CARMA SURVEY TOWARD INFRARED-BRIGHT NEARBY GALAXIES (STING): MOLECULAR GAS STAR FORMATION LAW IN NGC 4254
Bibliographic record
Abstract
This study explores the effects of different assumptions and systematics on the determination of the local, spatially resolved star formation law. Using four star formation rate (SFR) tracers (Hñ with azimuthally averaged extinction correction, mid-infrared 24 üm, combined Hñ and mid-infrared 24 üm, and combined far-ultraviolet and mid-infrared 24 üm), several fitting procedures, and different sampling strategies, we probe the relation between SFR and molecular gas at various spatial resolutions (500 pc and larger) and surface densities ({ã_{H_2}}ââ°Ë 10-245 M sun pc-2) within the central ~6.5 kpc in the disk of NGC 4254. We explore the effect of diffuse emission using an unsharp masking technique with varying kernel size. The fraction of diffuse emission, f DE, thus determined is a strong inverse function of the size of the filtering kernel. We find that in the high surface brightness regions of NGC 4254 the form of the molecular gas star formation law is robustly determined and approximately linear (~0.8-1.1) and independent of the assumed fraction of diffuse emission and the SFR tracer employed. When the low surface brightness regions are included, the slope of the star formation law depends primarily on the assumed fraction of diffuse emission. In such a case, results range from linear when the fraction of diffuse emission in the SFR tracer is f DE <~ 30% (or when diffuse emission is removed in both the star formation and the molecular gas tracer) to super-linear (~1.4) when f DE >~ 50%. We find that the tightness of the correlation between gas and star formation varies with the choice of star formation tracer. The 24 üm SFR tracer by itself shows the tightest correlation with the molecular gas surface density, whereas the Hñ corrected for extinction using an azimuthally averaged correction shows the highest dispersion. We find that for R < 0.5R 25 the local star formation efficiency is constant and similar to that observed in other large spirals, with a molecular gas depletion time Ãâdep ~ 2 Gyr.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".