Distances and Evolutionary States of Supernova Remnant G18.9-1.1 and Candidate G28.6+0.0
Bibliographic record
Abstract
HI spectra of the supernova remnant G18.9-1.1 and the supernova remnant candidate G28.6+0.0 are analyzed. We compared the spectra to 13CO emission spectra and to spectra of HII regions in the area to determine kinematic distances. G18.9-1.1 is at 2.1 ± 0.4 kpc and G28.6+0.0 is at 9.0 ± 0.3 kpc from the Sun. Using the published X-ray spectra of G18.9-1.1, we apply supernova remnant models for shocked-ISM temperature and emission measure. We find that G18.9-1.1 has low, but not atypical, explosion energy of ≈3 × 1050 erg and is in a low-density region of the ISM, ~0.1 cm-3. It has age ~3700 yr if the ejecta mass is 1.4 Mʘ, typical of Type Ia SNe, or ~4700 yr if the ejecta mass is 5 Mʘ typical of core-collapse SN. The candidate G28.6+0.0 does not have reported X-ray emission, so we apply a basic Sedov model. The Sedov age is ~600 yr if the ISM density is 1 cm-3 but could be as old as ~6000 yr if the ISM density is as high as 100 cm-3.
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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".