[C i](1–0) and [C i](2–1) in Resolved Local Galaxies*
Bibliographic record
Abstract
Abstract We present resolved [C i] line intensities of 18 nearby galaxies observed with the SPIRE FTS spectrometer on the Herschel Space Observatory. We use these data along with resolved CO line intensities from J up = 1 to 7 to interpret what phase of the interstellar medium the [C i] lines trace within typical local galaxies. A tight, linear relation is found between the intensities of the CO(4–3) and [C i](2–1) lines; we hypothesize this is due to the similar upper level temperature of these two lines. We modeled the [C i] and CO line emission using large-velocity gradient models combined with an empirical template. According to this modeling, the [C i](1–0) line is clearly dominated by the low-excitation component. We determine [C i] to molecular mass conversion factors for both the [C i](1–0) and [C i](2–1) lines, with mean values of α [C i](1−0) = 7.3 M ⊙ K−1 km−1 s pc−2 and α [C i](2−1) = 34 M ⊙ K−1 km−1 s pc−2 with logarithmic root-mean-square spreads of 0.20 and 0.32 dex, respectively. The similar spread of to (derived using the CO(2–1) line) suggests that [C i](1–0) may be just as good a tracer of cold molecular gas as CO(2–1) in galaxies of this type. On the other hand, the wider spread of α [C i](2−1) and the tight relation found between [C i](2–1) and CO(4–3) suggest that much of the [C i](2–1) emission may originate in warmer molecular gas.
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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 | 0.001 |
| Scholarly communication | 0.001 | 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".