标题： 射电安静类星体环境 - I。 类星体与bj<23星系的相关性 显示英文标题

标题： Radio-quiet QSO environments - I. The correlation of QSOs and bj<23 galaxies

摘要： 在本文中，我们展示了对射电安静类星体环境的分析结果。 目的是确定类星体与星系之间的关系随红移的变化。 我们将来自光学和X射线选择目录的约150个类星体样本与暗弱星系（bj<23）进行交叉相关。 这些数据使我们能够探测类星体的星系聚类环境，直到z~1.0-1.5。 远非正相关，在z<1.5时，类星体-星系交叉相关函数略为负，w(theta<120'')=-0.027+-0.020。 颜色信息表明，反相关在类星体与红色星系群体之间最为显著。 我们构建了模型来预测类星体-星系交叉相关，使用已知的bj<23时的星系N(z)形式，并假设各种聚类演化速率。 类星体存在于丰富星系团环境中的情况被超过5sigma排除，结果更符合射电安静类星体的“正常”星系环境。 如果将小的反相关解释为引力透镜效应，这一结论不会改变。 在这种情况下，数据仅比低聚类幅度模型低约1sigma，而高幅度模型仍然被舒适地排除。 因此，我们得出结论，这些类星体可能并不比光学选择的星系具有更高的偏差。 显示英文摘要

摘要： In this paper we present results of an analysis of radio-quiet QSO environments. The aim is to determine the relation between QSOs and galaxies as a function of redshift. We cross-correlate a sample of ~150 QSOs from optically and X-ray selected catalogues with faint, bj<23, galaxies. These data allow us to probe the galaxy clustering environment of QSOs out to z~1.0-1.5. Far from giving a positive correlation, at z<1.5 the QSO-galaxy cross-correlation function is marginally negative, with w(theta<120'')=-0.027+-0.020. Colour information suggests that the anti-correlation is most significant between the QSOs and the red galaxy population. We have constructed models to predict the QSO-galaxy cross-correlation, using the known form of the galaxy N(z) at bj<23, and assuming a variety of clustering evolution rates. Cases in which QSOs exist in rich cluster environments are comfortably ruled out at more than 5sigma and the results are more consistent with a `normal' galaxy environment for radio-quiet QSOs. If the small anti-correlation is interpreted as an effect of gravitational lensing, this conclusion is not altered. In this case, the data are only ~1sigma below the low clustering amplitude models, while the high amplitude models are still comfortably rejected. We therefore conclude that these QSOs may not be much more highly biased than optically selected galaxies.