z ~ 0.5范围内星系团红序巨矮星比的演化
Evolution of the Red Sequence Giant to Dwarf Ratio in Galaxy Clusters out to z ~ 0.5
摘要：
我们分析了加拿大-法国-夏威夷望远镜MegaCam拍摄的97个星系团的深g'和r'波段数据。我们使用基于de Lucia et al.（2007）定义的标准计算了发光（巨）和暗淡（矮）星系的数量。由于出色的图像质量和数据和分析的均匀性，我们探测到z ~ 0.55的巨矮星比（GDR）。与X射线温度（Tx）的信息，我们的大部分集群，我们约束，第一次，Tx校正的巨人和矮演化分别。我们的测量结果支持在红移范围0.05 < z < 0.55的GDR的发展。我们表明，修改（g '-r'），m_r'和K-校正用于定义侏儒和巨人的选择不改变的结论，关于进化的存在。我们使用红移的线性函数（GDR = alpha * z + beta）来参数化GDR演化，其中最佳拟合斜率为alpha = 0.88 +/- 0.15并且归一化beta = 0.44 +/- 0.03。相反，声称一个大的内在散射，我们发现，GDR数据可以完全占使用观测误差。一致的，我们没有发现GDR和集群质量（通过Tx或弱透镜）之间的相关性的证据。最后，数据表明，在z < 0.2时，GDR的演化主要是由大质量巨星系的干合并驱动的，当考虑到以前在高红移时的结果时，这表明介导GDR的主导机制发生了变化。
英文摘要：
We analyze deep g' and r' band data of 97 galaxy clusters imaged with MegaCam on the Canada-France-Hawaii telescope. We compute the number of luminous (giant) and faint (dwarf) galaxies using criteria based on the definitions of de Lucia et al. (2007). Due to excellent image quality and uniformity of the data and analysis, we probe the giant-to-dwarf ratio (GDR) out to z ~ 0.55. With X-ray temperature (Tx) information for the majority of our clusters, we constrain, for the first time, the Tx-corrected giant and dwarf evolution separately. Our measurements support an evolving GDR over the redshift range 0.05 < z < 0.55. We show that modifying the (g'-r'), m_r' and K-correction used to define dwarf and giant selection do not alter the conclusion regarding the presence of evolution. We parameterize the GDR evolution using a linear function of redshift (GDR = alpha * z + beta) with a best fit slope of alpha = 0.88 +/- 0.15 and normalization beta = 0.44 +/- 0.03. Contrary to claims of a large intrinsic scatter, we find that the GDR data can be fully accounted for using observational errors alone. Consistently, we find no evidence for a correlation between GDR and cluster mass (via Tx or weak lensing). Lastly, the data suggest that the evolution of the GDR at z < 0.2 is driven primarily by dry merging of the massive giant galaxies, which when considered with previous results at higher redshift, suggests a change in the dominant mechanism that mediates the GDR.
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。
