论文标题
红外中学调查。 ix。发现两个新的$ z \ sim6 $ quasars和空间密度降低至$ m_ {1450} \ sim-23.5 $ mag
The Infrared Medium-deep Survey. IX. Discovery of Two New $z\sim6$ Quasars and Space Density down to $M_{1450}\sim-23.5$ mag
论文作者
论文摘要
我们使用IMS近红外图像和加拿大 - 弗朗西·弗朗西 - 弗朗西·赫瓦伊望远镜传统调查（CFHTLS）光学图像的组合，介绍了红外中学调查（IMS）$ z \ sim6 $ quasar调查的结果。传统的颜色选择方法导致25种超过$ 86 $ deg $^{2} $的候选者。我们介绍了使用高红移准和后期型星模型介绍了校正后的Akaike信息标准（AICC），以有效地优先考虑候选人。在颜色选择的候选人中，七名合理的候选人终于通过了AICC选择，其中三个是$ z \ sim6 $的众所周知的类星体。进行了其余四名候选人的后续光谱观察结果，我们确认四分之二是$ z \ sim6 $ quasars。使用此完整的样本，我们以$ z \ sim6 $的价格重新访问了类星体空间密度，降低到$ m_ {1450} \ sim-23.5 $ mag。我们的结果支持了类星体的紫外线电离发射率的亮度低的类星体空间密度，有利于类星体对宇宙电离的较小贡献。
We present the result of the Infrared Medium-deep Survey (IMS) $z\sim6$ quasar survey, using the combination of the IMS near-infrared images and the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) optical images. The traditional color-selection method results in 25 quasar candidates over $86$ deg$^{2}$. We introduce the corrected Akaike Information Criterion (AICc) with the high-redshift quasar and late-type star models to prioritize the candidates efficiently. Among the color-selected candidates, seven plausible candidates finally passed the AICc selection of which three are known quasars at $z\sim6$. The follow-up spectroscopic observations for the remaining four candidates were carried out, and we confirmed that two out of four are $z\sim6$ quasars. With this complete sample, we revisited the quasar space density at $z\sim6$ down to $M_{1450}\sim-23.5$ mag. Our result supports the low quasar space density at the luminosity where the quasar's ultraviolet ionizing emissivity peaks, favoring a minor contribution of quasars to the cosmic reionization.
