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arXiv · 0810.2825

Multi-Scale CLEAN: A comparison of its performance against classical CLEAN in galaxies using THINGS

J. W. Rich·W. J. G. de Blok·T. J. Cornwell·E. Brinks·F. Walter·I. Bagetakos·R. C. Kennicutt Jr
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Abstract

A practical evaluation of the Multi-Scale CLEAN algorithm is presented. The data used in the comparisons are taken from The HI Nearby Galaxy Survey (THINGS). The implementation of Multi-Scale CLEAN in the CASA software package is used, although comparisons are made against the very similar Multi-Resolution CLEAN algorithm implemented in AIPS. Both are compared against the classical CLEAN algorithm (as implemented in AIPS). The results of this comparison show that several of the well-known characteristics and issues of using classical CLEAN are significantly lessened (or eliminated completely) when using the Multi-Scale CLEAN algorithm. Importantly, Multi-Scale CLEAN reduces significantly the effects of the clean `bowl' caused by missing short-spacings, and the `pedestal' of low-level un-cleaned flux (which affects flux scales and resolution). Multi-Scale CLEAN can clean down to the noise level without the divergence suffered by classical CLEAN. We discuss practical applications of the added contrast provided by Multi-Scale CLEAN using two selected astronomical examples: HI holes in the interstellar medium and anomalous gas structures outside the main galactic disk.

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J. W. Rich, W. J. G. de Blok, T. J. Cornwell, E. Brinks, F. Walter, I. Bagetakos, R. C. Kennicutt Jr. 2008-10-16. Multi-Scale CLEAN: A comparison of its performance against classical CLEAN in galaxies using THINGS. https://doi.org/10.1088/0004-6256%2F136%2F6%2F2897

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