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Lookup NU author(s): Dr Christopher Hales
This is the final published version of an article that has been published in its final definitive form by Oxford University Press, 2012.
For re-use rights please refer to the publisher's terms and conditions.
We present blobcat, new source extraction software that utilizes the flood fill algorithm to detect and catalogue blobs, or islands of pixels representing sources, in 2D astronomical images. The software is designed to process radio-wavelength images of both Stokes I intensity and linear polarization, the latter formed through the quadrature sum of Stokes Q and U intensities or as a by-product of rotation measure synthesis. We discuss an objective, automated method by which estimates of position-dependent background root mean square noise may be obtained and incorporated into blobcat's analysis. We derive and implement within blobcat corrections for two systematic biases to enable the flood fill algorithm to accurately measure flux densities for Gaussian sources. We discuss the treatment of non-Gaussian sources in light of these corrections. We perform simulations to validate the flux density and positional measurement performance of blobcat, and we benchmark the results against those of a standard Gaussian fitting task. We demonstrate that blobcat exhibits accurate measurement performance in total intensity and, in particular, linear polarization. blobcat is particularly suited to the analysis of large survey data. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.
Author(s): Hales CA, Murphy T, Curran JR, Middelberg E, Gaensler BM, Norris RP
Publication type: Article
Publication status: Published
Journal: Monthly Notices of the Royal Astronomical Society
Print publication date: 11/09/2012
Date deposited: 30/06/2017
ISSN (print): 0035-8711
ISSN (electronic): 1365-2966
Publisher: Oxford University Press
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