Ok, maybe I can clarify this. In the Arpian perspective a bridge is a result of interaction between two objects. A Jet is a result of nuclear activity. Both of these are the same as the mainstream view. Interaction produces bridges, disrupted morphology and tails. Jets come from nuclear activity.

The only difference is that Arp hypothesizes an ejection occuring as a result of the nuclear activity. The jet is considered a sign of that ejection process. So in Arp's view a bridge can result from the interaction of an ejected object passing through the disk of the parent galaxy (eg NGC 7603) . A bridge can also result from gaseous material being ejected with the high z object (eg NEQ3).

In the mainstream view the the interaction comes from two objects passing by each other. In Arp's view the interaction comes as a result of one object ejecting another from the active core.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

I'm interested, but not well connected. My interest goes back to a time when I was very young, and we didn't have a clue what quasars were (when 3C-273 was about the only one we'd ever seen). I knew someone was championing an idea that didn't require them to be impossibly powerful and distant. We've learned a lot since then.

My point is that I'm just an interested hack with no real connections to mainstream astronomers to encourage participation.

__________________
Forming opinions as we speak

Absurd. You can scientifically build an empirical case that something is happening without understanding why:

There was plenty of evidence for evolution before Darwin and genetic developments provided a mechanism.

There was plenty of evidence for the movement of continents before seafloor spreading provided a mechanism.

Newton provided a wonderfully useful mathematical representation of gravity without any explanation as to why gravity behaves that way.

You don't create a mechanism to explain something that hasn't been observed. And you don't say something that has empirical support could not be true simply because the development of theory is trailing behind the observations.

Do you have anything substantive to say in response to my two long posts?

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

Cougar, you never responded to post #1460 . You keep claiming the Scranton paper disproves examples such as NGC 7603. That's just not the case.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

Good. But I'm saying that the other interaction-supporting observations proposed so far can be viewed as circumstantial and inconclusive.
Well, mainstream astronomers agree that they are interacting. Lots of galaxies have bridges or wisps or whatever you want to call them, and if one object is aligned in the wisp of another, this is an indication that they might be interacting, but it does not allow us to make that a firm conclusion.

As you admit, chance projections are not impossible.

Of course it does. The paper explains why there seems to be an overdensity of quasars in the vicinity of galaxies. Because of weak gravitational lensing, the authors found that more quasars are expected to appear close to foreground galaxies. Since we know that many galaxies are interacting with other galaxies now and in the past, some of the overdensity of quasars will be aligned with the galaxies' tidal streams or wisps or other galactic structures. Some won't. The paper is directly relevant to why quasars often appear close to galaxies on the plane of the sky. Since galaxies often have structures that resulted from previous interactions, we don't need the paper to spell out the simple logic that quasars will often appear close to such structures as well.

__________________
Everyone is entitled to his own opinion, but not his own facts.

So do I have it correctly that in an Arp discussion a bridge is any luminous, or shadow (ie dark superimposed on a light background) matter seemingly connecting any two objects, or created as a result of an interaction (such as an antipodal tidal tail), regardless of cause or nature. That is, bridge is a catchall term. Does the term bridge only apply if the connection between two objects is real? If it is eventually proven that two objects are not connected does that mean that the term bridge must be removed? Also, as an example, M82 is experiencing a high rate of star forming, which is creating supernovae, which are creating numerous chimneys of gas and dust. These are a result of an interaction. Are they bridges? to what, M81?

__________________
Forming opinions as we speak

I'm not sure if I'd say "catchall". In the mainstream treatment a bridge is formed by gravitational interaction between two objects, but tidal tails can also form on the opposite side of the bridge. But in the mainstream treatment a bridge can evolve into a tail if the other galaxy moves far enough away that the "bridge" no longer connects the two objects.

There is nothing prohibiting similar changes in Arp's model. If an ejected object pulls far enough away from the parent, the "bridge" may no longer be a "bridge" but should still point toward the ejected companion.

Yes. That would definitely be the case. Obviously we have not been typing it this way every time we address it - but in the case of NGC 7603 the filament is being interpreted as a bridge between NGC 7603 and NGC 7603B resulting from interaction. If it was shown that the filament was not the result of interaction between NGC 7603 and NGC 7603B, then the filament would not be considered a bridge.

They would only be a bridge if some object was associated with the chimney activity. In general Arp would not really expect these chimney's to end with quasars because the quasars are expected to originate from activity in the active galactic nucleus (AGN).

If there was a QSO at the end of one of these chimney's my initial interpretation would be that it was an accidental projection. Now when I say that, there are two ways it could be an accidental projection. One would be that the quasar was ejected from the nucleus of M-81 and - in the process of moving outward it passed close to one of these chimney's projecting up from the disk. In other words, the QSO might still be associated with M-81, but the alignment with the chimney would be a chance projection.

The second way it could be a chance projection would be if the QSO was a background object not at the distance of M-81.

This actually leads to an important point to understand. Speaking as an Arpian, the only way I would be led to interpret the chimneys as interacting with high z QSO's would be if we started finding multiple chimney's in multiple galaxies with QSO's at the end of them. Another galaxy with these chimney's is NGC 891.

But here's the point. Arp did not just one day look at a catalog and say "Hmmm there is a qso ... and there is a galaxy. Oh they must be associated and the qso is ejected from the galaxy."

What actually happened was in the late 1960's he was sitting at the observatory one night - unable to observe because of the weather and so he was looking at radio maps of local galaxies. He noticed that the radio maps showed bipolar ejections along the minor axis of radio material - often terminating in radio hotspots. It was not a new idea even at that time to think that the radio material was ejected from the radio galaxies. But when he started cross referencing the catalogs he found that radio loud quasars were often at the location of the radio hotspots.

This pattern of discovery repeated itself in the 1990's with X-ray observations. Arp published a paper in the mid-90's showing that Seyfert galaxies had lines of X-ray sources along their minor axes. With several of these the x-rays sources were at the positions of already cataloged quasars. But many were unidentified X-ray sources. Subsequent observations revealed numerous quasars among those X-rays sources aligned along the minor axes of the Seyfert galaxies.

And its repeating itself again in the current decade with the ULX's. Many of those are turning out to be QSO's as well.

Of course none of this is specifically about the bridges, but it is relevant background. If these are all chance projections, then there should not be such reproducible patterns to what is observed. And yet we see it in radio, x-ray and optical studies.

With the bridges - the majority of the M-51 type objects with companions on the end of spiral arms have turned out to be ScI class spirals where the "I" represents the luminosity class. Luminosity class "I" spirals have very narrow arms.

The question might be asked why these chance projections (QSO's and other higher z objects such as HII galaxies) - if that is all they are - pop up mostly with AGN, disturbed galaxies, and ScI spirals.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

Well, I'm in the same boat, in my mid-50s with no formal training in astronomy beyond introductory courses and some observing time through an old Alvan Clark refractor from a light-polluted campus. I have no connections with professionals in the field apart from those established through interactions such as these, and some private correspondences when someone either liked or took issue to something I wrote in letters to magazines in the popular press. Most of my work experience and training revolved around industrial process chemistry (a much more marketable trade in Maine than astronomy) and a 5-year stint as an optician. My astronomical experience has been almost entirely self-directed. I have a 6" f:8 Astro-Physics APO, an f:5.6 Vernonscope, and a few other instruments, a really nice astronomy library, and of course the internet has been a boon,allowing access to scientific results from high-quality projects on BIG instruments.

It certainly would be nice to have people like Michael Strauss, Bill Keen, Rocky Kolb, etc, chip in here - people who are mainstream, but not afraid to push the envelope.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

I've answered many of these points in my response #1505 to Turbo.

As I said in my post I linked to above, "this is an indication that they might be interacting, but it does not allow us to make that a firm conclusion." In other words, this is supporting evidence, but it does not allow us to make a firm conclusion.

I believe my response #1505 to Turbo, my previous post to Antoniseb, and my response to your next question provide a concise rebuttal to your two long posts. Sorry if these extensive posts can be rebutted with a sentence or two, but that's the way it is.

The whole premise of your argument is weak. Homicide investigators might have a lot of evidence against a particular suspect, yet it might turn out that he's innocent.


Well, that's the question, isn't it? With our current knowledge, there is no way they could be interacting if the redshift is considerably higher. I am well aware that our scientific theories are not fixed in stone, and the book may be rewritten or modified with regard to redshift. But until it is, it does not make sense that objects with very different redshifts could be interacting. Please note I did ask, "How can we differentiate between a chance alignment and an "Arpian phenomenon"?" That is the question.

__________________
Everyone is entitled to his own opinion, but not his own facts.

How do the anomalous bridges of NGC 7603 compare to their non-anomalous counterparts?

Your post #1505 says nothing substantive Cougar. You've responded with no specifics. And you've refused to answer questions directly asked of you.


Well, like I said - and you've just proven my point - you're the one that is dealing in absolutes and "impossible". You can't even acknowledge that evidence for which you have no substantive rebuttal is in fact evidence supporting (not proving) an alternative view. The two long posts and much of what has subsequently been said provide specifics to your last question (highlighted in red). All you've been able to bring forward as "evidence" is that the redshifts are different. You're going to have to provide something else - and you haven't.

Let me use NGC 7603 to one more time illustrate just how non-substantive your responses have been. BTW - non-substantive can be ok if you're taking a weak role in the discussion - but you're making very strong claims against Arp. You have an obligation to back up your statements with actual detail. Otherwise you're making claims you cannot defend.

The premise is that an Arpian alignment should meet the criteria that mainstream astronomers consider evidence for interaction - except that in the Arpian model large redshift differentials are allowed.

The following lines of evidence (and Turbo-1 please feel free to add to this if I've forgotten something) support an interaction scenario between NGC 7603, NGC 7603B, and the two HII galaxies:

(1) NGC 7603 is a Seyfert galaxy - the primary type of galaxy that Arp argues are expected to be associated with these discordant redshift associations.
(2) The filament/bridge terminates at the position of NGC 7603B.
(3) The HII galaxies are projected inside the filament.
(4) Both HII galaxies are elongated toward the nearest galaxy (NGC 7603 for the z=0.394 HII galaxy and NGC 7603B for the z=0.245 galaxy). Such elongations and distortions are signs of interaction.
(5) HII galaxies are active starforming galaxies - another sign of interaction.
(6) The HII galaxies in this case have extremely large Equivalent widths. The z=0.394 object has a H-alpha EW of 81 A and the z=0.245 object has a H-alpha EW of 161 A. These equivalent widths are extremely large for HII galaxies. This can be seen by a look at Figure 15 of Carter et al . ** Only 8 of 641 HII-like galaxies have EW >100 A. It can also be seen in the bottom 3 panes of figure 15 that these large EW galaxies are present among the low luminosity galaxies.

Table 3 of the paper - last page of the preprint - also notes the most vigorous star forming galaxies in the sample - all with very large equivalent widths - but again - only a handful with EW > 100.

In their conclusion they state:

But tidal triggering is exactly what we would expect if these HII galaxies are in the filament and not just projected behind it.

(7) The filament must be produced by something. If you want to argue that NGC 7603B is background, then that still requires some object to have formed the bridge (a tidal tail in that case). L-C&G carefully discussed this and the only two objects at the redshift of NGC 7603 are on the opposite side as the filament. And there are no confirmed objects within 30 arc min on the same side as the filament. So if NGC 7603B is not the interacting companion then you've got smoke without fire.

(8) If you want to dispute the statistics, please show what L-C&G have done wrong. They find a probability of this being an accidental alignment of only 3 x10^9.

So the point of all this Cougar is that NGC 7603, NGC 7603B and the two HII galaxies meet the mainstream criteria for interaction - except for the redshift differentials. As such, there is empirical evidence supporting the interpretation that these objects represent a genuine case of discordant redshifts - unless you (or someone) can provide evidence (besides redshift) that the above evidence is not evidence for interaction in this specific case.

**Note - the preprint is very long (42 pages). If you want to see the published version just do an NASA ADS search for the paper. The published version was ~14 pages. Wow - how did they squeeze that 42 page pre-print into 14 pages. Cougar? You made a big deal about that with the Lopez-Corredoira paper. Any further comment?

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

That's tough to answer because there is no one type of bridge in non-anomalous systems. Sometimes they're seen in optical, sometimes X-ray, and sometimes neutral hydrogen. They may be seen in multiple wavelengths or they may not. It is well established that neutral hydrogen extends beyond the optical disk. So a bridge in neutral hydrogen can potentially occur with a larger separation of the two objects.

In the case of NGC 7603, the bridge is that of an older stellar population at the redshift of NGC 7603. The interpretation in the Arpian model then is that this is material pulled out from the disk of NGC 7603 with the outward passage of NGC 7603B. If there is higher redshift material present in the bridge it has not been detected, but that could be a simple matter of S/N ratio.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

I think this is an important point turbo-1. Its become increasingly apparent that ULX's are a big part of this story. Are the HII galaxies also ULX's. It would certainly be relevant information to have - because it is another piece of this issue.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

You are glossing over a key point, here. The Scranton et al paper that you claim kills all our arguments for the interaction of bridged objects found a statistical positive correlation between quasars and galaxies. When Arp claimed to have found such a correlation, you mainstreamers derided his work and claimed that it was faulty. When you get the same result from a mainstream astronomer, suddenly, it is correct although Arp's work still has no value for you.

As for your citation of the Scranton et al paper as a weapon against the interaction of the NGC 7603 system, it is a complete non-sequitur. The Scranton paper described a survey in which quasars showed a statistical correlation with galaxies. Where is the quasar in the NGC 7603 system? We have a Seyfert galaxy accompanied by a dwarf elliptical galaxy at the end of a narrow tidal stream, and embedded in the tidal stream are two dwarf HII galaxies. There are no quasars in the optically-visible association. I have asked you repeatedly to quote some relevant sections of the Scranton paper that address this situation, and you have not done so - you only re-assert that the Scranton paper moots this system. That paper has absolutely no relevence to the bridged objects in the NGC 7603 system.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

It will be a cold day in hell before the Chandra allocation committee gives Arp et al any observing time to study that. It's funny, because if the mainstream believes that the NGC system is not interacting, you would think that they would observe the system in every wavelength available, to support their views and spike the Arpians' claims.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

And certainly - whether you believe some HII galaxies have discordant redshifts or whether you believe all objects are at their redshift distances - any research that helps us understand the X-ray properties of star-forming HII galaxies would be useful.

I would also think that a systematic effort to get the redshifts of the M-51 types you listed would be useful information as well.

For example it might be interesting to compare the HII galaxies in the tidal bridges with HII galaxies not in tidal bridges. If the the HII galaxies projected on the tidal bridges turned out to have different X-ray properties of those that are not - then that would provide more information relevant to the question of interaction.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

It would be useful, yes, and quite easily done with today's better instruments. It would also be instructive to review the associations with zero published redshift differential, since the redshifts might not have been measured individually, but "assigned" with the assumption that interacting objects have the same redshift. If you look up a few of these systems in NED, sometimes the published redshift of the system does not agree with the published redshifts of any of the members of the system.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

It will be important to cross reference the objects with the redshifts in HyperLeda - which has compiled the 2dF,2Mass, and SDSS redshifts. It is something I haven't yet found time to systematically go through and do.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

If you can give me links and a good procedure for extracting the redshift information, I will gladly volunteer the time to get the data. I think that it is important, and I would love to extend the redshift differential information for bridged systems.

Edit: I found HyperLeda but have not gotten to the point where I have found redshift information. Let's establish a criterion by which the redshift information can be obtained, and I will go through the entire list of objects that I scoured NED for. I am very interested in seeing if the relationships that I found previously are maintained. For those who may have joined this thread recently, there are twice as many redshifted small companion galaxies as redshifted large host galaxies, and the magnitude of the redshift differential is twice as large when the companions have the excess redshift.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

You may not like the reality of my post, but it is substantive and simple logic that obviates the conclusion that two or more objects with "discordant" redshifts are interacting.

I'm willing to look at other examples and review the evidence, but I don't have an infinite amount of time. (That's not a criticism of anybody, just an unfortunate reality.)

That's exactly what I'm saying: There is supporting evidence, but it doesn't prove interaction, which would require an alternative explanation for a very high redshift object nowhere near the distance away it should be.

It has been pretty firmly established that redshift and distance are tightly correlated. I don't have to establish that. If you want to establish that there is another component of redshift that can mimic the effect of light traveling through several billion lightyears of expanding space, which has a considerable redshifting effect, it is you who is going to have to provide something else.

As I said, I'm willing to look at other examples, but how about one at a time? I haven't seen many details about the comparative absorption lines of these objects with significantly discordant redshifts.

Coincidentally the type of galaxy that has likely had a significant interaction at some time in the past, leaving it "disturbed", with tidal tails, etc.

It seems to for the most part, but that's a pretty "looks like" assertion. Also, 7603B's redshift is beyond what is normally considered "interaction range" but not tremendously so.
One paper has tabbed these with considerably higher redshifts than NGC 7603 or NGC 7603B. The higher the redshift differential, the more pressing the question, "How could they possibly be within the filament or even within the same region of space as NGC 7603 or 7603B with such different redshifts?" If they are really within the filament, this would obviously require an explanation how their spectra could be redshifted so far beyond what their distance would indicate. But there's really no explanation - just a variety of speculations.

Wouldn't they be spinning? Even if they are pointing at the nuclei of the larger galaxies (which I don't think they are exactly), given the complex dynamics of a hypothesized interaction, I'm not sure they should still be elongated along such lines.
Is the type of interaction you're talking about the only way HII galaxies form? See response to your next point.
HII galaxies are born within HII regions, which can be more than 1,000 lightyears across. And recent observations have shown that a small number of H II regions exist outside galaxies altogether.

HII regions may have been larger in the past because the density of the universe was greater. How do the 641 EWs break down by redshift?
I don't have any great explanations for this, but there are some mainstream possibilities. (A) The two galaxies did interact in the past, and 7603B got flung into the background at a high rate of speed. As I said, the difference in their redshifts is greater than normal for interacting galaxies, but not tremendously so. (B) The interloper that caused the filament would not necessarily still be on the same side as the filament. Is it inconceivable that it is outside the region investigated by L-C&G?
I think I have previously expressed my problem with this kind of statistics. As Bill Keel has pointed out, "Various papers dispute probabilities by factors of 10^7."

There is more to your evidence than just "looks like," but nothing that requires a firm conclusion.

Well, I've given some speculative mainstream explanations for the discordances, and Arp and others have given various extremely ATM speculative explanations how the redshifts could be falsely indicating distance differences where there is no distance difference. I'm not making any ATM assertions. I think the burden of proof is on the person doing the asserting.

__________________
Everyone is entitled to his own opinion, but not his own facts.

Cougar, you have conveniently chosen to avoid the points I raised in post 1514. Short attention span? Your continual citations to an irrelevant paper are done and over right HERE AND NOW unless you can provide any support to your extreme claims.

This is the time to put up or shut up.

If you can provide relevant references and explain WHY they are relevant (a new one for you!) perhaps we can continue.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

Get in line.

__________________
Everyone is entitled to his own opinion, but not his own facts.

Go to HyperLeda, click "Search by name", write the name of the object to "Object designation" box and click "LEDA (expanded display)". Redshift is given as velocity values in the resulting page. Note that if the object you're searching doesn't have redshift data, the resulting page doesn't contain any mention of velocities, not even empty velocity rows.

If you find some of the missing redshifts, let us know. At least I'm interested in them.

__________________
"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

The discordant redshift v distance suggestion is interesting. Does that not also imply there should be discordant redshifts in Cepheid's? Granted, NGC 7603 is probably too distant to resolve Cepheids, but if the anomalous redshift interpretation is correct, shouldn't there be similar inconsistencies? Also worth considering is the NGC 7603 bridge itself. It is a pretty unique structure irrespective of any potential associations with other objects. I'm not aware of any other comparable structures. While interesting, that particular example is too freakish to be convincing. I don't see a case for alternative physics until a consistent pattern of related examples is demonstrated.

Thank you Ari. I tried that with a couple of objects and didn't see the redshift data - I thought that I was doing something wrong.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

I don't claim it kills all your arguments. I claim it undercuts the typical Arpian "statistical" a posteriori arguments that multiply perceived likelihoods of certain configurations and tell us the chance of such configurations are "a million to one" or some such. Nobody liked such statistical tactics when they have been presented, and now Scranton et al. have shown that they are essentially invalid due to incomplete information. It's very reminiscent of creationists arguing that the odds of life arising on Earth are beyond astronomical. But they're working from incomplete information and exaggerated assumptions.

__________________
Everyone is entitled to his own opinion, but not his own facts.

Apparently you didn't bother reading my post.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924

And there is your problem. You have not presented any evidence that rules out the interaction interpretation of the NGC 7603 system - and yet you actually think you have.

There are plenty of examples to discuss in the 2 longs posts. If you're bored with NGC 7603 - move on to one of those. I don't have infinite amounts of time either.


The alternative explanation is irrelevant. We're talking about whether or not bridges and the other forms of evidence are evidence for interaction. If it is established that they are evidence, then you look for an explanation. What you and others love to do is claim that the lack of an established mechanism to explain it is disproof of the possibility. That's absurd as I explained to Thanatos .


Which in no way rules out the large redshift deviations we're discussing. and the topic of just how "tightly" redshift and distance actualy correlate is worthy of discussion at another time - but as we're both saying - we're quite busy people.

But let me repeat one point I've made a number of times in response to this point of yours. The number of galaxies with redshift independent distances is tiny compared to the number of galaxies observed in the universe. In cases where there are large deviations between the distance determined by whatever method you choose and the redshift distance, it is assumed that peculiar motions or distance errors are the reason for the discrepancy.

So the question is - how do we establish for sure - that the Hubble relation is as tight as you believe. We must find ways to establish the distances to objects. One of the ways we can do that is by demonstrating that two objects are interacting. And when we do that - and the redshift differences turn out to be large - then the mainstream tosses out all that interaction evidence that they normally accept.

But I would agree that the Hubble relation is very tight - after one dismisses all the examples that show a large deviation from the Hubble relationship.

Nope, I don't have to come up with a mechanism. As much as some of you try to make that the issue, that's not what we're discussing. We're simply discussing whether or not there is empirical evidence supporting the interpretation that some objects can have large deviations from the Hubble flow.

We haven't gotten to that stage yet - nor is it necessarily the case that the data needed to discuss that has been collected.

AGN activity has not been shown to be correlated with interaction. Here too

It's not even close Cougar - that's the point. If NGC 7603B was anywhere near a redshift differential that was acceptable for interactions - the mainstream view would be that this is a high velocity encounter - because as Turbo-1 and I have noted - there is plenty of evidence consistent with an interaction scenario.

You keep trying to make that the issue. Its not.


At the distance of NGC 7603 they would be dwarf galaxies - which have very low rotational velocities. And even if they have some spin that does not preclude the possibility of interacting tails.

No. Does the fact that they might form in a number of ways eliminate the starbursting nature of these objects as evidence for interaction?

They don't all form that way.


It would be easier if you look at the figures in the paper.

These filaments are transient objects in the gravitational interaction scenarios (see Toomre&Toomre). If you start talking about objects any further, then you get into a situation in which the interaction would have been too long ago to explain the current existence of the filament.

We're not talking about "various papers" - we're talking about this paper - which is very recent. Is there a blatant flaw in those statistics?

I'm not even going to bother digging up the quotes from previous posts. I've never said that there is a "firm conclusion". I've simply said that there are multiply lines of evidence supporting interaction and that the mainstream has not provided any evidence that any of those lines of evidence can simply be dismissed in the NGC 7603 case (or any of the others for that matter).

Don't waste our time with "burden of proof". We're having a dialogue (in theory anyway). A scientifically viable case for interaction of discordant redshift objects has been presented - a case supported by empirical evidence. Saying the "burden of proof" falls on us without offering any compelling rebuttal to the evidence presented simply allows you to avoid acknowleding that there is evidence Arp et al might be right.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

Well, that may depend upon the mechanism for anomalous redshifts - which is unknown. It would also depend upon the specific object. NGC 7603 may not have a large intrinsic redshift - just the objects associated with it. But it has been argued that some galaxies too have anomalous redshifts. Arp also had a 1992 paper arguing that young stars within our galaxy show a slight intrinsic redshift.

We're not talking about alternative physics. We're talking about whether or not there is evidence for discordant redshifts. If there is such evidence, then you worry about the implications (mechanisms, new physics ...).

Nor is NGC 7603 an isolated example. But I agree - it would be a huge help if the Arp and Arp/Madore catelogs category of M-51 type objects had a complete survey of their redshifts. As it stands most of the M-51 type companions do not have measured redshifts. But the recent surveys have measured a few of them that previously had not been measured - and some of those do in fact have discordant redshifts.

__________________
"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known."

~Timothy Ferris (The Red Limit) 1982

Here are the bridged Arp and Arp-Madore associations for which I previously extracted redshift differential information from NED. HyperLeda yeilded some additional redshifts, although the Arp-Madore catalog is still very poorly represented in the data. There are no longer any 0 redshift differentials in the sample, thanks to the data in HyperLeda. There are 12 associations in which the larger host galaxy is redshifted WRT the smaller companion. The average redshift differential for the group is -76.5 km/s, in good agreement with my first cut at this project (NED only). There are now 39 associations in which the smaller companion has the excess redshifts, with an average differential of 5980 km/s. If we throw out all the associations with redshift differentials >1000 km/s, we end up with 30 bridged associations in which the smaller companion exhibits the excess redshift, with an average differential of 160.6 km/s.

Ignoring the 9 associations with redshift differentials >1000 km/s, companions are 2.5x more likely to be redshifted than their hosts, and the magnitude of the average redshift differential is 2.1x larger than that observed when the hosts are redshifted WRT the smaller companions. All redshift differentials are expressed as heliocentric recessional velocity.

__________________
The ether of general relativity therefore differs from that of classical mechanics or the special theory of relativity respectively, in so far as it is not 'absolute', but is determined in its locally variable properties by ponderable matter.

Albert Einstein, "On the Ether", 1924