The Environments of High Redshift QSOs
The Environments of High Redshift QSOs
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高红移 QSO 的环境
DOI：
10.1088/0004-637x/695/2/809
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
G. Meylan
中科院分区：
文献类型：
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作者：
Soyoung Kim;M. Stiavelli;M. Trenti;C.M.Pavlovsky;S. Djorgovski;C. Scarlata;D. Stern;A. Mahabal;D. Thompson;M. Dickinson;N. Panagia;G. Meylan
我们展示了在5个哈勃高级巡天相机领域中发现的$i_{775}$-dropout候选者的样本，这些候选者集中在红移$z\sim 6$的斯隆数字巡天QSOs上。我们的区域与大天文台起源深度调查（GOODS） ACS图像一样深，用作参考区域样本。我们发现它们在两个领域中密度过大，在两个领域中密度过低，在一个领域中密度与GOODS的平均密度相当。在99%的置信水平上，两个多余的场显示出与GOODS明显不同的颜色分布，加强了多余物体确实与QSO相关的想法。在80%到96%的置信水平上，这五个领域中$i_{775}$-dropout计数的分布比从GOODS得出的分布更广泛，这取决于采用哪种选择标准来识别$i_{775}$-dropout；它的宽度不能仅仅用宇宙方差来解释。因此，qso似乎以复杂的方式影响它们的环境。我们建议的图片中，最高的红移qso位于非常大质量的超密度中，因此被低质量的超密度晕包围。QSO的辐射反馈在某些情况下可以阻止晕变成星系，从而在极端情况下产生星系密度不足。增强和抑制的存在与再电离结束时视线之间的预期差异是相容的，因为残余弥漫性中性氢的存在将为年轻星系提供屏蔽QSO辐射效应的屏障。
We present a sample of $i_{775}$-dropout candidates identified in five Hubble Advanced Camera for Surveys fields centered on Sloan Digital Sky Survey QSOs at redshift $z\sim 6$. Our fields are as deep as the Great Observatory Origins Deep Survey (GOODS) ACS images which are used as a reference field sample. We find them to be overdense in two fields, underdense in two fields, and as dense as the average density of GOODS in one field. The two excess fields show significantly different color distributions from that of GOODS at the 99% confidence level, strengthening the idea that the excess objects are indeed associated with the QSO. The distribution of $i_{775}$-dropout counts in the five fields is broader than that derived from GOODS at the 80% to 96% confidence level, depending on which selection criteria were adopted to identify $i_{775}$-dropouts; its width cannot be explained by cosmic variance alone. Thus, QSOs seem to affect their environments in complex ways. We suggest the picture where the highest redshift QSOs are located in very massive overdensities and are therefore surrounded by an overdensity of lower mass halos. Radiative feedback by the QSO can in some cases prevent halos from becoming galaxies, thereby generating in extreme cases an underdensity of galaxies. The presence of both enhancement and suppression is compatible with the expected differences between lines of sight at the end of reionization as the presence of residual diffuse neutral hydrogen would provide young galaxies with shielding from the radiative effects of the QSO.