Probing interstellar turbulence in cirrus with deep optical imaging: no sign of energy dissipation at 0.01 pc scale
Bibliographic record
Abstract
Diffuse Galactic light has been observed in the optical since the 1930s. We propose that, when observed in the optical with deep imaging surveys, it can be used as a tracer of the turbulent cascade in the diffuse interstellar medium (ISM), down to scales of about 1 arcsec. Here we present a power spectrum analysis of the dust column density of a diffuse cirrus at high Galactic latitude (l ≈ 198°, b ≈ 32°) as derived from the combination of a MegaCam g-band image, obtained as part of the MATLAS large programme at the CFHT, with Planck radiance and WISE 12 μm data. The combination of these three datasets have allowed us to compute the density power spectrum of the H <ns0:sc>i</ns0:sc> over scales of more than three orders of magnitude. We found that the density field is well described by a single power law over scales ranging from 0.01 to 50 pc. The exponent of the power spectrum, γ = −2.9 ± 0.1, is compatible with what is expected for thermally bi-stable and turbulent H <ns0:sc>i</ns0:sc>. We did not find any steepening of the power spectrum at small scales indicating that the typical scale at which turbulent energy is dissipated in this medium is smaller than 0.01 pc. The ambipolar diffusion scenario that is usually proposed as the main dissipative agent, is consistent with our data only if the density of the cloud observed is higher than the typical values assumed for the cold neutral medium gas. We discuss the new avenue offered by deep optical imaging surveys for the study of the low density ISM structure and turbulence.
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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".