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arXiv 1505.02802astro-ph.GA
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横斑宁静星系的恒星星族

Stellar Populations of Barred Quiescent Galaxies

Edmond Cheung, Charlie Conroy, E. Athanassoula, Eric F. Bell, A. Bosma, Carolin N. Cardamone, S. M. Faber, David C. Koo, Chris Lintott, Karen L. Masters, Thomas… 展开作者

Edmond Cheung, Charlie Conroy, E. Athanassoula, Eric F. Bell, A. Bosma, Carolin N. Cardamone, S. M. Faber, David C. Koo, Chris Lintott, Karen L. Masters, Thomas Melvin, Brooke Simmons, Kyle W. Willett

摘要:

从斯隆数字巡天(SDSS)中选择中心静止星系,以创建具有最小发射线污染的高信噪比(>100)堆叠光谱,我们准确和精确地模拟了棒斑和非棒斑静止盘星系的中心恒星星族。通过用红移分裂我们的样本,我们可以使用固定尺寸的SDSS光纤来模拟星系内不同半径的恒星星族。在0.02<z<0.04时,SDSS纤维半径对应于~1 kpc,这是经典凸起和盘状伪凸起的典型半光半径。假设SDSS光纤主要覆盖了这些红移处的凸起,我们的分析表明,恒星星族之间没有显着差异,即,恒星年龄,[Fe/H],[Mg/Fe],和[N/Fe],有棒与无棒静止盘星系的凸起。在固定的恒星质量下,从z=0.020到z=0.085的不同红移间隔下对恒星星族进行建模,得到了恒星星族梯度的估计值,该梯度约为我们样本典型有效半径的一半,假设在这个~1 Gyr时代的演化为零。我们发现,有棒与无棒静止盘星系的方位角平均梯度的斜率没有明显的差异。这些结果表明,酒吧是不是一个很强的影响化学演化的静止盘星系。

英文摘要:

Selecting centrally quiescent galaxies from the Sloan Digital Sky Survey (SDSS) to create high signal-to-noise (>100) stacked spectra with minimal emission line contamination, we accurately and precisely model the central stellar populations of barred and unbarred quiescent disk galaxies. By splitting our sample by redshift, we can use the fixed size of the SDSS fiber to model the stellar populations at different radii within galaxies. At 0.02<z<0.04, the SDSS fiber radius corresponds to ~1 kpc, which is the typical half-light radii of both classical bulges and disky pseudobulges. Assuming that the SDSS fiber primarily covers the bulges at these redshifts, our analysis shows that there are no significant differences in the stellar populations, i.e., stellar age, [Fe/H], [Mg/Fe], and [N/Fe], of the bulges of barred vs. unbarred quiescent disk galaxies. Modeling the stellar populations at different redshift intervals from z=0.020 to z=0.085 at fixed stellar masses produces an estimate of the stellar population gradients out to about half the typical effective radius of our sample, assuming null evolution over this ~1 Gyr epoch. We find that there are no noticeable differences in the slopes of the azimuthally averaged gradients of barred vs. unbarred quiescent disk galaxies. These results suggest that bars are not a strong influence on the chemical evolution of quiescent disk galaxies.

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