Atomic Alignment and Diagnostics of Magnetic Fields in Diffuse Media
Bibliographic record
Abstract
We continue our studies of alignment of atoms by radiation in diffuse media and their realignment by the ambient magnetic field. We understand atomic alignment as the alignment of atoms or ions in their ground or metastable states that have more than two fine or hyperfine sublevels. In particular, we consider the alignment in interstellar and circumstellar media, with the goal of developing new diagnostics of magnetic fields in these environments. We provide predictions of the polarization that arises from astrophysically important aligned atoms (ions) with fine structure of the ground level, namely, O I, S II, and Ti II. Unlike our earlier papers which dealt with weak fields only, a part of our current paper is devoted to the studies of atomic alignment when magnetic fields get strong enough to affect the emission from the excited level. This is a regime of the Hanle effect, but modified by the atomic alignment of the atomic ground state. We also discuss the ground Hanle effect where the magnetic splitting is comparable to the pumping rate. Using an example of emission and absorption lines of the S II ion we demonstrate how polarimetric studies can probe magnetic fields in circumstellar regions and accretion disks. In addition, we show that atomic alignment induced by anisotropic radiation can induce substantial variations of magnetic dipole transitions within the ground state, thus affecting abundance studies based on this emission. Moreover, we show that the radio emission arising this way is polarized, which provides a new way to study magnetic fields, e.g., at the epoch of universe reionization.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".