<i>FUSE</i>Measurements of Far‐Ultraviolet Extinction. II. Magellanic Cloud Sight Lines
Bibliographic record
Abstract
We present an extinction analysis of nine reddened/comparison star pairs in the Large and Small Magellanic Clouds (LMC and SMC) based on Far-Ultraviolet Spectroscopic Explorer ( FUSE ) FUV observations. To date, just two LMC sight lines have probed dust grain composition and size distributions in the Magellanic Clouds using spectral data for wavelengths as short as 950 Å. We supplement these two with data from four regions distinguished by their IR through UV extinction curves and grouped as LMCAvg, LMC2, SMC bar, and SMC wing. Despite the distinct characters of extinction in the Clouds and Milky Way, our results are generally analogous to those found for Galactic curves—namely, that the FUSE portions of each extinction curve are described reasonably well by Fitzpatrick & Massa curves fitted only to longer wavelength data and lack any dramatic new extinction features, and any deviations from the Cardelli, Clayton, & Mathis (CCM) formalism continue into FUV wavelengths. A maximum entropy method analysis of all of these curves suggests that LMCAvg and SMC wing sight lines, whose extinction parameters more closely resemble those for Galactic paths, require more silicon and/or carbon in dust than current abundance measurements would indicate are available. The requirements for LMC2 and SMC bar sight lines do not fully tax the available reservoirs, in part because large grains contribute less to the extinction in these directions. An intermediate product of this extinction analysis is the measurement of new H 2 abundances in the Magellanic Clouds. Collectively considering Cloud sight lines that possess significant H 2 column densities, E ( B - V )/ N (H ) ratios are reduced by significant factors relative to the Galactic mean, whereas the corresponding E ( B - V )/ N (H 2 ) values more closely resemble their Galactic counterpart. These trends reflect the fact that among these sight lines f (H 2 ) values are lower than those common in the Milky Way for paths with similar degrees of reddening.
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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 | 0.002 | 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".