标题： 银河棒状X射线辐射的起源 显示英文标题

标题： Origin of the Galactic ridge X-ray emission

摘要： 我们分析了基于 RXTE/PCA 扫描和扫视观测构建的银河系脊线 X 射线发射（GRXE）的地图，该地图是在 3-20 keV 能量范围内生成的。 我们表明，GRXE 的强度与银河系近红外表面亮度密切相关，因此追踪了银河系恒星质量分布。 GRXE 包含两个空间成分，可以识别为银河系的核球/棒状结构和盘状结构。 从 X 射线数据确定的这些成分参数与从近红外数据推导出的参数一致。 推断的 3-20 keV X 射线与近红外表面亮度之比 I(3-20 keV) (1e-11 erg/s/cm²/deg²)/I_(3.5μm)(MJy/sr) = 0.26±0.05，以及 X 射线与近红外亮度之比 L_(3-20 keV)/L_(3-4 μm) = (4.1±0.3)e-5。 对应的 3-20 keV 亮度与恒星质量之比为 L_x/M_Sun = (3.5\pm 0.5) 10^{27}erg/s，这在不确定性范围内与邻近太阳区域点源 X 射线源的单位恒星质量累积发射率一致（见 Sazonov 等人的一篇相关论文）。 这表明 GRXE 的主体是由弱 X 射线源组成的，主要是激变变星和具有活跃日冕的双星系统。 从太阳邻域数据确定的这些源类别的相对贡献也可以解释 GRXE 的能量谱。 根据本地 X 射线源的亮度函数，我们预测为了在未来观测中将 90% 的 GRXE 分辨为离散源，需要达到约 10^{-16}erg/s/cm² (2–10 keV) 的灵敏度极限。 显示英文摘要

摘要： We analyze a map of the Galactic ridge X-ray emission (GRXE) constructed in the 3-20 keV energy band from RXTE/PCA scan and slew observations. We show that the GRXE intensity closely follows the Galactic near-infrared surface brightness and thus traces the Galactic stellar mass distribution. The GRXE consists of two spatial components which can be identified with the bulge/bar and the disk of the Galaxy. The parameters of these components determined from X-ray data are compatible with those derived from near-infrared data. The inferred ratio of X-ray to near-infrared surface brightness I(3-20 keV) (1e-11 erg/s/cm2/deg2)/I_(3.5micron)(MJy/sr)=0.26+/-0.05, and the ratio of X-ray to near-infrared luminosity L_(3-20 keV)/L_(3-4 micron)=(4.1+/-0.3)e-5. The corresponding ratio of the 3-20 keV luminosity to the stellar mass is L_x/M_Sun= (3.5\pm0.5) 10^{27} erg/s, which agrees within the uncertainties with the cumulative emissivity per unit stellar mass of point X-ray sources in the Solar neighborhood, determined in an accompanying paper (Sazonov et al.). This suggests that the bulk of the GRXE is composed of weak X-ray sources, mostly cataclysmic variables and coronally active binaries. The fractional contributions of these classes of sources to the total X-ray emissivity determined from the Solar neighborhood data can also explain the GRXE energy spectrum. Based on the luminosity function of local X-ray sources we predict that in order to resolve 90% of the GRXE into discrete sources a sensitivity limit of ~10^{-16} erg/s/cm2 (2--10 keV) will need to be reached in future observations.