Gravitational Redshift for Rapidly Rotating Neutron Stars
Bibliographic record
Abstract
Abstract The oblate Schwarzschild (OS) approximation is a method often used to compute the flux of X-rays emitted from a rapidly rotating neutron star. In this approximation, the oblate shape of the rotating star is embedded in the Schwarzschild metric, which is used to compute the redshift of photon energies as they propagate from the star to the telescope. In this paper, we demonstrate that there are small errors introduced by the standard treatment of photon redshift in the OS approximation and provide a simple method to correct these errors. These errors are constant in phase, so this results in a constant absolute reduction in the flux. For PSR J0740+6620, the most rapidly spinning of the pulsars observed by the Neutron star Interior Composition Explorer (NICER), we estimate the flux errors are less than 1%, which is an order of magnitude smaller than the uncertainty in the distance, so this does not affect the mass and radius constraints found for this pulsar. The errors for the other pulsars observed by NICER are even smaller. However, this correction should be included when analyzing data for more rapidly rotating X-ray pulsars with spin frequencies near 600 Hz.
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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 | 0.001 | 0.004 |
| 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 | 0.001 |
| 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".