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arXiv 1606.07192astro-ph.GA
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星团红序星系在过去9 Gyr的形态演化

Morphological evolution of cluster red sequence galaxies in the past 9 Gyr

Roberto De Propris, Malcolm Bremer, Steve Phillipps

摘要:

当星系团的恒星形成过程被淬灭后,星系团到达高红移($z>1$)的红色序列,然后被动地演化。然而,我们以前发现,在过去9-10~Gyr的某个时刻,星团红序星系(CRSG)在恒星形成停止后经历了显著的形态演化。通过对一个大样本的星系团红序列星系的详细研究,我们阐明了这种演化的细节,其中包括$0.2<z<1.4$。低于$z \sim 0.5-0.6$(在最后5-6 Gyr),整个种群很少或没有形态进化,这与之前的4-5 Gyr不同。在这段较早的时间里,(i)具有S{é}rsic $n < 2$的盘状系统逐渐消失,因为(ii)它们的轴比范围类似地减小,去除了最长的系统(这些与在可感知的倾斜角处看到的薄盘一致),和(iii)径向颜色梯度(向外变蓝)从绝对意义上的显著年龄相关梯度下降到与金属丰度一致的残留水平-在低红移星系团成员中观察到的感应梯度。它们的有效半径分布显示出一些演化的证据,与$z\sim 1.4$和$z \sim 0.5$之间的{ \it至多}因子$<1.5$的增长相一致,显著小于可比场星系,而它们的中心($<1$ kpc)凸起表面密度的分布至少在$z<1$没有显示出演化。一个简单的模型,涉及褪色和增厚的磁盘组件后,相对较新的淬火(后$z\sim 1.5$),否则被动演变的旧球体组件是一致的,所有这些发现。

英文摘要:

Galaxies arrive on the red sequences of clusters at high redshift ($z>1$) once their star formation is quenched and evolve passively thereafter. However, we have previously found that cluster red sequence galaxies (CRSGs) undergo significant morphological evolution subsequent to the cessation of star formation, at some point in the past 9-10~Gyr. Through a detailed study of a large sample of cluster red sequence galaxies spanning $0.2<z<1.4$ we elucidate the details of this evolution. Below $z \sim 0.5-0.6$ (in the last 5-6 Gyr) there is little or no morphological evolution in the population as a whole, unlike in the previous 4-5 Gyrs. Over this earlier time (i) disk-like systems with S{é}rsic $n < 2$ progressively disappear, as (ii) the range of their axial ratios similarly decreases, removing the most elongated systems (those consistent with thin disks seen at an appreciable inclination angle), and (iii) radial colour gradients (bluer outwards) decrease in an absolute sense from significant age-related gradients to a residual level consistent with the metallicity-induced gradients seen in low redshift cluster members. The distribution of their effective radii shows some evidence of evolution, consistent with growth of {\it at most} a factor $<1.5$ between $z\sim 1.4$ and $z \sim 0.5$, significantly less than for comparable field galaxies, while the distribution of their central ($<1$kpc) bulge surface densities shows no evolution at least at $z<1$. A simple model involving the fading and thickening of a disk component after comparatively recent quenching (after $z\sim 1.5$) around an otherwise passively evolving older spheroid component is consistent with all of these findings.

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。

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