The far-infrared/radio correlation and radio spectral index of galaxies in the SFR–<i>M</i><sub>∗</sub>plane up to<i>z</i>~2
Bibliographic record
Abstract
We study the evolution of the radio spectral index and far-infrared/radio correlation (FRC) across the star-formation rate -stellar masse (i.e. SFR-M * ) plane up to z 2. We start from a stellar-mass-selected sample of galaxies with reliable SFR and redshift estimates. We then grid the SFR-M * plane in several redshift ranges and measure the infrared luminosity, radio luminosity, radio spectral index, and ultimately the FRC index (i.e. q FIR ) of each SFR-M *z bin. The infrared luminosities of our SFR-M *z bins are estimated using their stacked far-infrared flux densities inferred from observations obtained with the Herschel Space Observatory. Their radio luminosities and radio spectral indices (i.e. , where S - ) are estimated using their stacked 1.4 GHz and 610 MHz flux densities from the Very Large Array and Giant Metre-wave Radio Telescope, respectively. Our far-infrared and radio observations include the most widely studied blank extragalactic fields -GOODS-N, GOODS-S, ECDFS, and COSMOS -covering a total sky area of 2.0 deg 2 . Using this methodology, we constrain the radio spectral index and FRC index of star-forming galaxies with M * > 10 10 M and 0 < z < 2.3. We find that 1.4 GHz 610 MHz does not evolve significantly with redshift or with the distance of a galaxy with respect to the main sequence (MS) of the SFR-M * plane (i.e. log(SSFR) MS = log[SSFR(galaxy)/SSFR MS (M * , z)]). Instead, star-forming galaxies have a radio spectral index consistent with a canonical value of 0.8, which suggests that their radio spectra are dominated by non-thermal optically thin synchrotron emission. We find that the FRC index, q FIR , displays a moderate but statistically significant redshift evolution as q FIR (z) = (2.350.08)(1+z) - 0.12 0.04 , consistent with some previous literature. Finally, we find no significant correlation between q FIR and log(SSFR) MS , though a weak positive trend, as observed in one of our redshift bins (i.e. [q FIR ]/[log(SSFR) MS ] = 0.22 0.07 at 0.5 < z < 0.8), cannot be firmly ruled out using our dataset.
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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 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".