论文标题
我们实际上可以使用依赖比例依赖性偏差效果来限制$ f _ {\ rm nl} $吗？使用Boss DR12 Galaxy Power Spectrum的银河偏置不确定性的影响的说明
Can we actually constrain $f_{\rm NL}$ using the scale-dependent bias effect? An illustration of the impact of galaxy bias uncertainties using the BOSS DR12 galaxy power spectrum
论文作者
论文摘要
依赖比例的偏差对银河系功率谱的效果是对局部原始非高斯性（PNG）参数$ f _ {\ rm nl} $的非常有前途的探针，但是效果的幅度与$ f _ {\ rm nl} b_其他$ b_ demgaing，$ f _ {\ rm rm nl} b_ demax $ bias ban is line can and ancal and ancal and。我们对$ b_ϕ $的知识目前非常有限，但是几乎所有现有的$ f _ {\ rm nl} $约束和预测对其具有精确的知识。在这里，我们使用Boss DR12 Galaxy Power Spectrum来说明我们对$ b_ϕ $的不确定知识当前如何使用给定的统计精度$σ_{f _ {\ rm nl}} $限制$ f _ {\ rm nl} $。假设$ b_ϕ $和线性密度偏见$ b_1 $之间的关系有不同的固定选择，我们发现$σ_{f _ {\ rm nl}} $可能会随着一个数量级的差异而变化。我们最强的界限是$ f _ {\ rm nl} = 16 \ pm 16 \（1σ）$，而松散为$ f _ {\ rm nl} = 230 \ pm 226 \（1σ）$对于同一boss数据。 $ b_ϕ $的影响特别明显，因为它可以接近零。我们还展示了在$ b_ϕ $上的边缘化如何使用广泛的先验不保守，实际上导致通过参数空间投影效应造成偏见的约束。 Independently of galaxy bias assumptions, the scale-dependent bias effect can only be used to detect $f_{\rm NL} \neq 0$ by constraining the product $f_{\rm NL}b_ϕ$, but the error bar $σ_{f_{\rm NL}}$ remains undetermined and the results cannot be compared with the CMB;我们发现$ f _ {\ rm nl} b_ϕ \ neq 0 $，$1.6σ$ aintivance。我们还评论为什么这些问题对于使用Galaxy Biseptrum进行分析很重要。我们的结果强烈激励基于仿真的研究计划，旨在为$ b_qual参数提供强大的理论先验，没有galaxy数据，我们可能永远无法竞争地限制$ f _ {\ rm nl} $。
The scale-dependent bias effect on the galaxy power spectrum is a very promising probe of the local primordial non-Gaussianity (PNG) parameter $f_{\rm NL}$, but the amplitude of the effect is proportional to $f_{\rm NL}b_ϕ$, where $b_ϕ$ is the linear PNG galaxy bias parameter. Our knowledge of $b_ϕ$ is currently very limited, yet nearly all existing $f_{\rm NL}$ constraints and forecasts assume precise knowledge for it. Here, we use the BOSS DR12 galaxy power spectrum to illustrate how our uncertain knowledge of $b_ϕ$ currently prevents us from constraining $f_{\rm NL}$ with a given statistical precision $σ_{f_{\rm NL}}$. Assuming different fixed choices for the relation between $b_ϕ$ and the linear density bias $b_1$, we find that $σ_{f_{\rm NL}}$ can vary by as much as an order of magnitude. Our strongest bound is $f_{\rm NL} = 16 \pm 16\ (1σ)$, while the loosest is $f_{\rm NL} = 230 \pm 226\ (1σ)$ for the same BOSS data. The impact of $b_ϕ$ can be especially pronounced because it can be close to zero. We also show how marginalizing over $b_ϕ$ with wide priors is not conservative, and leads in fact to biased constraints through parameter space projection effects. Independently of galaxy bias assumptions, the scale-dependent bias effect can only be used to detect $f_{\rm NL} \neq 0$ by constraining the product $f_{\rm NL}b_ϕ$, but the error bar $σ_{f_{\rm NL}}$ remains undetermined and the results cannot be compared with the CMB; we find $f_{\rm NL}b_ϕ \neq 0$ with $1.6σ$ significance. We also comment on why these issues are important for analyses with the galaxy bispectrum. Our results strongly motivate simulation-based research programs aimed at robust theoretical priors for the $b_ϕ$ parameter, without which we may never be able to competitively constrain $f_{\rm NL}$ using galaxy data.
