BeyondPlanck XIII. 强度前景采样、简并与先验
BeyondPlanck XIII. Intensity foreground sampling, degeneracies, and priors
AI总结：
本文介绍了BeyondPlanck框架中的强度前景算法与模型，通过联合采样、单极子确定及空间先验等技术改进了Commander成分分离，解决了有限数据下的前景参数简并问题，并指出异常微波辐射峰值频率是唯一具显著信噪比的谱参数。
摘要：
我们介绍了BeyondPlanck分析框架中使用的强度前景算法和模型。BeyondPlanck分析旨在将成分分离和仪器参数采样整合在一个全局框架内，从而在Planck低频仪器（LFI）数据分析中实现完整的端到端误差传播。鉴于BeyondPlanck分析的范围，成分分离过程中包含的数据集有限，导致了前景参数简并。为了正确约束银河系前景参数，我们通过添加一套算法技术改进了之前的Commander成分分离实现。这些算法旨在提高弱约束后验分布的稳定性和计算效率。这些技术包括：1）基于Miramare思想的前景谱参数和振幅联合采样；2）基于成分的单极子确定；3）谱参数和单极子联合采样；4）对成分振幅图应用信息性空间先验。我们发现，使用当前的BeyondPlanck数据集，唯一具有显著信噪比的谱参数是异常微波辐射分量的峰值频率，我们测得为$ν_{\mathrm{p}}=25.3\pm0.5$ GHz；所有其他参数必须通过外部先验进行约束。未来的工作将致力于将更多数据集（包括地图和时序数据）整合到该分析中，从而在仪器系统效应和天体物理简并两方面都以可控的方式逐步消除当前观测到的简并。届时，当前工作中使用的简单面向LFI的数据模型将需要进行推广，以兼顾更丰富的天体物理模型和额外的仪器效应。
英文摘要：
We present the intensity foreground algorithms and model employed within the BeyondPlanck analysis framework. The BeyondPlanck analysis is aimed at integrating component separation and instrumental parameter sampling within a global framework, leading to complete end-to-end error propagation in the $Planck$ Low Frequency Instrument (LFI) data analysis. Given the scope of the BeyondPlanck analysis, a limited set of data is included in the component separation process, leading to foreground parameter degeneracies. In order to properly constrain the Galactic foreground parameters, we improve upon the previous $\texttt{Commander}$ component separation implementation by adding a suite of algorithmic techniques. These algorithms are designed to improve the stability and computational efficiency for weakly constrained posterior distributions. These are: 1) joint foreground spectral parameter and amplitude sampling, building on ideas from Miramare; 2) component-based monopole determination; 3) joint spectral parameter and monopole sampling; and 4) application of informative spatial priors for component amplitude maps. We find that the only spectral parameter with a significant signal-to-noise ratio using the current BeyondPlanck data set is the peak frequency of the anomalous microwave emission component, for which we find $ν_{\mathrm{p}}=25.3\pm0.5$ GHz; all others must be constrained through external priors. Future works will be aimed at integrating many more data sets into this analysis, both map and time-ordered based, thereby gradually eliminating the currently observed degeneracies in a controlled manner with respect to both instrumental systematic effects and astrophysical degeneracies. When this happens, the simple LFI-oriented data model employed in the current work will need to be generalized to account for both a richer astrophysical model and additional instrumental effects.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
