In this article, the temperature–density relation of the intergalactic medium was studied in the region 1.6 ≤ z < 2.0 divided into two bins. For this purpose, the Ly α forest decomposition into individual absorption profiles was used for the study of 35 publicly available quasar spectra obtained by the Ultraviolet and Visual Echelle Spectrograph (UVES) on the Very Large Telescope (ESO) and by the High Resolution Echelle Spectrometer (HIRES) on the Keck Telescope. For the determination of the thermal state sensitive cut-off position in the $b - N_{\rm{H}\, \small {I}}$ distribution, the iterative fitting procedure was adopted. The measurements were calibrated using mock Ly α forest data generated by 23 hydrodynamical simulations with different thermal histories. The value of the temperature at mean density corresponds to the decreasing trend predicted by various models at the lower redshifts. In the case of power-law index, determined values are close to 1.6, which is expected after all reionization events in various models assuming the balance of photoheating with adiabatic cooling.

中文翻译：

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接近Lyα森林光学极限的星系际介质的热态

本文研究了 1.6 ≤ z < 区域内星系际介质的温度-密度关系。2.0分为两个bin。为此，将 Ly α 森林分解为单个吸收剖面用于研究由超大望远镜 (ESO) 上的紫外和视觉阶梯光谱仪 (UVES) 和高分辨率阶梯光谱仪获得的 35 个公开可用的类星体光谱（雇佣）在凯克望远镜上。为了确定$b - N_{\rm{H}\, \small {I}}$ 分布中的热态敏感截止位置，采用了迭代拟合程序。使用由具有不同热历史的 23 次流体动力学模拟生成的模拟 Ly α 森林数据校准测量值。平均密度处的温度值对应于各种模型在较低红移处预测的下降趋势。在幂律指数的情况下，确定的值接近 1.6，这是在假设光热与绝热冷却平衡的各种模型中的所有再电离事件之后预期的。