Kinematics of the atomic ISM in M33 on 80 pc scales
Bibliographic record
Abstract
We present new L-band (1–2 GHz) observations of the nearby spiral galaxy M33 with 80 pc resolution obtained with the Karl G. Jansky Very Large Array. The H i observations, combined with H i measurements from the Green Bank Telescope, improve the spectral resolution and sensitivity (2.8 K rms noise in a 0.2 |${\rm km\, s^{-1}}$| channel) compared to previous observations. We find individual profiles are usually non-Gaussian, harbouring line wings, multiple components, and asymmetries. Given this spectral complexity, we quantify the motions in the atomic interstellar medium through moment analysis of the spectra and fits to aligned, stacked profiles. The measured value of the H i line width depends strongly on the method used, with the velocity stacked profiles aligned to the peak velocity giving the minimum value of σ = 7 |${\rm km\, s^{-1}}$| and all other methods giving higher values (σ ∼ 10 |${\rm km\, s^{-1}}$|). All measurements of the line width show a shallow radial trend, with σ decreasing by ∼2 |${\rm km\, s^{-1}}$| from Rgal = 0 to Rgal = 8 kpc. We consider a number of energy sources that might maintain the line width against turbulent dissipation, but no single source is adequate. We find excess emission relative to a Gaussian in the stacked profile line wings, ranging from 9 per cent to 26 per cent depending on how the spectra are aligned. By splitting the line wings into symmetric and asymmetric components, we find that the lagging rotational disc accounts for one-third of the line wing flux. We also find emission far from the rotation-axis of the galaxy in multiple discrete H i clouds, including a filament with a projected length of ∼8 kpc.
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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 | 0.000 |
| 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 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".