论文标题
附近的Seyfert 2 Galaxy NGC 7479的多个上述X射线研究：将色谱柱密度变化与圆环几何形状链接
A multi-epoch X-ray study of the nearby Seyfert 2 galaxy NGC 7479: Linking column density variability to the torus geometry
论文作者
论文摘要
活跃的银河核（AGN）是通过积聚超质量黑洞的动力，周围是遮盖物质的圆环。最近的研究表明，以前被认为是均匀的圆环结构似乎是“斑点”的：视线线氢柱密度的可变性检测，实际上与具有不同柱密度的云制成的复杂结构的遮盖物的描述相匹配。在这项工作中，我们对Seyfert 2 Galaxy NGC 7479的X射线光谱进行了多上述分析，以估计其圆环特性，例如平均柱密度和覆盖因子。圆环的视线氢柱密度变化的测量使我们能够在距中央发动机的云距离上获得上限。另外，使用源的X射线光度，我们估计Eddington的比率在所有时期的EDD = 0.04-0.05范围内。
Active galactic nuclei (AGN) are powered by accreting supermassive black holes, surrounded by a torus of obscuring material. Recent studies have shown how the torus structure, formerly thought to be homogeneous, appears to be 'patchy': the detection of variability in the line-of-sight hydrogen column density, in fact, matches the description of an obscurer with a complex structure made of clouds with different column density. In this work, we perform a multi-epoch analysis of the X-ray spectra of the Seyfert 2 galaxy NGC 7479 in order to estimate its torus properties, such as the average column density and the covering factor. The measurement of the line-of-sight hydrogen column density variability of the torus allows us to obtain an upper limit on the cloud distance from the central engine. In addition, using the X-ray luminosity of the source, we estimate the Eddington ratio to be in a range of Edd=0.04-0.05 over all epochs.
