论文标题
部分可观测时空混沌系统的无模型预测
Cosmological constraints from the power spectrum and bispectrum of 21cm intensity maps
论文作者
论文摘要
中性氢的21厘米发射是对宇宙中物质分布的潜在探针。 SKAO和HIRAX实验将在未来几年内对这一线强度进行宇宙学调查，这是对即将进行的Galaxy Surveys的补充。我们介绍了21cm功率谱和双光谱的组合对宇宙学约束的第一个预测。计算Fisher的预测，以这些调查对宇宙学参数，BAO距离功能和生长函数的约束能力进行计算。我们还估计动态暗能量和修饰的重力的约束功率。最后，我们研究了对21cm聚类偏置的约束，最高为二阶。我们考虑对望远镜束，仪器噪声，前景避免，阿尔科克 - 帕辛斯基效应和相关器建模中理论错误的影响。 Hirax在$λ$ CDM参数上添加Planck先验并在滋扰参数上边缘化，Skao的精度略低。修改后的重力参数$γ$被限制为1％（HIRAX）和5％（SKAO）。对于暗能量参数$ W_0，W_A $，HIRAX可提供百分比的精度，而SKAO约束较弱。 Hirax在BAO距离功能上达到了次级精度$ d_a，h $，而Skao以$ 0.6 \ Lessim Z \ Lessim 1 $ 1 $的价格达到1-2％。对于整个红移范围，增长率$ f $在几％的水平上受到限制，Skao的$ 0.6 \ Lessim z \ Lessim 1 $。不同的性能主要是因为HIRAX是一种填充的入口仪，用于BAO测量值，而SKAO并未针对干涉仪宇宙学进行优化，并且在单次模式下运行较好，在单端模式下，远程横梁限制了对较小的尺度的访问。
The 21cm emission of neutral hydrogen is a potential probe of the matter distribution in the Universe after reionisation. Cosmological surveys of this line intensity will be conducted in the coming years by the SKAO and HIRAX experiments, complementary to upcoming galaxy surveys. We present the first forecasts of the cosmological constraints from the combination of the 21cm power spectrum and bispectrum. Fisher forecasts are computed for the constraining power of these surveys on cosmological parameters, the BAO distance functions and the growth function. We also estimate the constraining power on dynamical dark energy and modified gravity. Finally we investigate the constraints on the 21cm clustering bias, up to second order. We consider the effects on the 21cm correlators of the telescope beam, instrumental noise, foreground avoidance, the Alcock-Paczynski effect and theoretical errors in the modelling of the correlators. Adding Planck priors, and marginalising over nuisance parameters, HIRAX achieves sub-percent precision on the $Λ$CDM parameters, with SKAO delivering slightly lower precision. The modified gravity parameter $γ$ is constrained at 1% (HIRAX) and 5% (SKAO). For the dark energy parameters $w_0,w_a$, HIRAX delivers percent-level precision while SKAO constraints are weaker. HIRAX achieves sub-percent precision on the BAO distance functions $D_A,H$, while SKAO reaches 1-2% for $0.6\lesssim z\lesssim 1$. The growth rate $f$ is constrained at a few-percent level for the whole redshift range of HIRAX and for $0.6\lesssim z\lesssim 1$ by SKAO. The different performances arise mainly since HIRAX is a packed inteferometer that is optimised for BAO measurements, while SKAO is not optimised for interferometer cosmology and operates better in single-dish mode, where the telescope beam limits access to the smaller scales that are covered by an interferometer.
