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Pré-Publication, Document De Travail Année : 2024

Forecast of foreground cleaning strategies for AliCPT-1

Junzhou Zhang
  • Fonction : Auteur
Shamik Ghosh
  • Fonction : Auteur
Jiazheng Dou
  • Fonction : Auteur
Yang Liu
  • Fonction : Auteur
Siyu Li
  • Fonction : Auteur
Jiming Chen
  • Fonction : Auteur
Jiaxin Wang
  • Fonction : Auteur
Zhaoxuan Zhang
  • Fonction : Auteur
Mathieu Remazeilles
  • Fonction : Auteur
Chang Feng
  • Fonction : Auteur
Bin Hu
  • Fonction : Auteur
Hao Liu
  • Fonction : Auteur
Larissa Santos
  • Fonction : Auteur
Pengjie Zhang
  • Fonction : Auteur
Wen Zhao
  • Fonction : Auteur
Le Zhang
  • Fonction : Auteur
Zhi-Qi Huang
  • Fonction : Auteur
Hong Li
  • Fonction : Auteur
Chao-Lin Kuo
  • Fonction : Auteur
Xinmin Zhang
  • Fonction : Auteur

Résumé

We report the test results of several independent foreground-cleaning pipelines used in the Ali CMB Polarization Telescope experiment (AliCPT-1), a high-altitude CMB imager in the Northern hemisphere with thousands of detectors dedicated to the search for a primordial CMB polarization $B$-mode signature. Based on simulated data from 4 detector modules and a single season of observation, which we refer to as DC1 data, we employ different and independent pipelines to examine the robustness and effectiveness of the estimates on foreground parameters and the primordial $B$-mode detection. The foreground-cleaning strategies used in the pipelines include the parametric method of template fitting (TF) and the non-parametric methods of the constrained internal linear combination (cILC), the analytical blind separation (ABS), and the generalized least squares (GLS). We examine the impact of possible foreground residuals on the estimate of the CMB tensor-to-scalar ratio ($r$) for each pipeline by changing the contamination components in the simulated maps and varying the foreground models and sky patches for various tests. According to the DC1 data with the simulation input value $r_{\rm true}=0.023$, the foreground residual contamination levels in the TF/ABS/cILC/GLS pipelines are well within the corresponding statistical errors at the $2\sigma$ level. For a selected patch with relatively stronger foreground contamination, all of the proposed pipelines perform robustly in testing. Furthermore, by utilizing the tension estimator, which helps identify significant residual foreground contamination in the detection of the primordial $B$-mode signal by quantifying the discrepancy between various $r$ measurements, we conclude that the presence of small foreground residuals does not lead to any significant inconsistency in the estimation of $r$.

Dates et versions

hal-04456587 , version 1 (14-02-2024)

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Citer

Junzhou Zhang, Shamik Ghosh, Jiazheng Dou, Yang Liu, Siyu Li, et al.. Forecast of foreground cleaning strategies for AliCPT-1. 2024. ⟨hal-04456587⟩

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