标题： Mrk231分子外流中的增强紫外辐射和密集团块 显示英文标题

标题： Enhanced UV radiation and dense clumps in Mrk231's molecular outflow

摘要： 我们展示了对 Mrk231 中 CN(1-0) 线发射的干涉观测，并将其与之前对 CO 和其他 H$_2$气体示踪剂的观测相结合，以研究大质量分子外流的物理特性。我们发现外流中 CN/CO(1-0) 线亮度比有强烈的增强，这与其他已知的银河系或星系际源相比是前所未有的。对于由 HCN 和 CN 发射示踪的外流密集气体相，我们推断 H$\rm X_{\rm CN}\equiv [CN]/[H_2] > X_{\rm HCN}$至少增加了三倍，H$_2$气体密度达到$n_{\rm H_2}\sim10^{5-6}$cm$^{-3}$。此外，首次在外流密集相位的 HCN(1-0) 和 HCO$^+$(1-0) 高速线翼中解析出窄谱特征。 这些光谱特征的速度弥散， $\sigma_v\sim7-20$公里每秒$^{-1}$，与附近星暴核区探测到的巨型分子云的速度弥散一致。 从HCN数据推断出的H$_2$气体质量相当高， $M_{mol}\sim0.3-5\times10^8$ $M_{\odot}$ 。 我们的研究结果表明，大质量、更致密的分子气体复合体能够嵌入外流中更为弥散的H$_2$相中得以幸存，并且这种外流致密云的化学性质会受到增强的紫外辐射的影响。 显示英文摘要

摘要： We present interferometric observations of the CN(1-0) line emission in Mrk231 and combine them with previous observations of CO and other H$_2$ gas tracers to study the physical properties of the massive molecular outflow. We find a strong boost of the CN/CO(1-0) line luminosity ratio in the outflow, which is unprecedented compared to any other known Galactic or extragalactic source. For the dense gas phase in the outflow traced by the HCN and CN emissions, we infer $\rm X_{\rm CN}\equiv [CN]/[H_2] > X_{\rm HCN}$ by at least a factor of three, with H$_2$ gas densities of $n_{\rm H_2}\sim10^{5-6}$ cm$^{-3}$. In addition, for the first time, we resolve narrow spectral features in the HCN(1-0) and HCO$^+$(1-0) high-velocity line wings tracing the dense phase of the outflow. The velocity dispersions of these spectral features, $\sigma_v\sim7-20$ km s$^{-1}$, are consistent with those of massive extragalactic giant molecular clouds detected in nearby starburst nuclei. The H$_2$ gas masses inferred from the HCN data are quite high, $M_{mol}\sim0.3-5\times10^8$ $M_{\odot}$. Our results suggest that massive, denser molecular gas complexes survive embedded into the more diffuse H$_2$ phase of the outflow, and that the chemistry of such outflowing dense clouds is affected by enhanced UV radiation.