标题： 星系核分子气体（NUGA）项目第三部分。 具有翘曲LINER的NGC3718 显示英文标题

标题： Molecular Gas in NUclei of GAlaxies (NUGA) III. The warped LINER NGC3718

摘要： 我们展示了首次使用 IRAM PdBI 对弯曲 LINER 星系 NGC3718 的 CO(1-0) 和 CO(2-1) 线发射的干涉观测结果。 这个 L1.9 星系具有显著的尘埃带，在千秒差距尺度上，其原子和分子气体盘强烈弯曲。 分子气体与穿过核区的尘埃带密切相关，其动力学中心与毫米波连续谱 AGN 一致。 我们将完全覆盖 ~9 千秒差距弯曲盘的干涉镶嵌数据与之前获得的 IRAM 30 米单碟 CO(1-0) 图像进行比较，发现盘中的分子气体分布被 PdBI 映射严重解析。 在应用了短间距校正后，我们在尘埃带内发现了总共六个主要源成分：一个与核区相关，四个对称地位于距离中心约 1.3 千秒差距和 4.0 千秒差距的地方，以及第六个位于西部约 3 千秒差距处，仅有非常弱的东部对应物。 在使用倾斜环模型的动力学框架下，我们将五个对称源成分解释为强轨道拥挤的位置。 我们进一步发现，弯曲不仅出现在千秒差距尺度上，而且一直延伸到 250 秒差距。 除了西部的第六个特征外，东部成分的通量低于西部成分，表明 NGC3718 存在一个无法由弯曲解释的大尺度不对称性。 在中心 600 秒差距范围内也观察到了小尺度不对称性的迹象。 这些不对称性可能是伴星系潮汐相互作用（大尺度）和核区气体吸积（小尺度）的证据。 我们对 NGC3718 的研究是 NUGA 项目的一部分，该项目旨在调查气体向 AGN 吸积的不同过程。 显示英文摘要

摘要： We present the first interferometric observations of CO(1-0) and CO(2-1) line emission from the warped LINER NGC3718, obtained with the IRAM PdBI. This L1.9 galaxy has a prominent dust lane and on kpc scales, a strongly warped atomic and molecular gas disk. The molecular gas is closely associated with the dust lane across the nucleus and its kinematic center is consistent with the mm continuum AGN. A comparison of our interferometric mosaic data, which fully cover the ~9kpc warped disk, with a previously obtained IRAM 30m single dish CO(1-0) map shows that the molecular gas distribution in the disk is heavily resolved by the PdBI map. After applying a short-spacing correction with the IRAM 30m data, we find in total six main source components within the dust lane: one associated with the nucleus, four symmetrically positioned on either side at galactocentric distances of about 1.3kpc and 4.0kpc from the center, and a sixth on the western side at ~3kpc with only a very weak eastern counterpart. In the framework of a kinematic model using tilted rings, we interpret the five symmetric source components as locations of strong orbital crowding. We further find indications that the warp appears not only on kpc scales, but continues down to 250pc. Besides the sixth feature on the western side, the lower flux of the eastern components compared to the western ones indicates an intrinsic large scale asymmetry in NGC3718 that cannot be explained by the warp. Indications for a small scale asymmetry are also seen in the central 600pc. These asymmetries might be evidence for a tidal interaction with a companion galaxy (large scales) and gas accretion onto the nucleus (small scales). Our study of NGC3718 is part of the NUGA project that aims at investigating the different processes of gas accretion onto AGN.