buma, there are several ways to check that, one of the best ones is redshift - it's, roughly, a measure of distance along line of sight. If they have similar redshifts, then they are interacting.
You can look for signs of interaction - see that bright blue bumpy strip in the middle? that's star formation triggered by the interaction!

I do merger of galaxies for a living. any questions, please dont hesitate!

all the monastery is really, really beautiful!

That site is really something! I've been working with SDSS for my work and at a point I had to classify almost ten thousand galaxies by eye. A little help would be greatly appreciated! :)

Those are quite nice actually.
But let's keep in mind - portuguese people DO NOT look like that...