Star formation suppression and bar ages in nearby barred galaxies
Star formation suppression and bar ages in nearby barred galaxies
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DOI：
10.1093/mnras/stx2990
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发表时间：
2017-11
影响因子：
4.8
通讯作者：
Philip A. James;S. Percival
中科院分区：
文献类型：
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作者：
Philip A. James;S. Percival
我们提出了新的光谱数据的21棒旋星系，我们用它来探讨磁盘上的星星形成酒吧的效果，并把酒吧情节的特征寿命的限制。分析集中在严重抑制星星形成活动的区域，我们称之为“星星形成沙漠”。长缝光谱学用于确定这些沙漠地区的H β吸收强度，并与理论恒星种群模型进行比较，以确定自上次显着的星星形成活动以来的时间，从而确定棒的年龄。我们发现典型的年龄约。1 Gyr，但范围很宽，比仅从测量误差所预期的要大得多，从大约0.25 Gyr延伸到超过4 Gyr。低水平的残余星星形成，或来自“沙漠”地区以外的恒星混合，可能导致这些年龄估计值加倍。相对年轻的年龄，加上目前的星星形成的强烈限制，排除了逐步指数下降的活动，因此支持我们的假设突然截断事件。
We present new spectroscopic data for 21 barred spiral galaxies, which we use to explore the effect of bars on disk star formation, and to place constraints on the characteristic lifetimes of bar episodes. The analysis centres on regions of heavily suppressed star formation activity, which we term 'star formation deserts'. Long-slit optical spectroscopy is used to determine H beta absorption strengths in these desert regions, and comparisons with theoretical stellar population models are used to determine the time since the last significant star formation activity, and hence the ages of the bars. We find typical ages of approx. 1 Gyr, but with a broad range, much larger than would be expected from measurement errors alone, extending from about 0.25 Gyr to more than 4 Gyr. Low-level residual star formation, or mixing of stars from outside the 'desert' regions, could result in a doubling of these age estimates. The relatively young ages of the underlying populations coupled with the strong limits on the current star formation rule out a gradual exponential decline in activity, and hence support our assumption of an abrupt truncation event.