Astron. Astrophys. 354, 983-986 (2000)

3. X-ray emission from post-shock gas

The X-ray emission from the hot post-shock gas can be calculated using the expressions for the density and temperature given above. The X-ray luminosity due to emission by the post-shock gas in the direction of the movement of the shock can be expressed as

in ergs s^-1; n_e, n_i and T are dependent on x. Here n_i=n_He, where n_He is the density of helium nuclei (the main constituent of the wind from the Wolf-Rayet star) in the wind and n_e= 2n_i; A is the area of the shock and is 2r, where r_s is the radius of the shock and is 1.110¹¹ cm (Apparao 1997). The integrals are over the temperature range and the frequency band. Using the expressions for the density and temperature profiles in the post-shock gas given by Apparao (1997), we have evaluated the X-ray luminosity between 2 and 12 kev and find L_x 10³⁸ ergs s^-1 which is comparable to the observed value(White and Holt 1982; Willingale et al. 1985). Note that T_s given above corresponds to 4.7 keV, therefore the X-ray emission from the post-shock gas corresponds to the soft component.

© European Southern Observatory (ESO) 2000

Online publication: February 25, 2000
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