Radio, X-ray, and γ-ray emission models of the colliding-wind binary WR 140
Bibliographic record
Abstract
We use hydrodynamical models of the wind-collision region in the archetype colliding-wind system WR 140 to determine the spatial and spectral distributions of the radio, X-ray, and γ-ray emission from shock-accelerated electrons. Our calculations are for orbital phase 0.837 when the observed radio emission is close to maximum. Using the observed thermal X-ray emission at this phase in conjunction with the radio emission to constrain the mass-loss rates, we find that the O star mass-loss rate is consistent with the reduced estimates for O4-5 supergiants by Fullerton, Massa & Prinja, and the wind-momentum ratio, η= 0.02. This is independent of the opening angle deduced from radio very long baseline interferometry observations of the WCR that we demonstrate fail to constrain the opening angle. We show that the turnover at ∼3 GHz in the radio emission is due to free–free absorption, since models based on the Razin effect have an unacceptably large fraction of energy in non-thermal electrons. We find that the spectral index of the non-thermal electron energy distribution is flatter than the canonical value for diffusive shock acceleration, namely p < 2. Several mechanisms are discussed that could lead to such an index. Our inability to obtain fits to the radio data with p > 2 does not exclude the possibility of shock modification, but stronger evidence than that which currently exists is necessary for its support. Tighter constraints on p and the nature of the shocks in WR 140 will be obtained from future observations at MeV and GeV energies, for which we generally predict lower fluxes than those in previous works. Since the high stellar photon fluxes prevent the acceleration of electrons beyond γ≳ 105–106, TeV emission from colliding-wind binary systems will provide unambiguous evidence of pion-decay emission from accelerated ions. We finish by commenting on the emission and physics of the multiple wind collisions in dense stellar clusters, paying particular attention to the Galactic Centre.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".