来自HI强度映射和星系巡天的交叉双谱约束
Cross-Bispectrum Constraints from HI Intensity Mapping and Galaxy Surveys
- University of KwaZulu-Natal（夸祖鲁-纳塔尔大学）
- University of Witwatersrand（威特沃特斯兰德大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究通过HI强度映射与光学巡天的交叉双谱，恢复被前景扣除的径向模式，打破简并，显著提升宇宙学参数约束精度。
AI中文摘要：
未来的中性氢（HI）强度映射（IM）和光学巡天以前所未有的体积探测大尺度结构，为宇宙学模型提供强有力的约束。我们研究了HI IM场与来自光学巡天的星系密度和宇宙剪切场之间的互相关。通过构建HI-HI-星系和HI-HI-剪切交叉双谱，我们恢复了对长波径向模式的敏感性，这些模式在HI图中通常因前景扣除而被移除，并评估了它们在HIRAX和Rubin-LSST中的可探测性。结合这些探针打破了红移相关量中的简并性，包括$f$-$\sigma_8$简并。在我们考虑的六个红移区间中，我们对$f$的约束范围为$0.74\\%$至$9.8\\%$，对$\sigma_8$的约束范围为$0.073\\%$至$3.5\\%$。我们对一阶和二阶HI偏置参数的约束范围为：$b_{\rm HI}^{(1)}$从$0.42\\%$到$5.6\\%$，$b_{\rm HI}^{(2)}$从$2.0\\%$到$29\\%$，而星系偏置约束范围为$b_{\rm gal}$从$2.6\\%$到$11\\%$。HI-HI-星系密度交叉双谱测量使我们能够约束HI与恒星之间随机互相关系数的线性尺度依赖模型，$r_{{\rm HI \\,HI\\,}\delta_g} = r_0 + r_1 k,$ 其断裂尺度为$0.14\\,\mbox{Mpc}^{-1}.$ 我们获得的$r_0$约束范围为$3.8\\%$至$13.5\\%$，$r_1$约束范围为$7.5\\%$至$19.9\\%$。对于宇宙学，添加交叉双谱增强了Lambda CDM约束，特别是通过HI-HI-剪切交叉双谱。对于$w_0\\, w_a$CDM模型，仅功率谱的$w_0$和$w_a$约束（包括Planck先验）从$(\sigma_{w_0},\sigma_{w_a})=(0.036,0.15)$和$(0.032,0.12)$分别改善到$(\sigma_{w_0},\sigma_{w_a})=(0.014,0.057)$和$(0.015,0.059)$，当分别添加HI-HI-星系和HI-HI-剪切交叉双谱时。
英文摘要：
Future neutral hydrogen (HI) intensity mapping (IM) and optical surveys probe large-scale structure over unprecedented volumes, offering powerful constraints on cosmological models. We study the cross-correlation between the HI IM field and the galaxy density and cosmic shear fields from optical surveys. By formulating the HI-HI-galaxy and HI-HI-shear cross-bispectra, we recover sensitivity to long-wavelength radial modes otherwise removed by foreground subtraction in HI maps, evaluating their detectability for HIRAX and Rubin-LSST. Combining the probes breaks degeneracies in redshift-dependent quantities, including the $f$-$σ_8$ degeneracy. Our constraints range from $0.74\%$ to $9.8\%$ on $f$ and $0.073\%$ to $3.5\%$ on $σ_8$ across the six redshift bins that we consider. Our constraints on the first- and second-order HI bias parameters range from $0.42\%$ to $5.6\%$ on $b_{\rm HI}^{(1)}$ and from $2.0\%$ to $29\%$ on $b_{\rm HI}^{(2)}$, while the galaxy bias constraints range from $2.6\%$ to $11\%$ on $b_{\rm gal}.$ The HI-HI-galaxy density cross-bispectrum measurement allows us to constrain a linear scale-dependent model for the stochastic cross-correlation coefficient between HI and stars, $r_{{\rm HI \,HI\,}δ_g} = r_0 + r_1 k,$ with a break scale of $0.14\,\mbox{Mpc}^{-1}.$ We obtain $r_0$ constraints that range from $3.8\%$ to $13.5\%$ and $r_1$ constraints that range from $7.5\%$ to $19.9\%$. For cosmology, adding cross-bispectra enhances Lambda CDM constraints, notably via the HI-HI-shear cross-bispectrum. For the $w_0\, w_a$CDM model, the power-spectrum-only constraints on $w_0$ and $w_a,$ including Planck priors, improve from $(σ_{w_0},σ_{w_a})=(0.036,0.15)$ and $(0.032,0.12)$ to $(σ_{w_0},σ_{w_a})=(0.014,0.057)$ and $(0.015,0.059)$ when adding the HI-HI-galaxy and HI-HI-shear cross-bispectra, respectively.
