论文标题
光环职业分布的响应：光环模型中的新成分和对银河系偏见的影响
Responses of Halo Occupation Distributions: a new ingredient in the halo model & the impact on galaxy bias
论文作者
论文摘要
光环占用分布（HOD）模型描述了存在于不同光环中的星系数量，并使用Halo模型（HM）广泛用于银河系连接研究。在这里，我们介绍和研究HOD响应功能$ r_ \ Mathcal {o}^g $描述了HOD对长波长扰动的响应$ \ MATHCAL {O} $。线性星系偏差参数$ b_ \ Mathcal {o}^g $是$ b_ \ Mathcal {o}^h + r_ + r_ \ r_ \ nathcal {o}^g $的加权版本 文学。我们通过测量Illustristng模型的单独宇宙模拟中对三种类型的扰动的单独宇宙模拟中的$ r_ \ MATHCAL {O}^g $来研究了这一影响的影响：总物质扰动，$ \ MATHCAL {O} =Δ_M$; baryon-cdm补偿的等效性扰动，$ \ mathcal {o} =σ$;以及局部原始非高斯性的潜在扰动，$ \ MATHCAL {o} \ propto f _ {\ rm nl} ϕ $。我们的主要要点是，$ r_ \ Mathcal {o}^g $一般不可忽略不计，其大小应逐案估算。对于恒星质量选择的星系，响应$ r_Dcartion^g $和$r_σ^g $很大，并且在偏差参数的HM计算中不能忽略$ b_ϕ^g $和$b_σ^g $;这与使用星系约束通货膨胀有关。另一方面，我们没有检测到HOD响应$ r_1^g $对线性星系偏置$ B_1^g $的强烈影响。这些结果可以通过扰动对恒星到total质量关系的影响来解释。我们还研究了对气体分布偏见的影响，并找到类似的结论。我们表明，一个额外的参数描述了$ r_ \ Mathcal {o}^g $的总体幅度，恢复了测得的$ b_ \ Mathcal {o}^g $ well，这表明$ r_ \ Mathcal {o}^g $可以轻松地添加到HM/HOD研究中，以作为新的成分。
Halo occupation distribution (HOD) models describe the number of galaxies that reside in different haloes, and are widely used in galaxy-halo connection studies using the halo model (HM). Here, we introduce and study HOD response functions $R_\mathcal{O}^g$ that describe the response of the HODs to long-wavelength perturbations $\mathcal{O}$. The linear galaxy bias parameters $b_\mathcal{O}^g$ are a weighted version of $b_\mathcal{O}^h + R_\mathcal{O}^g$, where $b_\mathcal{O}^h$ is the halo bias, but the contribution from $R_\mathcal{O}^g$ is routinely ignored in the literature. We investigate the impact of this by measuring the $R_\mathcal{O}^g$ in separate universe simulations of the IllustrisTNG model for three types of perturbations: total matter perturbations, $\mathcal{O}=δ_m$; baryon-CDM compensated isocurvature perturbations, $\mathcal{O}=σ$; and potential perturbations with local primordial non-Gaussianity, $\mathcal{O}\propto f_{\rm NL}ϕ$. Our main takeaway message is that the $R_\mathcal{O}^g$ are not negligible in general and their size should be estimated on a case-by-case basis. For stellar-mass selected galaxies, the responses $R_ϕ^g$ and $R_σ^g$ are sizeable and cannot be neglected in HM calculations of the bias parameters $b_ϕ^g$ and $b_σ^g$; this is relevant to constrain inflation using galaxies. On the other hand, we do not detect a strong impact of the HOD response $R_1^g$ on the linear galaxy bias $b_1^g$. These results can be explained by the impact that the perturbations have on stellar-to-total-mass relations. We also look into the impact on the bias of the gas distribution and find similar conclusions. We show that a single extra parameter describing the overall amplitude of $R_\mathcal{O}^g$ recovers the measured $b_\mathcal{O}^g$ well, which indicates that $R_\mathcal{O}^g$ can be easily added to HM/HOD studies as a new ingredient.
