our 1 σ flux limit corresponds to a star formation rate (SFR) of 0.10-0.24 h M ☉ yr -1 , and our minimum reliable Hα + [N ] rest-frame equivalent width is 10 Å. We show that Hα narrowband imaging is an efficient method for measuring star formation in distant clusters. In two out of three clusters, we find that the fraction of star-forming galaxies increases with projected distance from the cluster center. We also find that the fraction of star-forming galaxies decreases with increasing local galaxy surface density in the same two clusters. We compare the median rate of star formation among star-forming cluster galaxies to a small sample of star-forming field galaxies from the literature and find that the median cluster SFRs are ~50% less than the median field SFR. We characterize cluster evolution in terms of the mass-normalized integrated cluster SFR and find that the z ≃ 0.75 clusters have more SFR per cluster mass on average than the z ≤ 0.4 clusters from the literature. The interpretation of this result is complicated by the dependence of the mass-normalized SFR on cluster mass and the lack of sufficient overlap in the mass ranges covered by the low- and high-redshift samples. We find that the fraction and luminosities of the brightest starburst galaxies at z ≃ 0.75 are consistent with their being progenitors of the poststarburst galaxies at z ≃ 0.45 if the poststarburst phase lasts several (~5) times longer than the starburst phase.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".