An ultradeep submillimetre map: beneath the SCUBA confusion limit with lensing and robust source extraction
An ultradeep submillimetre map: beneath the SCUBA confusion limit with lensing and robust source extraction
复制标题
超深亚毫米地图：通过透镜和强大的源提取，低于水肺混淆极限
DOI：
10.1111/j.1365-2966.2006.10138.x
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发表时间：
2006
影响因子：
4.8
通讯作者：
J. A. Peacock
中科院分区：
文献类型：
--
作者：
K. Knudsen;V. Barnard;P. Werf;P. Vielva;J. Kneib;A. Blain;R. B. Barreiro;R. Ivison;I. Smail;J. A. Peacock
从具有结构化背景的地图中提取低信噪比（S/N）源是一项非常重要的任务，在研究亚毫米（submm）数计数的微弱端变得非常重要。本文利用墨西哥帽小波（MHW）这一各向同性小波技术，研究了亚毫米波共用户辐射计阵列（SCUBA）的亚毫米波抖动图的源提取。作为案例研究，我们使用了星系团Abell 2218 （A2218）的大型（11.8 arcmin 2）抖动图，其rms为850 μm，灵敏度为0.6-1 mJy。仿真结果表明，MHW是一种强大的工具，可以可靠地从SCUBA抖动图中提取低信噪比源，并且在A2218 850-μm图像中检测到9个低信噪比源。其中三个源被确定为单个背景源的图像，无透镜通量为0.8 mJy。此外，两个单像光源也具有<2 mJy的未透镜通量，低于空白场混淆极限。在这张超深图中，探测到的单个源几乎可以分辨850 μm的所有河外背景光，而深度数据允许在850 μm处设置44个源arcmin -2至0.2 mJy的上限。
Extracting sources with low signal-to-noise ratio (S/N) from maps with structured background is a non-trivial task which has become important in studying the faint end of the submillimetre (submm) number counts. In this paper, we study the source extraction from submm jiggle-maps from the Submillimetre Common-User Bolometer Array (SCUBA) using the Mexican hat wavelet (MHW), an isotropic wavelet technique. As a case study, we use a large (11.8-arcmin 2 ) jiggle-map of the galaxy cluster Abell 2218 (A2218), with a 850-μm la rms sensitivity of 0.6-1 mJy. We show via simulations that MHW is a powerful tool for the reliable extraction of low-S/N sources from the SCUBA jiggle-maps and nine sources are detected in the A2218 850-μm image. Three of these sources are identified as images of a single background source with an unlensed flux of 0.8 mJy. Further, two single-imaged sources also have unlensed fluxes <2 mJy, below the blank-field confusion limit. In this ultradeep map, the individual sources detected resolve nearly all of the extragalactic background light at 850 μm, and the deep data allow to put an upper limit of 44 sources arcmin -2 to 0.2 mJy at 850 μm.