标题： 将层次聚类模型与星系对观测结果相对比 显示英文标题

标题： Confronting Hierarchical Clustering Models with Observations of Galaxy Pairs

摘要： 我们研究了符合Λ冷暗物质（Lambda-CDM）情景的化学流体动力学模拟中的星系对的恒星形成活动。 统计分析表明，星系相互作用对恒星形成活动的影响与轨道参数有关，近距离遭遇（r < 30 kpc/h）相对于没有近邻伴星的星系可以有效地增强恒星形成活动。 我们的结果显示，系统的稳定性属性在这个过程中也起着重要作用。 我们发现，被动恒星形成的星系对倾向于比活跃恒星形成的星系对具有更深的引力势阱、更老的恒星群体和更少的剩余气体。 为了评估投影效应和闯入者可能对观测样本引入的影响，我们还构建并分析了星系对的投影模拟目录。 与观测结果一致，我们的结果显示，对于近距离遭遇（rp < 25 kpc/h），相比于没有近邻伴星的星系，相互作用可以增强恒星形成活动。 最后，分析环境效应时，我们检测到星系对和孤立星系样本都存在预期的恒星形成率（SFR）-局部密度关系，尽管这一关系的密度依赖性在星系对中更强，表明相互作用在驱动该关系中起着重要作用。 显示英文摘要

摘要： We investigate the star formation activity in galaxy pairs in chemical hydrodynamical simulations consistent with a Lambda-CDM scenario. A statistical analysis of the effects of galaxy interactions on the star formation activity as a function of orbital parameters shows that close encounters (r < 30 kpc/h) can be effectively correlated with an enhancement of star formation activity with respect to galaxies without a close companion. Our results suggest that the stability properties of systems are also relevant in this process. We found that the passive star forming galaxies pairs tend to have deeper potential wells, older stellar populations, and less leftover gas than active star forming ones. In order to assess the effects that projection and interlopers could introduce in observational samples, we have also constructed and analysed projected simulated catalogs of galaxy pairs. In good agreement with observations, our results show a threshold (rp < 25 kpc/h) for interactions to enhance the star formation activity with respect to galaxies without a close companion. Finally, analysing the environmental effect, we detect the expected SFR-local density relation for both pairs and isolated galaxy samples, although the density dependence is stronger for galaxies in pairs suggesting a relevant role for interactions in driving this relation.