\[fig:sfind\_aper\] we compare flux densities obtained with the two methods mentioned above. Above 10[$\,\mathrm{mJy}$]{} they are generally consistent with each other. However, the aperture flux densities seem systematically higher for sources below 10[$\,\mathrm{mJy}$]{}. This is expected because the aperture can pick up flux densities that are: 1) not well cleaned; 2) buried in noise due to low surface brightness. The aperture is probably superior to <span style="font-variant:small-caps;">sfind</span> for measuring total flux density. The aperture flux density is also better for large extended source as de-blending is not necessary. However, the aperture is not optimized on the radio image itself so that it may include too many empty sky pixels, reducing the signal-to-noise ratio. This has strong impact on detecting weak point sources. The aperture flux density is also more prone to image artefacts, such as cleaning residuals of nearby strong sources. We are not able to totally rule out the possibility that the aperture flux density excess in low flux density region is due to image artefacts. However, it will not affect the main result of this paper.

For final flux density catalogue (Table \[tab:flux\]), we adopt aperture flux densities first if above 3-$\sigma$. There are 18 galaxies with aperture 