We use two different methods to measure the 1.4 GHz flux densities of our LVHIS galaxies. Here we briefly describe the methods and discuss the reliability of the measurements.

### SFIND flux density

We use the <span style="font-variant:small-caps;">miriad</span> task <span style="font-variant:small-caps;">sfind</span> to detect and measure the radio continuum flux densities of our galaxies. We use the default false discovery rate (FDR) algorithm [@2002AJ....123.1086H] for source detection. We set the “smoothing” box size (parameter “rmsbox”) as 200 pixels (300 arcsec), to make sure the background noise can be determined from a sufficiently large source-free area. We set the default percentage of acceptable false pixels (parameter “alpha”) as 2.0%, corresponding to a $\sim4$-$\sigma$ threshold for our images. We also compare the result with the output of a previous <span style="font-variant:small-caps;">sfind</span> algorithm based on simple sigma clipping[^2]. The flux density difference between the two methods is negligible for our galaxies.

We match the detections with optical/[[$\mathrm{H}\textsc{i}$]{}]{} positions. We check the matching by eye to remove false matching, which is more likely to happen when the radio source is clearly extended or the target galaxy is not detected at all. The flux densities and their uncertainties are directly extracted from the <span style="font-variant:small-caps;">sfind</span> output 