Far-Infrared Detection of H <sub>2</sub> D <sup>+</sup> toward Sgr B2
Bibliographic record
Abstract
We report on the first far-IR detection of H 2 D + , using the Infrared Space Observatory , in the line of sight toward Sgr B2 in the Galactic center. The transition at λ = 126.853 μm connecting the ground level of o-H 2 D + , 1 1, 1 , with the 2 1, 2 level at 113 K is observed in absorption against the continuum emission of the cold dust of the source. The line is broad, with a total absorption covering 350 km s -1 , i.e., similar to that observed in the fundamental transitions of H 2 O, OH, and CH at ~179, 119, and 149 μm, respectively. For the physical conditions of the different absorbing clouds, the H 2 D + column density ranges from 2 to 5 × 10 13 cm -2 , i.e., near an order of magnitude below the upper limits obtained from ground-based submillimeter telescopes. The derived H 2 D + abundance is of a few times 10 -10 , which agrees with chemical model predictions for a gas at a kinetic temperature of ≃20 K.
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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 | 0.000 | 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) | 0.003 | 0.001 |
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".