J-comb: An image fusion algorithm to combine observations covering different spatial frequency ranges

作     者：Sihan Jiao Yuxin Lin Xiangyu Shui Jingwen Wu Zhiyuan Ren Di Li 

作者机构：National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of Chinese Academy of SciencesBeijing 100049China Centre for Astrochemical StudiesMax-Planck-Institut f¨ur Extraterrestrische PhysikGarching 85748Germany Astrophysics DepartmentMunich UniversityMunich 81679Germany NAOC-UKZN Computational Astrophysics CentreUniversity of KwaZulu-NatalDurban 4000South Africa 

出 版 物：《Science China(Physics,Mechanics & Astronomy)》 (中国科学：物理学、力学、天文学（英文版）)

年 卷 期：2022年第65卷第9期

页      面：138-156页

核心收录：

学科分类：07[理学] 08[工学] 080203[工学-机械设计及理论] 070401[理学-天体物理] 0802[工学-机械工程] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 11988101, 11725313, 11911530226, and 11403041) the Chinese Academy of Sciences (CAS) International Partnership Program (Grant No. 114A11KYSB20160008) 

主　　题：star formation molecular clouds image processing 

摘      要：Ground-based, high-resolution bolometric(sub)millimeter continuum mapping observations on spatially extended target sources are often subject to significant missing fluxes. This hampers accurate quantitative analyses. Missing flux can be recovered by fusing high-resolution images with observations that preserve extended structures. However, the commonly adopted image fusion approaches do not maintain the simplicity of the beam response function and do not try to elaborate the details of the yielded beam response functions. These make the comparison of the observations at multiple wavelengths not straightforward. We present a new algorithm, J-comb, which combines the high and low-resolution images linearly. By applying a taper function to the low-pass filtered image and combining it with a high-pass filtered image using proper weights, the beam response functions of our combined images are guaranteed to have near-Gaussian shapes. This makes it easy to convolve the observations at multiple wavelengths to share the same beam response functions. Moreover, we introduce a strategy to tackle the specific problem that the imaging at 850 μm from the present-date ground-based bolometric instrument and that taken with the Planck satellite do not overlap in the Fourier domain. We benchmarked our method against two other widely-used image combination algorithms, CASA-feather and MIRIAD-immerge, with mock observations of star-forming molecular clouds. We demonstrate that the performance of the J-comb algorithm is superior to those of the other two algorithms. We applied the J-comb algorithm to real observational data of the Orion A star-forming region. We successfully produced dust temperature and column density maps with ~10′′angular resolution, unveiling much greater details than the previous results. A py Thon code release of J-comb and implementation of the algorithm are available at https://***/Sihan Jiao/J-comb.