An improved method for 21-cm foreground removal |
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| Authors: | Adrian Liu Max Tegmark Judd Bowman † Jacqueline Hewitt Matias Zaldarriaga |
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| Institution: | Department of Physics and MIT Kavli Institute, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139, USA;Department of Physics, California Institute of Technology, Pasadena, CA 91125, USA;Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA;Jefferson Laboratory of Physics, Harvard University, Cambridge, MA 02138, USA |
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| Abstract: | 21-cm tomography is expected to be difficult in part because of serious foreground contamination. Previous studies have found that line-of-sight approaches are capable of cleaning foregrounds to an acceptable level on large spatial scales, but not on small spatial scales. In this paper, we introduce a Fourier space formalism for describing the line-of-sight methods, and use it to introduce an improved new method for 21-cm foreground cleaning. Heuristically, this method involves fitting foregrounds in Fourier space using weighted polynomial fits, with each pixel weighted according to its information content. We show that the new method reproduces the old one on large angular scales, and gives marked improvements on small scales at essentially no extra computational cost. |
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| Keywords: | methods: data analysis techniques: interferometric early Universe radio lines: general |
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