Population mixtures and searches of lensed and extended quasars across photometric surveys
Population mixtures and searches of lensed and extended quasars across photometric surveys
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光度调查中透镜类星体和扩展类星体的种群混合和搜索
DOI：
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
T. Treu
中科院分区：
文献类型：
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作者：
P. Williams;A. Agnello;T. Treu
宽视场测光巡天可以搜寻稀有但有趣的天体，例如强透镜类星体或拥有明亮宿主星系的类星体。过去基于光学和近红外特性的透镜类星体搜索依赖于光度切割和光谱预选（如斯隆类星体透镜搜索），或应用于光度样本的神经网络。这些方法依赖于形态和颜色的削减，由于其人口属性的分散，限制性的训练集，基于星表的星等的系统不确定性，以及测量到测量的光度变化，可能会丢失许多有趣的对象。在这里，我们探讨了高斯混合模型的性能，以分离点状类星体，类星体与扩展主机，和强透镜类星体使用griz psf和模型幅度和WISE W1，W2。选择光学星等是因为它们存在于所有当前和即将发布的宽场调查中，而紫外线信息并不总是可用的。然后，我们评估蓝色星系的污染和额外的功能，如W3的幅度或PSF模型项的形态信息的作用。作为演示，我们在SDSS足迹的随机10%中进行搜索，并且我们提供了在我们的选择中具有最高“透镜”分数的43个SDSS对象的目录，这些SDSS对象经受住了目视检查，并且通过光谱确认为宿主活性核。我们检查了档案数据，并在哈勃遗产档案中找到了5/43物体的图像，包括2个已知的镜头。守则和资料可供参考，以方便跟进。
Wide-field photometric surveys enable searches of rare yet interesting objects, such as strongly lensed quasars or quasars with a bright host galaxy. Past searches for lensed quasars based on their optical and near infrared properties have relied on photometric cuts and spectroscopic pre-selection (as in the Sloan Quasar Lens Search), or neural networks applied to photometric samples. These methods rely on cuts in morphology and colours, with the risk of losing many interesting objects due to scatter in their population properties, restrictive training sets, systematic uncertainties in catalog-based magnitudes, and survey-to-survey photometric variations. Here, we explore the performance of a Gaussian Mixture Model to separate point-like quasars, quasars with an extended host, and strongly lensed quasars using griz psf and model magnitudes and WISE W1, W2. The choice of optical magnitudes is due to their presence in all current and upcoming releases of wide-field surveys, whereas UV information is not always available. We then assess the contamination from blue galaxies and the role of additional features such as W3 magnitudes or psf-model terms as morphological information. As a demonstration, we conduct a search in a random 10% of the SDSS footprint, and we provide the catalog of the 43 SDSS object with the highest `lens' score in our selection that survive visual inspection, and are spectroscopically confirmed to host active nuclei. We inspect archival data and find images of 5/43 objects in the Hubble Legacy Archive, including 2 known lenses. The code and materials are available to facilitate follow-up.
2QDES Pilot：类星体聚类的光度和红移依赖性
影响因子：
4.8
作者：
Chehade B
通讯作者：
Chehade B