Mitigating foreground bias to the CMB lensing power spectrum for a CMB-HD survey
Mitigating foreground bias to the CMB lensing power spectrum for a CMB-HD survey
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DOI：
10.1103/physrevd.105.083516
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发表时间：
2021-12
影响因子：
5
通讯作者：
Dongwon Han;N. Sehgal
中科院分区：
文献类型：
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作者：
Dongwon Han;N. Sehgal
测量小尺度（k ~ 10 hMpc^-1）物质分布的一个很有希望的方法是利用宇宙微波背景辐射（CMB）的引力透镜效应。CMB-HD是一种拟议的高分辨率，低噪声毫米巡天，可以在如此小的尺度上测量CMB透镜自谱，从而可以区分冷暗物质（CDM）模型和旨在解决小尺度CDM问题的替代模型。然而，如果不加以处理，河外前景会使CMB透镜自谱产生偏差。我们提出了一个前景缓解策略，提供了一个路径，以减少从两个最主要的前景，热Sunyaev-Zel'dovich效应（tSZ）和宇宙红外背景（CIB）的偏见。考虑到我们的分析中包含的现实水平，我们发现，在[5000，20000]中的透镜多极范围L中，对于CMB-HD调查，单独的tSZ和单独的CIB分别使透镜自谱偏置0.6 sigma和1.1 sigma;结合这些前景产生仅1.3 sigma的偏置。包括这些前景，我们还发现，CMB-HD调查可以区分CDM模型和10^-22 eV FDM模型在5西格玛水平。这些结果提供了一个重要的步骤，证明前景污染可以充分减少，使一个强大的测量小尺度物质的功率谱与CMB-HD。
A promising way to measure the distribution of matter on small scales (k ~ 10 hMpc^-1) is to use gravitational lensing of the Cosmic Microwave Background (CMB). CMB-HD, a proposed high-resolution, low-noise millimeter survey over half the sky, can measure the CMB lensing auto spectrum on such small scales enabling measurements that can distinguish between a cold dark matter (CDM) model and alternative models designed to solve problems with CDM on small scales. However, extragalactic foregrounds can bias the CMB lensing auto spectrum if left untreated. We present a foreground mitigation strategy that provides a path to reduce the bias from two of the most dominant foregrounds, the thermal Sunyaev-Zel'dovich effect (tSZ) and the Cosmic Infrared Background (CIB). Given the level of realism included in our analysis, we find that the tSZ alone and the CIB alone bias the lensing auto spectrum by 0.6 sigma and 1.1 sigma respectively, in the lensing multipole range of L in [5000,20000] for a CMB-HD survey; combined these foregrounds yield a bias of only 1.3 sigma. Including these foregrounds, we also find that a CMB-HD survey can distinguish between a CDM model and a 10^-22 eV FDM model at the 5 sigma level. These results provide an important step in demonstrating that foreground contamination can be sufficiently reduced to enable a robust measurement of the small-scale matter power spectrum with CMB-HD.