The Properties of the Galactic Hot Gaseous Halo from X-Ray Emission

The extended hot X-ray emitting gaseous halo of the Milky Way has an optical depth similar to 1 for the dominant emission lines of O VII and O VIII, which are used to infer the halo properties. To improve on halo gas properties, we treat optical depth effects with a Monte Carlo radiative transfer model, which leads to slightly steeper density profiles (beta approximate to 0.5) than if optical depths effects were ignored. For the preferred model where the halo is rotating on cylinders at 180 km s(-1), independent fits to both lines lead to identical results, where the core radius is 2.5 kpc and the turbulent component of the Doppler-b parameter is 100-120 km s(-1); the turbulent pressure is 20% of the thermal pressure. The fit is improved when emission from a disk is included, with a radial scale length of 3 kpc (assumed) and a fitted vertical scale height of approximately 1.3 kpc. The disk component is a minor mass constituent and has low optical depth, except at low latitudes. The gaseous mass is 3-4 x 1010 M-circle dot within 250 kpc, similar to our previous determinations and significantly lower than the mass of the missing baryons, which is 1.7 x 10(11) M-circle dot.