标题： 透镜状星系中的密集分子气体 显示英文标题

标题： Dense Molecular Gas in Lenticular Galaxies

摘要： 我们对透镜状星系 NGC 404、NGC 3593 和 NGC 4293 进行了 CO 和 HCN 的同时观测，并在 NGC 3593 和 NGC 4293 中探测到 HCN 发射，在所有星系中都检测到 CO。NGC 3593 和 NGC 4293 的 I(HCN)/I(CO) 比率分别为 0.025±0.006 和 0.066±0.005，与晚期螺旋星系相当。包括晚期在内的 12 个附近螺旋星系中心的 I(HCN)/I(CO) 平均比率为 0.055±0.028。CO 和 HCN 发射的线轮廓在这两个星系中表现出不同的形状。HCN 峰值不在这些星系的系统速度上，而 CO 峰值接近系统速度。这些结果表明，在这些星系的中心周围，密集分子气体的比例较高。 显示英文摘要

摘要： We made CO and HCN simultaneous observations of lenticular galaxies, NGC 404, NGC 3593 and NGC 4293, and detected HCN emission in NGC 3593 and NGC 4293 as well as CO in all the galaxies. The I(HCN)/I(CO) ratios were 0.025+-0.006 and 0.066+-0.005 in NGC 3593 and NGC 4293, respectively, which are comparable to the late-type spiral galaxies. The average of the I(HCN)/I(CO) ratios at the center of 12 nearby spiral galaxies including late-type was 0.055+-0.028. The line profiles of CO and HCN emission showed different shape in both galaxies. The HCN peaks were not at the systemic velocity of these galaxies, while the CO peaks were near the systemic velocity. These results suggest that the fraction of the dense molecular gas is high around the center in these galaxies.