SAURON项目- XV。早型星系的恒星形成模式与红序演化
The SAURON project - XV. Modes of star formation in early-type galaxies and the evolution of the red sequence
摘要：
我们结合SAURON积分场数据的代表性样本的本地早期型，红序列星系斯皮策/IRAC成像，以调查在这些系统中存在的微量恒星形成。利用斯皮策的数据，我们识别出了存在低水平恒星形成的星系，正如多环芳烃发射所追踪的那样，测得的恒星形成率与其他示踪剂估计的恒星形成率相当。这种恒星形成的进展，根据建立的缩放关系与分子气体含量，在表面密度制度的特点盘星系和环核星爆。我们发现，在早期型星系的恒星形成只发生在快速旋转的系统，并发生在两个不同的模式。在第一种情况下，恒星的形成是一个扩散的过程，对应于广泛的年轻恒星星族和高分子气体含量。平等存在的共同和反旋转的组件在这些系统中强烈意味着外部起源的恒星形成的气体，我们认为，这些恒星形成事件可能是最后阶段的合并（主要是轻微的），建立了隆起的红色序列望远镜。在第二种恒星形成模式中，这个过程集中在定义明确的盘或环形态中，在这些形态之外，宿主星系表现出均匀演化的恒星星族。这意味着这些恒星形成事件代表了先前静止的恒星系统中的年轻化。早期恒星形成事件的证据与所有快速旋转的早型星系类似，表明这种恒星形成模式可能是所有此类星系所共有的，占空比约为1/10，并且可能有助于嵌入，共同旋转的内部恒星盘在这个群体中无处不在。
英文摘要：
We combine SAURON integral field data of a representative sample of local early-type, red sequence galaxies with Spitzer/IRAC imaging in order to investigate the presence of trace star formation in these systems. With the Spitzer data, we identify galaxies hosting low-level star formation, as traced by PAH emission, with measured star formation rates that compare well to those estimated from other tracers. This star formation proceeds according to established scaling relations with molecular gas content, in surface density regimes characteristic of disk galaxies and circumnuclear starbursts. We find that star formation in early-type galaxies happens exclusively in fast-rotating systems and occurs in two distinct modes. In the first, star formation is a diffuse process, corresponding to widespread young stellar populations and high molecular gas content. The equal presence of co- and counter-rotating components in these systems strongly implies an external origin for the star-forming gas, and we argue that these star formation events may be the final stages of (mostly minor) mergers that build up the bulges of red sequence lenticulars. In the second mode of star formation, the process is concentrated into well-defined disk or ring morphologies, outside of which the host galaxies exhibit uniformly evolved stellar populations. This implies that these star formation events represent rejuvenations within previously quiescent stellar systems. Evidence for earlier star formation events similar to these in all fast rotating early-type galaxies suggests that this mode of star formation may be common to all such galaxies, with a duty cycle of roughly 1/10, and likely contributes to the embedded, co-rotating inner stellar disks ubiquitous in this population.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
