The X-ray Background from the Warm Gas of the Galactic Halo
The X-ray Background from the Warm Gas of the Galactic Halo作者机构：National Astronomical Observatories Chinese Academy of Sciences Beijing 100012
出 版 物：《Chinese Journal of Astronomy and Astrophysics》 (中国天文和天体物理学报（英文版）)
年 卷 期：2001年第1卷第5期
页 面：383-388页
核心收录：
学科分类：07[理学] 070401[理学-天体物理] 0704[理学-天文学]
基 金：the National Natural Science Foundation of China,under Grant No.19725311 the Ministry of Science and Technology of China,under Grant No.NKBRSF Gl9990754
主 题：cosmology: diffuse radiation Galaxy: formation Galaxy: halo X rays: galaxies
摘 要：Within the framework of the hierarchical scenario of galaxy formation, spiral galaxies like our own Galaxy are still growing at present. This opens a possibility that one might be able to see X-ray galactic halos from gravitationally heated gas with temperatures of 106 K as a result of bremsstrahlung. An interesting issue is whether the X-ray background produced by the warm gas in the halo of our Galaxy is detectable. We present a simple estimate of the strength and spectrum of the X-ray background from the Galactic halo and compare with the recent findings of a spatially variable soft X-ray component seen towards the north Galactic polar cap by Kuntz et al. (2001). It is shown that a good agreement, regardless of cosmological models, can be achieved if the gas fraction is as low as ~ 0.01. This requirement seems to be consistent with the extrapolated result from a number of independent observational and theoretical constraints established for groups and clusters of galaxies. In particular, the ex pected soft X-ray background from the warm gas of the Galactic halo is comparable to, or even exceeds that produced by the warm-hot gas in massive groups, and it may constitute the major source of contamination in the search for missing baryons through the detection of their soft X-ray emission, unless we can work out a way to properly remove the X-ray background (e.g., from anisotropy) from the halo of our Galaxy.
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