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arXiv · 1710.06901

A technique of removing large-scale variations in astronomical observations

Jungyeon Cho
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Abstract

In many astrophysical systems, smoothly-varying large-scale variations coexist with small-scale fluctuations. For example, a large-scale velocity or density gradient can exist in molecular clouds that exhibit small-scale turbulence. In redshifted 21cm observations, we also have two types of signals - the Galactic foreground emissions that change smoothly and the redshifted 21cm signals that change fast in frequency space. Sometimes the large-scale variations make it difficult to extract information on small-scale fluctuations. We propose a simple technique to remove smoothly varying large-scale variations. Our technique relies on multi-point structure functions and can obtain the magnitudes of small-scale fluctuations. It can also help us to filter out large-scale variations and retrieve small-scale maps. We discuss applications of our technique to astrophysical observations.

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Jungyeon Cho. 2017-10-18. A technique of removing large-scale variations in astronomical observations. https://arxiv.org/abs/1710.06901

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