Abstract
The diffuse soft X-ray background in 0.07∼ 2.0 keV has been observed along a small circle with the angular width of 10– covering b=—57– ∼ 77– and crossing the galactic plane at l=125– and 283–. Observed spectra are well fitted with models emitted from a thin hot gas with two or multi-temperature components and attenuated by a slab or interspersed neutral gas clouds. However the multi-temperature component model has some difficulties to explain the diffuse component expected from observations of OVI absorption lines. The two temperature component model with interspersed clouds consistently interprets a physical state of the hot interstellar medium. It turned out that the hot interstellar medium interspersed with neutral clouds of a representative hydrogen column density of 1× 1020 cm-2has two temperature components (105.8 K,(1.2-4.5)× 106 K) and a disk-like distribution with the thickness of 580(± 100). {(p/k)/104cm-3 K} -2 pc at the pressure of p/k cm-3 K along the galactic plane. Its pressure (p/k) is obtained to be 1.4(+0.7,-0.5)× 104cm-3 K, assuming that hot gases responsible for the diffuse soft X-rays and OVI ions are in pressure equilibrium. This interpretation qualitatively agrees with the theoretical prediction proposed by McKee and Ostriker.
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Sato, Y., Tsunemi, H. & Yamashita, K. An Observation of Diffuse Soft X-Ray Background and Distribution of Hot Interstellar Medium. Astrophysics and Space Science 250, 53–73 (1997). https://doi.org/10.1023/A:1000413807683
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DOI: https://doi.org/10.1023/A:1000413807683