标题： NGC 4261中的薄HI核周盘 显示英文标题

标题： A Thin HI Circumnuclear Disk in NGC4261

摘要： 我们报告了对射电星系NGC4261中的HI吸收特征进行的高灵敏度、光谱线VLBI观测结果。尽管吸收仅能在最敏感的基线上被探测到，但它可以明确地与反喷流相关联，并被认为起源于一个薄的原子核外晕盘。这一结构很可能延续了从哈勃太空望远镜成像推断出的尘埃吸积盘，该盘可能正在为超大质量黑洞提供物质。计算得出反喷流前方的HI柱密度约为 10^{21}(T_sp/100 K) cm^{-2}，这与X射线数据和VLBI尺度上的自由-自由吸收一致。这里呈现的数据是首个在新的EVN MkIV数据处理器上处理的科学项目的成果。 显示英文摘要

摘要： We report on high sensitivity, spectral line VLBI observations of the HI absorption feature in the radio galaxy NGC4261. Although absorption is only detectable on the most sensitive baseline, it can be unambiguously associated with the counterjet and is interpreted to originate in a thin atomic circumnuclear disk. This structure is probably a continuation of the dusty accretion disk inferred from HST imaging, which could be feeding the massive black hole. HI column densities in front of the counterjet of the order of 10^{21}(T_sp/100 K) cm^{-2} are derived, consistent with X-ray data and VLBI scale free-free absorption. The data presented here are the result of the first scientific project processed on the new EVN MkIV data processor.