Mitigating the effect of 1/ f noise on the detection of the H i intensity mapping power spectrum from single-dish measurements
Mitigating the effect of 1/ f noise on the detection of the H i intensity mapping power spectrum from single-dish measurements
复制标题
减轻 1/ f 噪声对单碟测量中 Hi 强度映射功率谱检测的影响
DOI：
10.1093/mnras/stad3457
复制
发表时间：
2024
影响因子：
4.8
通讯作者：
Irfan M
中科院分区：
文献类型：
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作者：
Irfan M
我们提出并比较了几种方法来减轻MeerKAT大面积天气调查（MeerKLASS）的h强度制图组件中的时间相关（1/f）噪声。通过模拟扫描策略、h信号、前景辐射、白噪声和相关噪声，我们评估了各种数据处理管道恢复h亮度温度波动功率谱的能力。我们使用MeerKAT试点数据来评估MeerKLASS调查预期的1/f噪声水平，并使用这些测量结果为我们的模拟创建真实的时间相关噪声水平。我们发现试点数据中的时间相关噪声分量比白噪声水平高10到20倍。在确定MeerKAT 1/f噪声在所有频率通道上部分相关后，我们采用奇异值分解（SVD）作为去除1/f噪声和银河系前景的技术，但发现过度清洗会导致大尺度（角和径向）的h功率去除；对于3模式SVD，其功率损失为40%。我们比较了使用全噪声协方差（即包括1/f分量）加权的地图制作的影响，而不是简单的未加权分帧，发现包括时间相关的噪声信息可将1/f噪声增加的多余功率减少多达30%。
We present and compare several methods to mitigate time-correlated (1/f) noise within theH iintensity mapping component of the MeerKAT Large Area Synoptic Survey (MeerKLASS). By simulating scan strategies, theH isignal, foreground emissions, white and correlated noise, we assess the ability of various data-processing pipelines to recover the power spectrum ofH ibrightness temperature fluctuations. We use MeerKAT pilot data to assess the level of 1/fnoise expected for the MeerKLASS survey and use these measurements to create realistic levels of time-correlated noise for our simulations. We find the time-correlated noise component within the pilot data to be between 10 and 20 times higher than the white noise level at the scale of. Having determined that the MeerKAT 1/fnoise is partially correlated across all the frequency channels, we employ Singular Value Decomposition (SVD) as a technique to remove both the 1/fnoise and Galactic foregrounds but find that over-cleaning results in the removal ofH ipower at large (angular and radial) scales; a power loss of 40 per cent is seen for a 3-mode SVD clean at the scale of. We compare the impact of map-making using weighting by the full noise covariance (i.e. including a 1/fcomponent), as opposed to just a simple unweighted binning, finding that including the time-correlated noise information reduces the excess power added by 1/fnoise by up to 30 per cent.