Australia Telescope Compact Array Radio Imaging of the Proplyd‐like Objects in the Giant H<scp>ii</scp>Region NGC 3603
Bibliographic record
Abstract
Three cometary-shaped objects in the giant H II region NGC 3603, originally found and identified as proto-planetary disks (proplyds) by Brandner and coworkers using the Hubble Space Telescope and the Very Large Telescope in the optical and near-infrared, have been detected with the Australia Telescope Compact Array in the radio continuum at 3 and 6 cm. All three proplyd-like objects are clearly resolved with an extent of a few arcseconds. The integrated 6 cm fluxes are up to 1.3 times higher than the 3 cm fluxes with spectral indices averaged over the whole clump between α = -0.1 and -0.5 ( S ν ∝ ν α ), indicating the likely presence of nonthermal emission in at least some of the sources. We present spectral-index maps and show that the sites of negative radio spectral indices are predominantly concentrated in the direction of the tails in at least two of the three proplyd-like nebulae, while positive spectral indices are found in the region facing the ionizing star cluster. We propose that thermal bremsstrahlung and nonthermal synchrotron radiation are at work in all three proplyd-like sources. In at least one of the three objects, optically thin nonthermal synchrotron emission appears to dominate when averaged over its whole spatial extent, while the spectrum of a second source shows a marginal indication of a nonthermal spectrum. The average spectrum of the third source is in agreement with thermal bremsstrahlung. All measured fluxes are at least one order of magnitude higher than those predicted by Brandner and coworkers. Upper limits for mass-loss rates due to photoevaporation are calculated to be ~10 -5 M ☉ yr -1 and for electron densities to be ~10 4 cm -3 . Due to the unexpectedly large radio luminosities of the proplyd-like features and because the radio emission is extended, a (proto-) stellar origin of the nonthermal emission from a dust enshrouded star appears unlikely. Instead, we propose that magnetized regions within the envelope of the proplyd-like nebulae exist.
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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 | 0.001 | 0.001 |
| 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) | 0.001 | 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".