NEAR-INFRARED [Fe II] AND H<sub>2</sub>LINE OBSERVATIONS OF THE SUPERNOVA REMNANT 3C 396: PROBING THE PRESUPERNOVA CIRCUMSTELLAR MATERIALS
Bibliographic record
Abstract
We present the results of near-infrared [Fe ii ] and H 2 line imaging and spectroscopic observations of the supernova remnant 3C 396 using the Palomar 5 m Hale telescope. We detect long, filamentary [Fe ii ] emission delineating the inner edge of the radio emission in the western boundary of the remnant in imaging observations, together with a bright [Fe ii ] emission clump close to the remnant center. There appears to be faint, diffuse [Fe ii ] emission between the central clump and the western filamentary emission. The spectroscopic observations determine the expansion velocity of the central clump to be ∼56 km s −1 . This is far smaller than the expansion velocity of 3C 396 obtained from X-ray observations, implying the inhomogeneity of the ambient medium. The electron number density of the [Fe ii ] emission gas is ⩽ 2000 cm −3 . The H 2 line emission, on the other hand, lies slightly outside the filamentary [Fe ii ] emission in the western boundary, and forms a rather straight filament. We suggest that the [Fe ii ] emission represents dense clumps in the wind material from the red supergiant phase of a Type IIL/b progenitor of 3C 396, which have been swept up by the supernova remnant shocks. The H 2 emission may represent either the boundary of a wind bubble produced during the main-sequence phase of the progenitor or molecular clumps left over inside the bubble. We propose that the near-infrared [Fe ii ] and H 2 emission observed in several supernova remnants of Type IIL/b SNe likely have the same origin.
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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 | 0.001 | 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".