| Expectation for the X—ray Galactic Halo |
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| 引用本文： | Zhi－YingHuo.Expectation for the X—ray Galactic Halo[J].中国天文和天体物理学报,2002,2(2):112-116. |
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| 作者姓名： | Zhi－YingHuo |
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| 作者单位： | Zhi-Ying Huo National Astronomical Observatories，Chinese Academy of Sciences，Beijing 100012 Department of Physics，Tianjin Normal University，Tianjin 300073 |
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| 摘 要： | 1 INTRODUCTION In the hierarchical clustering model, massive objects form by gravitational aggregation oflower-mass objects, and the disks in spiral galaxies like our Galaxy form by a late accretionof gas from an extended reservoir around the galactic halos. According to this scenario, spiralgalaxies are still growing at present. At the virial temperature of galactic halos, T r.-' io5 ?i06 K, the dominant cooling mech-anism is X-ray bremsstrahlung. If the cooling rate is significant, the…
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| 关 键 词： | 宇宙论 散射 辐射 银河系 X射线 形态 |
Expectation for the X-ray Galactic Halo |
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| Zhi-Ying Huo.Expectation for the X-ray Galactic Halo[J].Chinese Journal of Astronomy and Astrophysics,2002,2(2):112-116. |
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| Authors: | Zhi-Ying Huo |
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| Institution: | NationalAstronomicalObservatories,ChineseAcademyofSciences,Beijing100012 |
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| Abstract: | We present an estimate of the strength and spectrum of the X-ray background from the warm gas associated with the galactic halo. This investigation is motivated primarily by the recent detection of a spatially variable soft X-ray component towards the north Galactic plar cap by Kuntz et al.(2001), suggesting that the warm gas heated by gravitational shocks of the Galactic halo may produce a significant contribution to the soft X-ray sky. Another purpose of the study is to refine the recent theoretical prediction of the X-ray spectrum from the Galactic halo by Xue (2001) who adopted an ideal and simple isothermal model for the gas and dark matter distributions of the Galactic halo.We use the universal density profile for the dark matter distributions of the Galactic halo to evaluate the X-ray properties of the warm gas either in hydrostatic equilibrium with, or tracing the underlying gravitational potential of the Galaxy. It has been shown that our prediction is consistent with the measured soft X-ray component towards the north Galactic polar cap if the gas fraction is taken to be -0.005. |
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| Keywords: | cosmology: diffuse radiation -Galaxy: formation - X-rays: galaxies |
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