标题： 大尺度类星体邻近效应调查 显示英文标题

标题： Large-scale surveys of the quasar proximity effect

摘要： 高红移类星体的紫外线辐射在其光谱中导致中性氢吸收（莱曼-α森林）的局部缺失，这被称为近距效应。 已经使用数十到数百个类星体的小样本测量来限制紫外线背景辐射的总体强度，但到目前为止，尚未利用斯隆数字巡天和暗能量光谱巡天仪巡天等大尺度巡天的功率来更详细地研究紫外线背景。 我们开发了一个基于冷暗物质的晕模型，用于解释类星体近距效应，该模型在构建时考虑了类星体位于高密度区域这一事实。 我们在ASTRID宇宙学流体动力学模拟的类星体莱曼-α光谱上测试了该模型，该模拟包括类星体黑洞及其周围星际介质的一致形成。 将该模型拟合到单个类星体光谱上，我们限定了两个参数，r_eq（局部类星体辐射强度等于背景的半径）和类星体偏置b_q（与宿主晕质量相关）。 我们发现，从单个类星体光谱中可以以25-50%的统计不确定性无偏地恢复r_eq。 将这种拟合应用于例如DESI中的数百万光谱样本，将能够以高精度测量紫外线背景辐射强度及其随红移的变化。 我们使用另一个更大尺度、更低分辨率的模拟（Uchuu）来测试如此大规模的近距效应测量样本如何用于探测星际辐射场的空间波动。 我们发现，可以在100-1000 Mpc/h尺度上绘制紫外线辐射强度的大尺度结构并测量其功率谱。 这将使大尺度辐射场成为用于约束宇宙学和辐射源的数据集，与密度场一起使用。 显示英文摘要

摘要： The UV radiation from high redshift quasars causes a local deficit in the neutral hydrogen absorption (Lyman-alpha forest) in their spectra, known as the proximity effect. Measurements from small samples of tens to hundreds of quasars have been used to constrain the global intensity of the UV background radiation, but so far the power of large-scale surveys such as the Sloan Digital Sky Survey and the Dark Energy Spectroscopic Instrument (DESI) survey has not been used to investigate the UV background in more detail. We develop a CDM-based halo model of the quasar proximity effect, which accounts by construction for the fact that quasars reside in overdense regions. We test this model on quasar Lyman-alpha spectra from the ASTRID cosmological hydrodynamic simulation, which includes self-consistent formation of quasar black holes and the intergalactic medium surrounding them. Fitting the model to individual quasar spectra, we constrain two parameters, r_eq (the radius at which the local quasar radiation intensity equals the background), and the quasar bias b_q (related to host halo mass). We find that r_eq can be recovered in an unbiased fashion with a statistical uncertainty of 25-50% from a single quasar spectrum. Applying such fitting to samples of millions of spectra from e.g., DESI would allow measurement of the UVBG intensity and its evolution with redshift with high precision. We use another, larger-scale, lower resolution simulation (Uchuu) to test how such a large sample of proximity effect measurements could be used to probe the spatial fluctuations in the intergalactic radiation field. We find that the large-scale structure of the UV radiation intensity could be mapped and its power spectrum measured on 100-1000 Mpc/h scales. This could allow the large-scale radiation field to join the density field as a dataset for constraining cosmology and the sources of radiation.