Isotropic wavelets: a powerful tool to extract point sources from cosmic microwave background maps
Isotropic wavelets: a powerful tool to extract point sources from cosmic microwave background maps
复制标题
各向同性小波：从宇宙微波背景图中提取点源的强大工具
DOI：
--
复制
发表时间：
1999
期刊：
影响因子：
--
通讯作者：
F. Argüeso
中科院分区：
文献类型：
--
作者：
L. Cayón;J. L. Sanz;R. B. Barreiro;R. B. Barreiro;E. Martinez;P. Vielva;P. Vielva;L. Toffolatti;J. Silk;J. M. Diego;J. M. Diego;F. Argüeso
本文的目的是介绍使用各向同性小波探测和确定宇宙微波背景图（CMB）中出现的点源通量。最适合检测高斯波束滤波点源的小波是“墨西哥帽”。在点源的存在下获得的小波系数的解析表达式，并在检测和通量估计方法中使用。为了说明，该方法应用于由CMB（100 GHz）和尘埃（857 GHz）主导的两个模拟（假设普朗克使命特征），因为这将是普朗克通道中分别在低频和高频占主导地位的两个信号。我们能够在857 GHz处探测到1.58 Jy以上的亮源（占所有辐射源的82%）和100千兆赫0.36焦耳以上（全部的100%），通量估计的误差低于25%。这种方法的主要优点是不必对下伏场作任何假设，即关于地图中存在的信号加噪声的性质和属性。在Tegmark和Oliveira-Costa提出的检测方法中，情况并非如此。这两种方法进行比较，产生类似的结果。
It is the aim of this paper to introduce the use of isotropic wavelets to detect and determine the flux of point sources appearing in cosmic microwave background (CMB) maps. The most suitable wavelet to detect point sources filtered with a Gaussian beam is the ‘Mexican Hat’. An analytical expression of the wavelet coefficient obtained in the presence of a point source is provided and used in the detection and flux estimation methods presented. For illustration the method is applied to two simulations (assuming Planck mission characteristics) dominated by CMB (100 GHz) and dust (857 GHz), as these will be the two signals dominating at low and high frequencies respectively in the Planck channels. We are able to detect bright sources above 1.58 Jy at 857 GHz (82 per cent of all sources) and above 0.36 Jy at 100 GHz (100 per cent of all), with errors in the flux estimation below 25 per cent. The main advantage of this method is that nothing has to be assumed about the underlying field, i.e. about the nature and properties of the signal plus noise present in the maps. This is not the case in the detection method presented by Tegmark & Oliveira-Costa. Both methods are compared, producing similar results.