在$25\kpch$上从一个完整的双星样本进行类星体聚类
Quasar Clustering at $25\kpch$ from a Complete Sample of Binaries
摘要：
我们提出了光谱的二进制类星体候选人选择从数据发布4的斯隆数字巡天（SDSS DR 4）使用核密度估计（KDE）。我们提出了27组新的观测结果，其中10个是二元类星体，大约是已知的$g < 21$二元类星体数量的两倍，其成分分离为3至6”。在49个被光谱识别的天体中，只有3个是非类星体，证实了KDE技术的类星体选择效率为$\sim95$ %。我们观察到的几个双星是宽分离透镜候选者，值得额外的更高分辨率的观测。一个有趣的配对可能是M星双星，或者是M星双星类星体的叠加。我们的候选人最初选择的紫外线过剩（$u-g < 1$），但在其他方面选择的类星体对的相对颜色无关，因此，我们使用它们来建议最佳的颜色相似性和光度红移的方法，针对二元类星体，或投影类星体对。从一个样本是完整的适当尺度的$23.7 < R_{prop} < 29.7\kpch$，我们确定的投影类星体的相关函数是$W_p=24.0 \pm^{16.9}_{10.8}$，这是$2σ$低于最近的估计。我们认为，我们的低$W_p$估计可能表明红移的演化类星体的相关函数从$z\sim1.9$到$z\sim1.4$的尺度上的$R_{prop} \sim25\kpch$。这种演化的规模在更大的尺度上广泛地跟踪类星体集群，与合并驱动的类星体起源模型一致。虽然我们的样本本身不足以检测小尺度上类星体集群的演化，但$i$选择的DR6 KDE类星体目录（将包含数百个$z \leqsim 5$二元类星体）可以很容易地限制$R_{prop} \sim25\kpch$上的任何集群演化。
英文摘要：
We present spectroscopy of binary quasar candidates selected from Data Release 4 of the Sloan Digital Sky Survey (SDSS DR4) using Kernel Density Estimation (KDE). We present 27 new sets of observations, 10 of which are binary quasars, roughly doubling the number of known $g < 21$ binaries with component separations of 3 to 6". Only 3 of 49 spectroscopically identified objects are non-quasars, confirming that the quasar selection efficiency of the KDE technique is $\sim95$%. Several of our observed binaries are wide-separation lens candidates that merit additional higher-resolution observations. One interesting pair may be an M star binary, or an M star-binary quasar superposition. Our candidates are initially selected by UV-excess ($u-g < 1$), but are otherwise selected irrespective of the relative colors of the quasar pair, and we thus use them to suggest optimal color similarity and photometric redshift approaches for targeting binary quasars, or projected quasar pairs. From a sample that is complete on proper scales of $23.7 < R_{prop} < 29.7\kpch$, we determine the projected quasar correlation function to be $W_p=24.0 \pm^{16.9}_{10.8}$, which is $2σ$ lower than recent estimates. We argue that our low $W_p$ estimates may indicate redshift evolution in the quasar correlation function from $z\sim1.9$ to $z\sim1.4$ on scales of $R_{prop} \sim25\kpch$. The size of this evolution broadly tracks quasar clustering on larger scales, consistent with merger-driven models of quasar origin. Although our sample alone is insufficient to detect evolution in quasar clustering on small scales, an $i$-selected DR6 KDE quasar catalog, which will contain several hundred $z \leqsim 5$ binary quasars, could easily constrain any clustering evolution at $R_{prop} \sim25\kpch$.
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。
