Andy Goulding, a postdoc at Princeton, has been investigating the photometry of merging galaxies. He has compared the photometry of bright galaxies in HSC to SDSS and found that the scatter is quite large. There are a couple of different problems that could be the cause of this. One potential problem is that galaxies are being shredded into multiple objects and thus the HSC flux is underestimated. Another problem could be that cmodel is getting the radius too large which could result in an overestimate of the flux. I am attaching two files with a list of overestimates and underestimates as compared to SDSS.

I did an initial comparison on the underestimated fluxes when looking in a single band to see if there were degenerate templates. It appeared that this could solve some of these problems, but this should be re-examined once DM-7821 has been finished.