Bibliographic record
Abstract
It has been argued that certain broad absorption line quasars are viewed within 35 degrees of the axis of a relativistic radio jet, based on two-epoch radio flux density variability. It is true if the surface brightness of a radio source is observed to change by a sufficiently large amount, the inferred brightness temperature will exceed 10^12 K and Doppler beaming in our direction must be invoked to avoid a Compton cooling catastrophe. However, flux density changes cannot be linked to surface brightness changes without knowledge of the size of the source. If an optically thick source changes in projected area but not surface brightness, its brightness temperature is constant and its flux variability yields no constraint on its orientation. Moreover, as pointed out by Rees, spherical expansion of an emission source at relativistic speeds yields an apparently superluminal increase in its projected area, which can explain short-timescale flux density variability without requiring a relativistic jet oriented near to our line of sight. Therefore, two-epoch radio flux density variability by itself cannot unambiguously identify sources with jets directed towards us. Only VLBI imaging can robustly determine the fraction of broad absorption line quasars which are polar.
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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 | 0.004 | 0.009 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.001 | 0.006 |
| Scholarly communication | 0.004 | 0.011 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.004 | 0.003 |
| Insufficient payload (model declined to judge) | 0.012 | 0.003 |
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".