The Expansion of G11.2-0.3, a Radio Composite Supernova Remnant
Bibliographic record
Abstract
We compare recent observations of the supernova remnant G11.2-0.3 taken with the Very Large Array (VLA) during 2001-2002 with images from VLA archives (1984-1985) to detect and measure the amount of expansion that has occurred during 17 years. The bright, circular outer shell shows a mean expansion of 0.71% ± 0.15% and 0.50% ± 0.17%, from 20 and 6 cm data, respectively, which corresponds to a rate of 0 057 ± 0 012 yr -1 at 20 cm and 0 040 ± 0 013 yr -1 at 6 cm. From this result, we estimate the age of the remnant to be roughly between 960 and 3400 yr old, according to theoretical models of supernova evolution. This is highly inconsistent with the 24,000 yr characteristic age of PSR J1811-1925, located at the remnant's center, but rather is consistent with the time that has passed since the observation of the historical supernova of A.D. 386. We also predict that G11.2-0.3 is currently in a pre-Sedov evolutionary state and set constraints on the distance to the remnant based on Chandra X-ray spectral results.
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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 | 0.000 |
| 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 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".