A measurement of the Ly-β forest power spectrum and its cross with the Ly-α forest in X-Shooter XQ-100
A measurement of the Ly-β forest power spectrum and its cross with the Ly-α forest in X-Shooter XQ-100
复制标题
Ly-β 森林功率谱的测量及其与 X-Shooter XQ-100 中 Ly-α 森林的交叉
DOI：
10.1093/mnras/stab3017
复制
发表时间：
2022
影响因子：
4.8
通讯作者：
McQuinn, Matthew
中科院分区：
文献类型：
--
作者：
Wilson, Bayu;Iršič, Vid;McQuinn, Matthew
Ly α森林是大尺度结构探测器，我们似乎对最高波数进行了建模控制。这使得Ly α森林在限制暗物质的热度/热度和再电离过程的时间方面引起了极大的兴趣。然而，标准的统计量Ly α森林功率谱不能强有力地约束星系际介质（IGM）的温度-密度关系，这进一步限制了其他高波数敏感参数的约束效果。为了打破这些简并，我们使用VLT/X-Shooter XQ-100 Legacy Survey中的100个z = 3.5-4.5的类星体测量了Ly β森林的功率谱及其与同时期Ly α森林的互相关，这是由于Ly β跃迁的吸收截面较小，使得它对相对于Ly α跃迁的密度更高的密度敏感。我们从IGM温度-密度关系的测量中得出的推论似乎与最近严格的低红移Ly α森林约束一致。我们用Ly α-Ly β互相关发现的T = 3.4-4.7的趋势表明温度-密度关系的斜率随着红移的减小而变平。这是正在进行的氢再电离的预期趋势，并且在氢再电离完成后有足够的时间达到渐进的温度-密度斜率。此外，我们的测量提供了解释Ly α森林的IGM模型的一致性检查，交叉相关性不受两个森林之间不相关的系统学的影响，例如金属线污染。
The Ly α forest is the large-scale structure probe for which we appear to have modelling control to the highest wavenumbers. This makes the Ly α forest of great interest for constraining the warmness/fuzziness of dark matter and the timing of reionization processes. However, the standard statistic, the Ly α forest power spectrum, is unable to strongly constrain the intergalactic medium (IGM) temperature–density relation, and this inability further limits how well other high-wavenumber-sensitive parameters can be constrained. With the aim of breaking these degeneracies, we measure the power spectrum of the Ly β forest and its cross-correlation with the coeval Ly α forest using the 100 spectra ofz= 3.5–4.5 quasars in the VLT/X-Shooter XQ-100 Legacy Survey, motivated by the Ly β transition’s smaller absorption cross-section that makes it sensitive to somewhat higher densities relative to the Ly α transition. Our inferences from this measurement for the IGM temperature–density relation appear to latch consistently on to the recent tight lower redshift Ly α forest constraints. Thez= 3.4–4.7 trends we find using the Ly α–Ly β cross-correlation show a flattening of the slope of the temperature–density relation with decreasing redshift. This is the trend anticipated from ongoing Heiireionization and there being sufficient time to reach the asymptotic temperature–density slope after hydrogen reionization completes. Furthermore, our measurements provide a consistency check on IGM models that explain the Ly α forest, with the cross-correlation being immune to systematics that are uncorrelated between the two forests, such as metal line contamination.