Determining the Lensing Fraction of SDSS Quasars: Methods and Results from the Early Data Release
Determining the Lensing Fraction of SDSS Quasars: Methods and Results from the Early Data Release
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确定 SDSS 类星体的透镜分数：早期数据发布的方法和结果
DOI：
10.1086/374233
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发表时间：
2003
期刊：
影响因子：
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通讯作者：
J. Brinkmann
中科院分区：
文献类型：
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作者：
B. Pindor;E. Turner;R. Lupton;J. Brinkmann
提出了一种从斯隆数字巡天（SDSS）类星体中选择引力透镜候选者的算法。在早期数据发布（EDR）的中值条件下，该算法允许恢复的等通量点源对的分离下至1.00.″7或通量比高达1.10：1，分离1.″5。该算法还恢复了各种各样的似是而非的四边形几何形状。我们还提出了一种方法，通过使用模拟SDSS图像确定该算法的选择函数，并介绍了一种方法，通过真实性测试与真实的SDSS数据校准我们的模拟图像。最后，我们应用我们的算法和选择函数的SDSS类星体从EDR得到的透镜分数的上限。我们在5120个z > 0.6的SDSS类星体中发现了13个候选者，这意味着观测到的透镜分数不超过4 × 10-3。在我们的最终样品中有一个可能的透镜系统，这意味着观察到的透镜分数不小于3 × 10-5（95%置信水平）。
We present an algorithm for selecting gravitational lens candidates from among Sloan Digital Sky Survey (SDSS) quasars. In median Early Data Release (EDR) conditions, the algorithm allows for the recovery of pairs of equal flux point sources down to separations of ∼0.″7 or with flux ratios up to ∼10 : 1 at a separation of 1.″5. The algorithm also recovers a wide variety of plausible quad geometries. We also present a method for determining the selection function of this algorithm through the use of simulated SDSS images and introduce a method for calibrating our simulated images through truth testing with real SDSS data. Finally, we apply our algorithm and selection function to SDSS quasars from the EDR to get an upper bound on the lensing fraction. We find 13 candidates among 5120 z > 0.6 SDSS quasars, implying an observed lensing fraction of not more than 4 × 10-3. There is one likely lens system in our final sample, implying an observed lensing fraction of not less than 3 × 10-5 (95% confidence levels).