TRIGGERED STAR FORMATION IN GALAXY PAIRS AT z = 0.08–0.38
TRIGGERED STAR FORMATION IN GALAXY PAIRS AT z = 0.08–0.38
复制标题
DOI：
10.1088/0004-6256/139/5/1857
复制
发表时间：
2010-02
期刊：
影响因子：
--
通讯作者：
D. Woods;M. Geller;Michael J. Kurtz;E. Westra;D. Fabricant;I. Dell’Antonio
中科院分区：
文献类型：
--
作者：
D. Woods;M. Geller;Michael J. Kurtz;E. Westra;D. Fabricant;I. Dell’Antonio
我们测量了红移z = 0.08-0.38的潮汐触发星星形成的强度、频率和时间尺度，这些样本是从9825个史密森Hectospec Lensing Survey星系的限星等红移巡天中抽取的光谱完整样本，这些星系对的R 1/5）对星系在红移z = 0.08-0.31范围内MR <-20.8。光谱测量的规模和完整性使我们能够专注于低局部密度的区域。分光光度计定标使得能够使用4000 μ s的破裂（Dn 4000）、Hα特定星星形成率（SSFRHα）和星族模型来表征星系。我们表明，DN 4000是一个有用的人口分类工具，它密切跟踪识别发射线星系。低局部密度与低Dn 4000的区域中的主要对星系的样本表明，在以前的研究中探索的一组星星形成指标的成对投影分离和预期的反相关。我们通过比较低局域密度区域的体积有限样本中的SSFRHα来测量触发星星形成的频率：32% ± 7%的主要成对星系的SSFRHα至少是未成对场星系的中值速率的两倍。比较成对和非成对场星系的恒星种群模型，暗示触发星星形成的时间尺度为300-400万年。
We measure the strength, frequency, and timescale of tidally triggered star formation at redshift z = 0.08–0.38 in a spectroscopically complete sample of galaxy pairs drawn from the magnitude-limited redshift survey of 9825 Smithsonian Hectospec Lensing Survey galaxies with R 1/5) pair galaxies with MR < −20.8 in the redshift range z = 0.08–0.31. The size and completeness of the spectroscopic survey allow us to focus on regions of low local density. The spectrophotometric calibration enables the use of the 4000 Å break (Dn4000), the Hα specific star formation rate (SSFRHα), and population models to characterize the galaxies. We show that Dn4000 is a useful population classification tool; it closely tracks the identification of emission line galaxies. The sample of major pair galaxies in regions of low local density with low Dn4000 demonstrates the expected anti-correlation between pairwise projected separation and a set of star formation indicators explored in previous studies. We measure the frequency of triggered star formation by comparing the SSFRHα in the volume-limited sample in regions of low local density: 32% ± 7% of the major pair galaxies have SSFRHα at least double the median rate of the unpaired field galaxies. Comparison of stellar population models for pair and for unpaired field galaxies implies a timescale for triggered star formation of ∼300–400 Myr.