You know those connections between galaxies? The ones that don't exist, casting a pall over Arp's insistences that they do?
Well, now, they're proof of dark matter
They combined lensing images from more than 23,000 galaxy pairs located 4.5 billion light-years away to create this composite image or map, which, they say, shows the presence of dark matter between the two galaxies. In other words, it’s a dark matter bridge, according to these astronomers.
I'd be interested to find out what the redshifts for this pair are, since Arp noted in his observations the appearance of filaments and connections between quasars and active galaxies. Does that bridge dissipate, or hang around, harder to see, as the quasar gets older (and in Arp's views, would step down in redshift?)
I'm not discounting their observations outright, but I'll be looking at them quizzically if these filaments start turning up in droves, because that would beggar explanation.