XMM-Newton X-ray Observations of the Wolf-Rayet Binary System WR 147
| Autor: | Skinner, S. L., Zhekov, S. A., Guedel, M., Schmutz, W. |
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| Rok vydání: | 2007 |
| Předmět: | |
| Zdroj: | Mon.Not.Roy.Astron.Soc.378:1491-1498,2007 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1111/j.1365-2966.2007.11892.x |
| Popis: | We present results of a 20 ksec X-ray observation of the Wolf-Rayet (WR) binary system WR 147 obtained with XMM-Newton. Previous studies have shown that this system consists of a nitrogen-type WN8 star plus an OB companion whose winds are interacting to produce a colliding wind shock. X-ray spectra from the pn and MOS detectors confirm the high extinction reported from IR studies and reveal hot plasma including the first detection of the Fe K-alpha line complex at 6.67 keV. Spectral fits with a constant-temperature plane-parallel shock model give a shock temperature kT(shock) = 2.7 keV [T(shock) ~ 31 MK], close to but slightly hotter than the maximum temperature predicted for a colliding wind shock. Optically thin plasma models suggest even higher temperatures, which are not yet ruled out. The X-ray spectra are harder than can be accounted for using 2D numerical colliding wind shock models based on nominal mass-loss parameters. Possible explanations include: (i) underestimates of the terminal wind speeds or wind abundances, (ii) overly simplistic colliding wind models, or (iii) the presence of other X-ray emission mechanisms besides colliding wind shocks. Further improvement of the numerical models to include potentially important physics such as non-equilibrium ionization will be needed to rigorously test the colliding wind interpretation. Comment: 8 pages, 7 figures |
| Databáze: | arXiv |
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