标题： 塞弗特1型星系NGC 5548中的质量外流 显示英文标题

标题： Mass Outflow in the Seyfert 1 Galaxy NGC 5548

摘要： 我们研究了塞弗特1型星系NGC 5548历史上处于低态时的紫外线吸收和发射线，该光谱于2004年2月使用哈勃空间望远镜上的太空望远镜成像光谱仪（STIS）以高空间和光谱分辨率获得。我们分离出一个宽度为680公里/秒（FWHM）的发射成分，它来自“中间线区域”（ILR），与我们在距离中心连续光源约1秒差距处发现的NGC 4151中的类似。通过对NGC 5548中的五个固有吸收成分及其在8年时间跨度内的行为进行详细分析，我们提供了证据表明大多数紫外线吸收体仅部分覆盖ILR，并且不覆盖扩展的紫外线连续辐射区域，最有可能来自核区周围的热星。我们还发现四个紫外线吸收体距离ILR更远（>70秒差距），并且没有足够的N V或C IV列密度成为吸收状态下的ILR。至少部分紫外线吸收组分3，在径向速度为-530公里/秒时，很可能负责大部分距离中心源<7秒差距的X射线吸收。我们在NGC 4151中看到ILR的吸收而在NGC 5548中未见这一事实表明ILR相对于狭窄线区域外流轴位于相对较大的极角（~45度）。 显示英文摘要

摘要： We present a study of the intrinsic UV absorption and emission lines in an historically low-state spectrum of the Seyfert 1 galaxy NGC 5548, which we obtained in 2004 February at high spatial and spectral resolution with the Space Telescope Imaging Spectrograph (STIS) on the Hubble Space Telescope. We isolate a component of emission with a width of 680 km/s (FWHM) that arises from an "intermediate line region" (ILR), similar to the one we discovered in NGC 4151, at a distance of ~1 pc from the central continuum source. From a detailed analysis of the five intrinsic absorption components in NGC 5548 and their behavior over a span of 8 years, we present evidence that most of the UV absorbers only partially cover the ILR and do not cover an extended region of UV continuum emission, most likely from hot stars in the circumnuclear region. We also find that four of the UV absorbers are at much greater distances (>70 pc) than the ILR, and none have sufficient N V or C IV column densities to be the ILR in absorption. At least a portion of the UV absorption component 3, at a radial velocity of -530 km/s, is likely responsible for most of the X-ray absorption, at a distance < 7 pc from the central source. The fact that we see the ILR in absorption in NGC 4151 and not in NGC 5548 suggests that the ILR is located at a relatively large polar angle (~45 degrees) with respect to the narrow-line region outflow axis.