http://heritage.stsci.edu/2002/23/supplemental.html
Discusses this and apparently somebody cared enough to put the Hubble on it.
First, they don't mention plasma ... seems everything is neutral "gas" to these folks.
Second, they say "Enhanced stretches of the HST image show a debatable 'luminous bridge' between NGC 4319 and Mrk205"
I'll certainly agree it's debatable but perhaps it would help if they processed the image in a different way. Here's what others were able to get out of the Hubble images with better processing:
http://www.astr.ua.edu/keel/galaxies/hhn4319a.jpg
http://www.haltonarp.com/articles/rebuttals/illustrations/mk205a-neg.jpg
http://www.skepticalinvestigations.org/controversies/Arp_controversy.htm (see the CCD image by David Strange)
Some of those shows a more defined bridge. And make me doubt the claim of the author that there are similar "gas" features around the galaxy and quasar. But it is debatable.
Third, there seems to be some confusion in that source. First it states that "In time, many quasars were found to lie in galaxies with exactly the same redshift, providing powerful evidence that quasars are an event that occurs in the nucleus of galaxies." Then it states "Today the redshift controversy has almost faded from view. Only a few astronomers still think there is reasonable evidence for noncosmological redshifts". Those seem to be contradictory statements.
This page at least discusses the ESO 1327-206 galaxy and quazar and says that the galaxy's spectrum is superimposed on the quazar.
http://www.astr.ua.edu/keel/agn/redshifts.html
Yes, that's an interesting case. That's why I mentioned it earlier.
And a google search for the Fornax quazars NGC 1097 A (of which there are a bunch) show more than just Arp being interested in it. hardly what i would call squelched.
I'm not saying it's been totally squelched, just that there's a certain ... shall we say ... .disinterest on the part of the mainstream astronomical community. For one thing, they choose to treat each case as individual rather than look at the likelihood that all are just optical illusions.
And this article discusses the NGC 7320 and NGC 7320 C redshifts:
http://www.spacetelescope.org/news/html/heic0007.html
And what does it say? That "A few hundred million years ago the galaxy NGC 7320C (just outside the left-hand edge of the Hubble image) passed through the group from behind (as seen from Earth). It collided with the galaxies in the group, ripping out gas and stars to form a long tidal tail as it flew by. ... snip ... Their observations revealed that all but one of the galaxies are receding from Earth at about the same velocity (~6000 km/s). The discordant galaxy (NGC 7320 seen in the bottom of the Hubble image) is receding much less rapidly (~800 km/s). Some astronomers saw this as evidence that redshift is unrelated to distance, opposing the idea that the Universe is expanding. However, today there is general agreement that NGC 7320 is merely a foreground galaxy, 35 million light years away, projected onto the more distant (270 million light years) compact group by chance. ... A few hundred million years ago the galaxy NGC 7320C (just outside the left-hand edge of the Hubble image) passed through the group from behind (as seen from Earth). It collided with the galaxies in the group, ripping out gas and stars to form a long tidal tail as it flew by."
Now let's see, what did they leave out of the above description? That there is ALSO a tail coming out of NGC 7320 (the one that's supposedly 8 times closer than the others) that sweeps around in an arc directly towards NGC 7320C. The one out of NGC 7319 is only in the general direction of NGC 7320. You can see an image of this here:
http://www.electric-cosmos.org/arp.htm . If an encounter with NGC 7320C is what caused the tail of NGC 7319 to point in its general direction, what caused the tail that's clearly coming off NGC 7320 which is supposedly many times closer? They and other sources dismiss this as a chance alignment (and maybe it is) ... but it must be a *really* chance alignment since now we have NGC 7320 sitting exactly on a tail that sweeps directly into NGC 7320C. But like always, they threat the alignment in isolation from all the other "chance alignments" Arp noted. Looked at probabilistically, that's not a reasonable thing to do. Sure, some of them may be chance alignments. But all of them?
And again we have an article that talks about "gas" and never mentions plasma.
You might find this source of interest (another chance alignment?):
http://www.aanda.org/index.php?option=article&access=doi&doi=10.1051/0004-6361:20034260
"The field surrounding NGC*7603: Cosmological or non-cosmological redshifts? ... snip ... Abstract
We present new observations of the field surrounding the Seyfert galaxy NGC*7603, where four galaxies with different redshifts*-*NGC*7603 ( z=0.029), NGC*7603B ( z=0.057) and two fainter emission line galaxies ( z=0.245 and z=0.394)*-*are apparently connected by a narrow filament, leading to a possible case of anomalous redshift. The observations comprise broad and narrow band imaging and intermediate resolution spectroscopy of some of the objects in the field. The new data confirm the redshift of the two emission-line objects found within the filament connecting NGC*7603 and NGC*7603B, and settles their type with better accuracy. Although both objects are point-like in ground based images, using HST archive images we show that the objects have structure with a FWHM = 0.3-0.4*arcsec. The photometry in the R-band obtained during three different campaigns spread over two years does not show any signs of variability in these objects above 0.3-0.4*mag. All the above information and the relative strength and width of the main spectral lines allow us to classify these as*HII galaxies with very vigorous star formation, while the rest of the filament and NGC*7603B lack star formation. We delineate the halo of NGC*7603 out to 26.2*mag/arcsec 2 in the Sloan r*band filter and find evidence for strong internal distortions. New narrow emission line galaxies at z=0.246, 0.117 and*0.401 are also found at respectively*0.8, 1.5 and 1.7*arcmin to the West of the filament within the fainter contour of this halo. We have studied the spatial distribution of objects in the field within*1.5*arcmin of NGC*7603. We conclude that the density of*QSOs is roughly within the expected value of the limiting magnitude of our observations. However, the configuration of the four galaxies apparently connected by the filament appears highly unusual. The probability of three background galaxies of any type with apparent B-magnitudes up to*16.6, 21.1 and*22.1 (the observed magnitudes, extinction correction included) being randomly projected on the filament of the fourth galaxy (NGC*7603) is . Furthermore, the possible detection of very vigorous star formation observed in the HII*galaxies of the filament would have a low probability if they were background normal-giant galaxies; instead, the intensity of the lines is typical of dwarf HII*galaxies. Hence, a set of coincidences with a very low probability would be necessary to explain this as a fortuitous projection of background sources. Several explanations in terms of cosmological or non-cosmological redshifts are discussed."