The detectability of strong 21 centimetre forest absorbers from the diffuse intergalactic medium in late reionisation models
The detectability of strong 21 centimetre forest absorbers from the diffuse intergalactic medium in late reionisation models
复制标题
晚期再电离模型中来自弥漫星际介质的强 21 厘米森林吸收体的可探测性
DOI：
10.1093/mnras/stab1830
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发表时间：
2021
影响因子：
4.8
通讯作者：
Soltinský
中科院分区：
文献类型：
--
作者：
Soltinský
在红移5.3处再电离的晚期结束与观测到的Ly α森林传输的空间变化和Ly α辐射星系在扩展的Ly α吸收谷atz = 5.5附近的亏损相一致。在这个模型中，大型中性氢岛应该会持续存在于弥漫星系际介质（IGM）中，直到2006年。我们使用一种新的混合方法，结合高分辨率的宇宙学流体动力学模拟与辐射传输来预测在这些晚期再电离模型中，光学深度τ 21> 10 − 2的强21 cm森林吸收体从漫射IGM的入射。我们包括红移空间扭曲的影响，对模拟的21厘米森林光谱，和治疗高度不确定的加热预再电离IGM软X射线作为一个自由参数。对于一个模型，只有适度的IGM预热，这样的平均气体动力学温度在扩散IGM保持低于，我们发现，强大的21厘米森林吸收线应坚持untilz = 6。对于100个足够大的无线电背景源的样本，具有SKA 1低或可能LOFAR的21厘米森林吸收体（z 106）的零检测应该为高红移和温度下仍然很大程度上不受约束的软X射线背景提供信息下限预再电离IGM。
A late end to reionization at redshiftz≃ 5.3 is consistent with observed spatial variations in the Lyαforest transmission and the deficit of Lyαemitting galaxies around extended Lyαabsorption troughs atz= 5.5. In this model, large islands of neutral hydrogen should persist in the diffuse intergalactic medium (IGM) untilz≃ 6. We use a novel, hybrid approach that combines high-resolution cosmological hydrodynamical simulations with radiative transfer to predict the incidence of strong 21-cm forest absorbers with optical depthsτ21> 10−2from the diffuse IGM in these late reionization models. We include the effect of redshift space distortions on the simulated 21-cm forest spectra, and treat the highly uncertain heating of the pre-reionization IGM by soft X-rays as a free parameter. For a model with only modest IGM pre-heating, such that average gas kinetic temperatures in the diffuse IGM remain below, we find that strong 21-cm forest absorption lines should persist untilz= 6. For a sample of ∼10 sufficiently radio-loud background sources, a null-detection of 21-cm forest absorbers atz≃ 6 with SKA1-low or possibly LOFAR should provide an informative lower limit on the still largely unconstrained soft X-ray background at high redshift and the temperature of the pre-reionization IGM.