The geometry of the Hercules X-1 accretion disk from X-rays
Bibliographic record
Abstract
Hercules X-1 has a consistent 35-day periodic light-curve in X-rays consisting of main high, short high and low states caused by a precessing tilted and twisted accretion disk. The MAXI instrument has recently measured the average 35-day X-ray light-curve with small errors. The current work utilizes the MAXI data and ray-tracing software to derive a better-constrained geometric model of the accretion disk than previous studies. A basic 3-D model based on previous work is iteratively expanded in complexity until it can satisfactorily replicate the 35-day light-curve. We summarize the disk models tested and confirm the requirement for a scattering corona and for a disk atmosphere which is different for the inner and outer disk. We are able to constrain the system inclination to $$85.5\pm 0.3^{\circ }$$ , much improved compared to previous estimates ( $$\sim$$ 82 to $$88^\circ$$ ). The constraint on inclination allows for more accurate determinations of the radius of the companion HZ Her (2.64 to 2.83 $$\times 10^{11}$$ cm), mass of the HZ Her (2.34 to 2.45 $$\hbox {M}_\odot$$ ) and mass of the neutron star (1.52 to 1.69 $$\hbox {M}_\odot$$ ).
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".