论文标题
非高斯性对使用21 cm功率谱测量的电离参数预测时期的影响
The impact of non-Gaussianity on the Epoch of Reionization parameter forecast using 21-cm power spectrum measurements
论文作者
论文摘要
电离时期（EOR）21-CM信号的测量具有约束电离模型的潜力。在本文中，我们考虑了一个带有三个天体物理参数的电源化模型（1）最小光环质量可以托管电离源，$ m _ {\ rm min} $，（2）电离光子的电离光子数量逃到了halo中的IgM中，halo，$ n _ _ _ _ {\ rm rmiion phot phot phot phot phot phot phot phot phot phot phot phot。 Igm，$ r _ {\ rm Mfp} $。我们预测可以使用即将到来的SKA-LOW对21-CM功率谱（PS）的未来观察结果来测量这些参数的准确性。与早期作品不同，我们说明了固有的EOR 21-CM信号的非高斯性。仅考虑宇宙差异并假设前景被完全删除，我们发现非高斯性将参数的$1σ$错误椭圆形的体积增加了$ 133 $相对于高斯预测，而方向也不同。当观测时间分别为$ 1024 $和$ 10000 $小时的错误椭圆形量的比例为$ 1.65 $和$ 2.67 $，当时所有前景楔形内的所有$ \ Mathbf {K} $模式都被排除在外。由于排除了前景楔块，并以1024美元的$ $小时为单位，1D边缘化的错误为$（ΔM_ {\ rm min}/m _ {\ rm min}，Δn_{\ rm ion}/n _ _ {\ rm ion}/n _ _ {\ rm ion}，\ rm ion}，Δr mfp}）=（6.54，2.71，7.75）\ times 10^{ - 2} $，分别为$ 2 \％$，$ 5 \％$和$ 23 \％$ $ \％$ $比相应的高斯预测大。对于较长的观察，非高斯性的影响增加了，对于$ r _ {\ rm mfp} $，尤其重要。
Measurements of the Epoch of Reionization (EoR) 21-cm signal hold the potential to constrain models of reionization. In this paper we consider a reionization model with three astrophysical parameters namely (1) the minimum halo mass which can host ionizing sources, $M_{\rm min}$, (2) the number of ionizing photons escaping into the IGM per baryon within the halo, $N_{\rm ion}$ and (3) the mean free path of the ionizing photons within the IGM, $R_{\rm mfp}$. We predict the accuracy with which these parameters can be measured from future observations of the 21-cm power spectrum (PS) using the upcoming SKA-Low. Unlike several earlier works, we account for the non-Gaussianity of the inherent EoR 21-cm signal. Considering cosmic variance only and assuming that foregrounds are completely removed, we find that non-Gaussianity increases the volume of the $1 σ$ error ellipsoid of the parameters by a factor of $133$ relative to the Gaussian predictions, the orientation is also different. The ratio of the volume of error ellipsoids is $1.65$ and $2.67$ for observation times of $1024$ and $10000$ hours respectively, when all the $\mathbf{k}$ modes within the foreground wedge are excluded. With foreground wedge excluded and for $1024$ hours, the 1D marginalized errors are $(ΔM_{\rm min}/M_{\rm min},ΔN_{\rm ion}/N_{\rm ion},ΔR_{\rm mfp}/R_{\rm mfp})=(6.54, 2.71, 7.75) \times 10^{-2}$ which are respectively $2 \%$, $5 \%$ and $23 \%$ larger than the respective Gaussian predictions. The impact of non-Gaussianity increases for longer observations, and it is particularly important for $R_{\rm mfp}$.
