Monday, January 16, 2012

1201.2879 (J. A. Toalá et al.)

X-ray emission from the Wolf-Rayet bubble S308    [PDF]

J. A. Toalá, M. A. Guerrero, Y. -H. Chu, R. A. Gruendl, S. J. Arthur, R. C. Smith, S. L. Snowden
The Wolf-Rayet (WR) bubble S\,308 around the WR star HD\,50896 is one of the only two WR bubbles known to possess X-ray emission. We present \textit{XMM-Newton} observations of three fields of this WR bubble that, in conjunction with an existing observation of its Northwest quadrant, map most of the nebula. The X-ray emission from S\,308 displays a limb-brightened morphology, with a 22\arcmin\ in size central cavity and a shell thickness of $\sim$8\arcmin. This X-ray shell is confined by the optical shell of ionized material. The spectrum is dominated by the He-like triplets of \ion{N}{6} at $\sim$0.43 keV and \ion{O}{7} at $\sim$0.5 keV, and declines towards high energies, with a faint tail up to 1 keV. This spectrum can be described by a two-temperature optically thin plasma emission model ($T_1\sim1.1\times10^6$ K, $T_2\sim13\times10^6$ K), with a total X-ray luminosity $\sim3\times10^{33}$ erg s$^{-1}$ at the assumed distance of 1.8 kpc. Qualitative comparison of the X-ray morphology of S\,308 with the results of numerical simulations of wind-blown WR bubbles suggests a progenitor mass of $40\,M_\odot$ and an age in the WR phase $\sim$20,000 yrs. The X-ray luminosity
View original: http://arxiv.org/abs/1201.2879

No comments:

Post a Comment