Jim
'Late type' only refers to the Hubble tuning fork sequence not late in evolution. There is no link between 'time' and 'early' and 'late,' types, very misleading for non astronomers I agree. In fact in terms of stellar age the converse is true, the 'cold inner regions' are most prevalent in the younger more open spirals. In those cases the AGN is weak and relatively dormant, so minimal perpendicular outflows, (as the Milky Way). In (stellar) population age terms, (blue = young red = old), and the reddest are the most blended discs with the most predominant bulges.
The motion shown in the Ganda Fig's is the same as all (the very many) others, rotational velocity. NOT radial velocity. This is why one side is shifted to blue the other red, the blue side is approaching us, the red receding). This is as originally found in the kinetic SZ effect. Ganda was indeed followed up, with dozens more comprehensive studies and other authors (it was 2005!) but as I complained, most are not 'free for view'. I can read then as a fellow of the RAS, but most have to pay. The most definitive is probably my reference 9. One good recent one on arXiv is here, clarifying the above; http://arxiv.org/pdf/1001.3138.pdf
Few astronomers 'presume' exotic Dark Matter', though I agree wrong assumption is rife, and yes, many do indeed 'roll their eyes' and ignore my thesis too, even though it's the only one so far that fits both the data and observational evidence perfectly! And plasma is certainly NOT 'non emitting'! The whole point is; my essay agrees that it absorbs and emits BETTER than any other known substance, but refractive index n=1 means the only observable effects are kinetic (if it is 'moving').
All collisions I know also lens from distorted electron halo components, that is the whole point of my Fig.1 which shows precisely this, but which you approached from a viewpoint formed by set of inaccurate assumptions, so the conclusion in your penultimate paragraph is not consistent with the evidence. I'm certain someone somewhere postulates they don't, but do pass me any evidence (based on data) of that.
I hope that fully clarifies all your points, but if not please do read the above link before reverting. I'm sure there are now also more on arXiv.
Best wishes
Peter 23.9
Jim
Do you realize the term 'velocity dispersion' has nothing to do with 'direction'? It is a notional value of relative speed range 'spreads'. I repeat, and I'm sorry, but it seems both you and Mario have misinterpreted the terminology'; there is no implication of any but trivial radial motion in Ganda Fig 5a, and more disc plane inflow (jet 'feedback') than outflow in Sauron findings. A good intro overview to help is in this presentation. http://www-obs.univ-lyon1.fr/labo/perso/jeremy.blaizot/Presentations/emsellem.pdf my essay (and last years) fills in some missing gaps, but it's a good start. A more complete list is here; http://www.strw.leidenuniv.nl/sauron/publications.html
The kSZ is not just 'found in the...etc.' as you seem to assume, It is a common 'effect' consistent with all findings of galaxy kinetics.
Yes, very familiar with collisions and bullet cluster, and the lensing CANNOT be explained without the distorted clouds, as the text in the link confirms. Your comments don't make sense, I assume as based on misunderstandings. The affected ion densities of ALL collisions (there are really not that many) studied affect lensing patterns. Yes it is assumed as 'dark matter', but no, though it DOES have to be something with gravitational potential matching halo interaction evolution it may just as well be plasma because plasma n=1. There are still many different opinions on what that unidentified ('dark') matter is, including many agreeing baryonic including MACHO's. Yes, most do assume the matter is there, but for much more sound reasons than you seem to realise. Your suggestion would need to show how it can fit the data to offer your proposal any support. It certainly looks unable to do so at present, so you have to show how with some pretty detailed data analysis not to be laughed off.
I can see the free link was 'no value' to your thesis, but it is of truth value! I looked at your link to the M51 Density Wave paper, which again finds no net radial outflow, confirming (1141) the "CONTOURS of the projected velocity field are purely radial." Also, as I said; "that out-of-plane motions are significant."and suggesting (1157) "the input spiral pattern vanishes in less than one orbital timescale (~200 Myr)" Supporting the evolution sequence of spiral to lenticular (SO) which I identify.
Sorry Mario, but it is also in response to your false accusations that I was 'wrong'. I'll re-post this on Jim's string in case there are more questions. Time to face facts about the cited 'evidence', but I repeat, I agree there are very many fundamentally wrong assumptions in astronomy, and 'patch' atop 'patch,' most from trying to be consistent with SR. All attempts to challenge assumptions should be encouraged, but also well evidenced.
Best wishes
Peter