Detection of Faint Compact Radio Sources in Wide Field Interferometric Images using the Slope Stability of a Contrast Radial Function

PARACAULA, M.; FREIXENET, J.; LLADÓ, J.; MARTÍ, J.; PAREDES, J. M.

PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF THE PACIFIC

UNIV CHICAGO PRESS

Año: 2009 vol. 411 p. 255 - 260

0004-6280

Wide field interferometric radio images often contain a remarkable population of faint compact sources. Due to their low intensity/noise ratio, these objects can be easily missed by automated detection methods. We present in this paper a novel detection algorithm based on the structural behaviour of the neighbourhood around each studied pixel. This structural analysis is performed by defining an intensity contrast radial function and analyzing the behaviour of its slope. Our method allows using very low thresholds for the detection of sources with intensities similar to noise levels. As an example we show the validity of our approach with an image from the radio surveys recently performed in the Cygnus OB2 region using the GMRT interferometer at 610 MHz.