标题： HCG31 是否正在经历星系合并或飞掠相互作用？ 显示英文标题

标题： Is HCG31 undergoing a merger or a fly-by interaction?

摘要： 我们展示了对致密星系群Hickson 31（HCG31）中星系的法布里-珀罗干涉仪和多目标光谱观测结果。基于我们的H$\alpha$数据立方体，星系A和C是一个单一实体，它们的运动学没有间断。从运动学上看，星系E可能是A+C复合体的一个组成部分；否则它是一个最近分离出来的碎片。星系F无论是在运动学上还是化学成分上都似乎是由从A+C复合体潮汐剥离的物质形成的。星系B和G在运动学上与这个复合体不同。星系Q也具有与群成员相符的径向速度。尽管亮度范围跨度达到5$ $个星等，星系A、B、C和F几乎具有相同的氧丰度。星系B的氧丰度与其亮度相符，而星系F的丰度则符合其作为A+C复合体潮汐碎片起源的预期。如果A+C复合体是一个遭受强烈气体流入和恒星形成活动的晚期旋涡星系，那么星系A和C的氧丰度也可以理解。考虑到星系和\ion{H}{i}气体的运动学、氧丰度以及星系G的位置，我们认为星系G与A+C复合体的相互作用，而不是星系A和C的合并，是对HCG31潮汐特征和其他性质更完整的解释。在这种情况下，A+C复合体不需要是一个正在进行中的合并过程，但这一点并未被排除。 显示英文摘要

摘要： We present Fabry-Perot and multi-object spectroscopy of the galaxies in Hickson compact group 31 (HCG31). Based upon our H$\alpha$ data cubes, galaxies A and C are a single entity, showing no discontinuity in their kinematics. Kinematically, galaxy E is probably a component of the A+C complex; otherwise it is a recently detached fragment. Galaxy F appears, both kinematically and chemically, to have formed from material tidally removed from the A+C complex. Galaxies B and G are kinematically distinct from this complex. Galaxy Q also has a radial velocity compatible with group membership. Galaxies A, B, C, and F have nearly identical oxygen abundances, despite spanning a luminosity range of 5$ $mag. Galaxy B's oxygen abundance is normal for its luminosity, while galaxy F's abundance is that expected given its origin as a tidal fragment of the A+C complex. The oxygen abundances in galaxies A and C are also understandable if the A+C complex is a late-type spiral suffering strong gas inflow and star formation as a result of a tidal interaction. Given the kinematics of both the galaxies and the \ion{H}{i} gas, the oxygen abundances, and the position of galaxy G, we propose that an interaction of galaxy G with the A+C complex, rather than a merger of galaxies A and C, is a more complete explanation for the tidal features and other properties of HCG31. In this case, the A+C complex need not be a merger in progress, though this is not ruled out.