Interestingly, the SDSS interactive learning site http://cas.sdss.org/dr3/en/ lists NGC 7603 and PGC 07041 as an interacting pair of galaxies, although their redshifts are very different. Go to the page below and find the image of NGC 7603 and PGC 07041. Click on the image to use the SDSS viewer. Click on the center of each galaxy and see its properties in the window at the upper right (note the redshifts). Then click on the two small bright knots embedded in the connecting arm. http://cas.sdss.org/dr3/en/tools/places/page5.asp Arp, the Burbidges and others have been pointing out for many years that there are interacting celestial bodies with widely disparate redshifts, so there must be at least one strong cause for redshifts that does not arise from cosmological expansion or proper motion.