论文标题
跨宇宙时代的合并starburst连接
The merger-starburst connection across cosmic times
论文作者
论文摘要
星系主要合并与Starburst活性之间的对应关系在观察方面是完善的，并且在低红移星系的模拟中。但是，相互作用和涉及星系的性质的演变表明，星系对合并事件的星爆反应可能在宇宙时间内有所不同。使用vintergatan宇宙缩放模拟类似银河系的银河系，我们在这里表明，starbursts，即快恒星形成的发作，与潮汐压缩的开始相关，这本身是由合并引起的。但是，这种压缩才能足够强大，只有在银河盘形成后才能触发Starbursts。结果，只有在星系进化的精确阶段，盘形成之后和最后一次主要合并之后才能发现Starburst发作。由于耗竭时间量化了瞬时恒星形成活性，而特定的恒星形成速率涉及过去活性的综合结果（通过恒星质量），Starburst发作不一定与升高的特异性星形形成率相吻合。这表明并非全部的星堡星系都超过了星系组的主要序列。
The correspondence between galaxy major mergers and starburst activity is well-established observationally and in simulations of low redshift galaxies. However, the evolution of the properties of interactions and of the galaxies involved suggests that the starburst response of galaxies to merger events could vary across cosmic time. Using the VINTERGATAN cosmological zoom-in simulation of a Milky Way-like galaxy, we show here that starbursts, i.e. episodes of fast star formation, are connected with the onset of tidal compression, itself induced by mergers. However, this compression becomes strong enough to trigger starbursts only after the formation of the galactic disc. As a consequence, starburst episodes are only found during a precise phase of galaxy evolution, after the formation of the disc and until the last major merger. As the depletion time quantifies the instantaneous star formation activity, while the specific star formation rate involves the integrated result of the past activity (via the stellar mass), starburst episodes do not necessarily coincide with elevated specific star formation rate. This suggests that not all starburst galaxies are outliers above the main sequence of galaxy formation.
