The skeptic in me believes that's just an exaggerated myth.Originally Posted by turbo-1
Order of Kilopi
The skeptic in me believes that's just an exaggerated myth.
Everyone is entitled to his own opinion, but not his own facts.
Administrator
Do you have any way to substantiate this?It is not politically correct to do spectoscopy on Arp or A-M associations
Forming opinions as we speak
Established Member
From the Sharp paper on NGC 7603 that you linked:
http://adsabs.harvard.edu/abs/1986ApJ...302..245S
(highlights mine) If a mainstream astronomer encounters resistance when asking for telescope time to study an anomalous system, and sticks his neck out by describing that experience in a paper, I suggest that we believe him. The fact that he refrained from naming the colleagues who supported him (apparently to protect their reputations among the mainstream) speaks volumes.
Order of Kilopi
Highlights mine.Sharp: I am grateful to those who supported me, including the time allocation committees of the AAO, the MSSSO, and the KPNO.
Everyone is entitled to his own opinion, but not his own facts.
Established Member
So, the fact that these time allocation committees allowed him to study NGC 7603 in an attempt to refute Arp's conclusions makes this part false?
Do you think that Sharp wrote this just to tick off the mainstream? Do you think that he just made up the part about encountering resistance? Why would he do that? He is simply acknowledging what Arp and his collaborators have been saying for years.However conventional the conclusions, there is considerable resistance to work on anomalous systems
Order of Kilopi
Well, in the image below we have evidence for interaction - the one object is elongated in the direction of the other. I haven't seen the spectroscopy, but I would bet these objects have discordant redshifts. Should we demand there is an intrinsic redshift explanation?
. . . . Courtesy J.C. Casado
Everyone is entitled to his own opinion, but not his own facts.
Order of Kilopi
Or how about this one from yesterdays APOD? Forget what the mainstream caption claims. The mainstream can't be trusted. Surely that one object is being ejected from the ring nebula - it's pointing straight at its birthplace. Clearly there's a bridge between the two. And the redshifts are so discordant! The evidence is overwhelming. We must demand an intrinsic redshift explanation at work here (with as yet uncertain mechanism), mustn't we?
Everyone is entitled to his own opinion, but not his own facts.
Established Member
Why don't you quit this nonsense and come up with something worthwhile?
Order of Kilopi
You don't see the relevance to this discussion?
Everyone is entitled to his own opinion, but not his own facts.
Order of Kilopi
Do you deny there is evidence for interaction, especially in this image?
Isn't this line of evidence the same as one of the lines of evidence being put forward by the Arpians?
Everyone is entitled to his own opinion, but not his own facts.
Established Member
Well, let's check out your question. In the last few weeks, some of the lines of evidence for bridges have been laid out. Optical evidence, as well as views in Xray, infrared, deep images, etc. There are bridges consisting of elongated H1 plumes or Xray filaments. Bridges have the same redshift as one of the bodies. Bridges are indicated when isophotes around the 2 objects are elongated in the direction of each other. The bridge exactly ends on one body, and if it does not end on the other, it points or curves toward it, and does not extend past it.
So if you believe you have observed a bridge, you will write a paper or article on it and perhaps convince someone to look at it, maybe months or years later. The objects in question rarely show proper motion, so should look unchanged in the ensuing time period.
So you convince me to look at your object, and the picture a few weeks or months later looks like the one in your link that you get by scrolling down a few lines to the highlighted phrase "motion of the comet". I click on it and see that there now is no bridge at all. So, after giving you a funny look, I ask why you didn't make observations in Xray, infrared, get deeper images, get H1 data, look for isophote elongation, etc, etc.
The answer in this case was simple. Unfortunately, not all cases are simple. It is after you do all these things that you make a claim for a bridge. Now, if we can only convince the people who have the instruments to take more of these kinds of readings.
TomT
Established Member
Cougar, in the past couple of months, we have presented ample evidence for interaction between objects of discordant redshift - evidence that goes far beyond the mere physical alignment of the objects. We have also been performing independent statistical analyses of apparently-interacting systems to learn more about them. During this time, you have done your best to bury this work in mere nay-saying and irrelevance, including bouts of amnesia regarding the contents of papers that you yourself have posted. Now, you try to single-handedly roll back months of hard work by "presenting" our work in a decidedly dishonest and cynical way.
I have done my best to be civil when you play games like this, mostly because Nereid, Thanatos, etc will not participate, and you're the only mainstreamer left. If you are not going to contribute as a voice of reason for your side (the mainstream), perhaps we will have to declare victory on this point (bridges between objects of discordant redshift are evidence for intrinsic redshift) and move on. Certainly, if the other mainstreamers could point out some weaknesses in our approach to-date, they would be jumping all over us with their "glee and fervor" instead of lurking. Their lack of participation (after earlier expressing great interest in an organized exploration of Arpian ideas) should be telling you something.
Antoniseb has conceded that there are some interesting trends in the redshift data accompanying the M51-type associations that I surveyed, but says he needs to see more data. As Sharp said in the paper you cited, "there is considerable resistance to work on anomalous systems", and given this resistance by the establishment, it is unlikely that the missing redshifts of the apparently-interacting Arp and Arp-Madore systems will be forthcoming. Of course, if the mainstreamers wanted to prove Arp wrong, they could get redshifts for those objects in very short order, make their case, and bury the intrinsic redshift idea forever. The fact that this has not been undertaken is probably the best evidence that the mainstream fears Arp is right - they don't want to provide him with any more NGC 7603s with which he can beat them about the head.
Order of Kilopi
Well Cougar, you've done a great job with these two examples of illustrating the difference between a chance alignment with no scientific basis for real association and the examples we've been discussing.Well, in the image below we have evidence for interaction - the one object is elongated in the direction of the other. I haven't seen the spectroscopy, but I would bet these objects have discordant redshifts. Should we demand there is an intrinsic redshift explanation?
. . . . Courtesy J.C. Casado
I'm not going to repeat the in-depth summaries I've provided for NGC 7603 and how that evidence goes beyond "just looks like". But I would point out that in this instance of the picture you've provided we have evidence that rules out any real association.
The comet is within the solar system as indicated by its observed motion. The galaxy in question is M-31 which has a distance measured by Cepheids of 790 kpc - which places it well outside the Milky Way galaxy and therefore well beyond our little solar system.
If you or anyone else has evidence that NGC 7603, NGC 7603B and the two HII galaxies are not interacting besides the claim that their redshifts are different, we'll be glad to look at it. But after 6 weeks such evidence has not been brought forward.
Order of Kilopi
Hogwash. I'm just trying to keep you and your line of argument honest.... and to occasionally remind someone that science is different than cheerleading.
I wasn't aware your months of hard work proved anything.
Well, I'm not playing games, and you're welcome to be as uncivil as you like. I have no control over you, nor you over me.
I believe my recent posts are steeped in reason. The image examples were not put forward as serious companion candidates; they were put forward as appearing to have some of the characteristics of "connection" that have been used as pieces of evidence in more serious candidates. The point is, evidence is not always as it seems.
I don't think anybody ever said this wasn't evidence. The question often in contention is whether the bridge is genuine, which from this distance isn't always easy to tell.
Your approach is too modest. There is no proof of interaction, so there's no proof of intrinsic redshift. What's to attack with glee and fervor?
You're welcome to work on anomalous systems as far as I'm concerned.
Everyone is entitled to his own opinion, but not his own facts.
Established Member
Yes.
Cheers.
Established Member
Yes and no.
Cheers.
Established Member
Anybody following this thread for the past couple of months can easily see that the ATM contingent has been hard-working and diligent, and has been providing citations to support observations and statistical trends. You have contibuted nay-saying, non-sequiturs, and bouts of amnesia designed to make us go back and re-cover things that were covered thoroughly in previous weeks.
We are the ones using the scientific method, and you are the one blindly cheerleading for the mainstream. You can get on the field and play against us, or you can cheerlead. So far, your involvement in the discussion hasn't gotten past "we're right and you're wrong, so there". Cheerleader.
Established Member
Indeed so. As I said about Cougar's attitude a few days ago:So far, your involvement in the discussion hasn't gotten past "we're right and you're wrong, so there". Cheerleader.We are still waiting for some serious discussion by mainstreamers of the discordant redshift observed in the M51-type associations presented over the past few weeks.
As regards Cougar's latest offering (the comet - galaxy "association") I assume that the other mainsteam contributors are actually cringing with embarrassment at its startling ineptness.
Established Member
Actually, there are no other mainstream contributors (excepting anoniseb, who feels that his hands are tied by his mod status). The mainstream "contributors" will stop lurking and start contributing only when they think that they can win a round. I don't think we'll see them on this thread for a while.
Order of Kilopi
Have you been reading my posts at all? That is so far wrong, it isn't even wrong. That has to come up a few notches before it starts being just wrong. Such claims are generally not worth the hard work constructing a response about just how wrong they are.
I believe my previous posts contained a scientific discussion. I notice you guys aren't talking science. You're just taking wild swings at the minority kid on the block. Tsk, tsk.
Everyone is entitled to his own opinion, but not his own facts.
Order of Kilopi
Here's some good science from a BAUT thread started by Astronomy. Post #6 in that thread talks about Halton Arp and I think succinctly and fairly describes Arp's views. Then after that description...
Maybe that's why fewer mainstreamers participate in this thread. This discussion appears to be a moot point, at least to mainstreamers.Astronomy: These observations indicate to Arp that a relationship may exist between quasars (or at least a certain type of quasar) and AGN. Arp claims that these quasars originate as very high redshift objects ejected from the nuclei of active galaxies, and gradually lose their non-cosmological redshift component as they evolve into galaxies.
The biggest problem with this analysis is that today there are tens of thousands of quasars with known redshifts discovered by various sky surveys. The vast majority of these quasars are not correlated in any way with nearby AGN. Indeed, with improved observing techniques, a number of host galaxies have been observed around quasars which indicates that those quasars at least really are at cosmological distances and are not the kind of objects Arp proposes. Arp's analysis, according to most scientists, suffers from being based on small number statistics and hunting for peculiar coincidences and odd associations. In a vast universe such as our own, peculiarities and oddities are bound to appear if one looks in enough places. Unbiased samples of sources, taken from numerous galaxy surveys of the sky show none of the proposed 'irregularities' nor any statistically significant correlations that Arp suggests exist.
Everyone is entitled to his own opinion, but not his own facts.
Established Member
Again, you have gone off topic to avoid having to present a concrete rebuttal to the bridge discussion.
Just tell us why the argument for the claimed bridge from NGC 7603 is in error. Give us a succinct summary of your arguments against this particular claimed bridge. If you can't, just say so. It is OK to say I don't know, or more data is needed. Then we can move on to the other topics such as the arguments in the thread started by Astronomy.
TomT
Established Member
You're wrong that your quote "succinctly and fairly describes Arp's views", you just dragged another red herring across the trail, it seems that as the only mainstream challenger you are clutching at straws (and still drowning).
I suggest we close the bridges discussion as being supporting evidence for Arp's model, unless the moderator has other lines of evidence/reasoning that hasn't been addressed yet, this subthread shouldn't have to take much longer. Maybe a summary can be given by Dgruss, Turbo-1 and Ari?
Cheers.
Order of Kilopi
I remember when comet Hale-Bopp came through S&T had a really neat picture of a man with his hands outstretched and cupped around Hale-Bopp. Very cool picture - but it is obvious that the man was not actually holding the comet in his hand because there is no physical phenomenon there. If there were hundreds of pictures of people holding the comet - there is still not a physical phenomenon.
But the NGC 7603 and other bridged Arpian systems are different than this example and the others you linked to. Galaxies do interact with galaxies and bridges sometimes result from those interactions. That is well established science.
So if I look at a picture like this and then place it next to a picture like this in both cases I have as a starting point an image consistent with known physical processes - that being interacting galaxies having bridges.
We must make a case for interaction or not interaction based upon additional evidence. The mainstream says one of those pieces of evidence is that the redshifts must be the same .... [sort of] it is not clear what redshift differential is to much not the same to define interaction vs. not interacting (eg B21637+290 [/sort of]. Arp says that redshifts of real interacting objects can be very different.
Since the interpretation of the redshifts in these cases is the point of difference other evidence must be sought. That is the interaction evidence we've been discussing. The evidence we've discussed RE NGC 7603 is sufficient to scientifically establish that there is a real possibility of interaction between these discordant redshift objects. Were the redshifts much closer NGC 7603 would be a mainstream poster child for interacting systems.
As I've asked before - is there any evidence (besides redshift since one interpretation cannot disprove another interpretation) that the objects are not interacting.
But we've provided very clear evidence supporting that in the case of NGC 7603 the bridge is genuine. There have been no presentations of evidence that directly contradicts the evidence we've presented in favor of interaction.I don't think anybody ever said this wasn't evidence. The question often in contention is whether the bridge is genuine, which from this distance isn't always easy to tell.
What evidence would you like to see that would constitute proof? The NGC 7603 system already has more than enough evidence to support interaction - evidence normally accepted by the mainstream.
Why is it that when the idea is ATM, the standard suddenly shifts from an idea being well supported by empirical evidence to the idea being "proven"? Is DM proven? Or is it well supported by evidence? Is DE proven? Or is it well supported by evidence? Is the BBT proven? Or is it well supported by evidence?Your approach is too modest. There is no proof of interaction, so there's no proof of intrinsic redshift.
Scientific ideas are never "proven" - just supported by evidence.
I agree Cougar ... if there was a glaring weakness in the evidence and arguments we've presented, those that like to attack with glee and fervor would be doing so. Since we know there are glee and fervor attackers on this board that do not allow flawed ATM ideas to go unattacked; attackers that press their advantage with loads of gleeful glee and manic fervor, it is quite fair to conclude from the absence of gleeful and fervorish counter-attack that there is not much to attack.What's to attack with glee and fervor?
The evidence is supportive of the ATM hypothesis in this case. And there is certainly no glee to be had or fervor to be stoked by acknowledging that an ATM idea has supporting evidence and can stand on that evidence as a viable scientific option. No glee at all. Such an acknowledgement of ATM viability could only be done with glum and failure.
Administrator
I will agree that we can put aside the bridges part of this discussion until someone has something new to add. We don't really have a scoring mechanism, but I think that clearly the pro-Arp side has made a case here that lately only Cougar was really trying to refute. Personally, I thought his chance alignment of comets argument was better than the pro-Arp folks gave it credit for, but their complaint that the mainstream people did not present nearly as well researched and reasoned an argument is valid.
Just briefly, the argument we were discussing here had to do with whether there was visible material showing arcs or lines from objects with two significantly different redshifts. There was a side discussion as to whether smaller galaxies orbiting around big galaxies had a biased redshift toward the red from the bigger galaxy. The current position seems to be:
- not all bridges are refuted, but some bridges are not real connections
- there seems to be a small bias of perhaps 30 km/sec in the redshifts of smaller galaxies compared to their larger companions.
Neither of these points are proven (for there is rarely proof in real science), but for now they are the state of our discussion.
Let's choose another topic, hopefully one that will encourage more mainstream participation.
Forming opinions as we speak
Order of Kilopi
And Cougar deserves thanks for continuing to battle!
It depends upon the point that he's trying to make. If the point is that chance alignments of objects projected on the sky can happen, then the point is good. But several weeks ago Cougar specifically asked us if chance alignments can happen and we agreed at that time that chance alignments are possible. I can find the posts if needed. That is why I think Turbo-1 is correct when he says the comet images roll back the discussion.Personally, I thought his chance alignment of comets argument was better than the pro-Arp folks gave it credit for,
However, Cougar actually tries to claim that the comet pictures are comparable to the bridged galaxy pictures:
These would be ridiculous claims to make - precisely because we already know that comets are within the solar system and the other objects are not. We see the movements of the comets relative to the background stars. M-31 and the ring nebula exhibit no such proper motions. M-31 has distance estimates from a number of methods. And finally there is no physical basis for comets interacting with galaxies and creating tails as a result of those interactions.
This argument being made by Cougar is essentially the creation of a straw man argument that trivializes the good arguments we've made which as you've noted
The point is that galaxies can interact with galaxies to produce bridges. Comets cannot. To compare images of the two phenomenon and then use that as an argument against what we've presented is a non-sequiter. We've presented additional evidence arguments that go well beyond the "looks like" arguments that the comet pictures would theoretically address. The only basis for disputing the apparent galaxy interactions we've argued for that has been provided by the mainstream is the discordant redshifts.
Agreed. The fact that we've rolled back to comet pictures reminds me of Nereid's vomited galaxy and suggests it is definitely time to move on. These sorts of trivializing arguments have been superceded by the evidence we presented in this bridges discussion. If there is nothing more rigorous and substantive to be argued against what we've presented then it is definitely time to move forward. Thanks for doing a great job of keeping the discussion on bridges focused during the last 6 weeks!Let's choose another topic, hopefully one that will encourage more mainstream participation.
Order of Kilopi
Let me say this about NGC 7603. As Lopez-Corredoira and Gutierrez state, "As far as we are aware, this is the most impressive case of a system of anomalous redshifts discovered so far." And they are probably right about that. If this is a chance alignment between a foreground galaxy with a tidal tail (at z=.029) and a background galaxy (at z=.057), then it is a chance alignment that really makes it look like the smaller galaxy pulled out that tidal tail in a previous interaction with NGC 7603.
However, the first point that seems a little odd about this scenario is the fact that the tidal tail has a redshift essentially the same as NGC 7603 all the way along its length (as reported by Lopez-Corredoira and Gutierrez). Wouldn't we expect the redshift of the tail as it nears the smaller galaxy to approach the redshift of the smaller galaxy? As I recall, DGRuss gave an explanation why the tail has a constant redshift all the way up to the smaller galaxy, where the redshift suddenly shifts another .027. But the fact that an explanation is needed at all is a bit troublesome, endowing the explanation with somewhat of an ad hoc quality.
In the end, I cannot currently prove that these galaxies did not interact in the past. As Arpians gleefully point out, there is visual and other circumstantial evidence that makes it appear that they did. I will not discount that evidence, nor will I agree that it allows us to close the case on the matter. Perhaps they did interact and there is a mundane explanation for the redshift difference. Perhaps it's a really good chance alignment, but a chance alignment nonetheless. I don't know.
Then we have the two much higher redshift "knots" that appear to be within the tidal tail between the two galaxies. With reported redshifts of z=.24 and z=.39, these objects open an entirely different discussion altogether. These are identified by Lopez-Corredoira and Gutierrez as "HII galaxies" with very vigorous star formation. If they are galaxies, they obviously appear much smaller than the two larger galaxies discussed above. Still, their positioning right in line with the tidal tail of NGC 7603 is quite a coincidence, which calls into question whether they really are embedded in the tail or deep background objects as their redshifts imply.
However, there is a somewhat mundane explanation for their high redshifts relative to NGC 7603 and its tidal tail. I don't know if this can explain the full differential, but as this apparently pro-Arp site explains, the two knots of vigorous star formation can produce bubbles of expanding ionized gas resulting from supernovae explosions, and the surface of these bubbles, an expanding shockwave of gas and dust, can be expanding quite rapidly. As the site's explanation continues, "The light emitted by the front of the bubble, in the direction of the observer is [relatively] blue shifted [into the visible spectrum]. The light emitted by the back front is red shifted [into the infrared part of the spectrum]." Further, "we can [hypothetically] find a spectral line in the visible light... and a infrared spectral line in the back Front."
However, "it is very likely considering the distance, the light emitted by the bubble is likely to have to cross clouds of gas and\or dust. The spectral line of the front "emitted" in the visible light is strongly or totally absorbed. On the other hand the spectral line "emitted" in the infrared, little absorbed, reaches the observer."
Well, if I'm reading this correctly, there may be some question whether the reported redshifts of these objects are the actual redshifts of the HII objects themselves or the redshifts of the far sides of the expanding supernova bubbles that the objects are generating, which can be moving away from us at high velocities.
I call this an "apparently pro-Arp site" because of its final conclusion, which I believe is the result of a wrong turn in the argument. As related, Arp lodged an objection to the above scenario: "The characteristic spectral absorption lines of the dust should be detected, but it is not the case." If anyone recalls, this is exactly the type of data I've been suggesting as a more sure indicator of whether objects in apparent proximity are actually close or whether they're separated by a vast expanse of space along our line of sight. Spectral absorption lines. When I asked about this type of data, the consensus of the board's Arpians seemed to be that such data didn't exist for the separate close proximity objects we've been discussing.
So I'd like to see the absorption lines, or lack thereof, of where the dust lines should be in the infrared spectrum of the far side of the receding supernova shock front that enables Arp to state, "It is not the case."
In addition, as the same site stated, "The spectral line of the front "emitted" in the visible light is strongly or totally absorbed. On the other hand the spectral line "emitted" in the infrared, little absorbed, reaches the observer." If little is absorbed in the infrared, what strength of absorption lines do we expect to see in the spectrum of the far side emission?
Of course they were ridiculous. They were obviously sarcastic examples. My point was, as VanderL was the only one bold enough to admit....
Cougar: Do you deny there is evidence for interaction...?
VanderL: Yes and no.
That's the correct answer. You cannot deny there is such evidence, but as everyone else so gleefully pointed out there was plenty of other evidence that completely ruled out any interaction scenario. But allow me to point out with fervor, that that's totally irrelevant to the point I was making, namely: There is apparent evidence for interaction. This point, by the way, is very close to the sum total of the assertions that the Arp supporters have successfully put forward over the last 10 pages of this thread.
Everyone is entitled to his own opinion, but not his own facts.
Order of Kilopi
The key question is - on what basis would we expect there to be a gradual transition of redshift in the bridge from the redshift of the parent galaxy to the redshift of the companion galaxy?
Mainstream astronomers always get wrapped up in this notion that there should be a gradual transition. But that comes from a misunderstanding of what Arp is proposing. I've answered this specific point at least 3-5 times already over the course of this thread.
Arp's hypothesis is that the redshift has an age component such that younger objects have larger redshift. If there was a gradual transition of redshift along the bridge -that would in Arp's model imply a gradual change from older to younger material. What is really expected is that the redshift of the bridge will either be the same redshift as the parent galaxy or the same redshift as the companion object. In the NGC 7603 case the redshift is the same as the parent galaxy implying that the bridge is material dragged out from the disk of the parent. In the NEQ3 case, the bridge has the same redshift as the companions indicating that the bridge is material ejected with or left behind by the companions as they moved away from the parent.
What is troubling for all of us - is that a new explanation is probably needed to account for the phenomenon - the controversial "intrinsic redshift" hypothesis.But the fact that an explanation is needed at all is a bit troublesome, endowing the explanation with somewhat of an ad hoc quality.
Very fair summary Cougar. Thanks. The only thing I'll emphasize again is that nobody is asking the case be closed.In the end, I cannot currently prove that these galaxies did not interact in the past. As Arpians gleefully point out, there is visual and other circumstantial evidence that makes it appear that they did. I will not discount that evidence, nor will I agree that it allows us to close the case on the matter. Perhaps they did interact and there is a mundane explanation for the redshift difference. Perhaps it's a really good chance alignment, but a chance alignment nonetheless. I don't know.
Another very fair summary!Then we have the two much higher redshift "knots" that appear to be within the tidal tail between the two galaxies. With reported redshifts of z=.24 and z=.39, these objects open an entirely different discussion altogether. These are identified by Lopez-Corredoira and Gutierrez as "HII galaxies" with very vigorous star formation. If they are galaxies, they obviously appear much smaller than the two larger galaxies discussed above. Still, their positioning right in line with the tidal tail of NGC 7603 is quite a coincidence, which calls into question whether they really are embedded in the tail or deep background objects as their redshifts imply.
Interesting. Certainly this is a testable proposal, but the mechanism would have to be able to explain differences of 10's of thousands of km/sec.However, there is a somewhat mundane explanation for their high redshifts relative to NGC 7603 and its tidal tail. I don't know if this can explain the full differential, but as this apparently pro-Arp site explains, the two knots of vigorous star formation can produce bubbles of expanding ionized gas resulting from supernovae explosions, and the surface of these bubbles, an expanding shockwave of gas and dust, can be expanding quite rapidly. As the site's explanation continues, "The light emitted by the front of the bubble, in the direction of the observer is [relatively] blue shifted [into the visible spectrum]. The light emitted by the back front is red shifted [into the infrared part of the spectrum]." Further, "we can [hypothetically] find a spectral line in the visible light... and a infrared spectral line in the back Front."
However, "it is very likely considering the distance, the light emitted by the bubble is likely to have to cross clouds of gas and\or dust. The spectral line of the front "emitted" in the visible light is strongly or totally absorbed. On the other hand the spectral line "emitted" in the infrared, little absorbed, reaches the observer."
Well, if I'm reading this correctly, there may be some question whether the reported redshifts of these objects are the actual redshifts of the HII objects themselves or the redshifts of the far sides of the expanding supernova bubbles that the objects are generating, which can be moving away from us at high velocities.
But if the objects are embedded in the bridge - as Arp et al propose, there will be absorbing material of the bridge between the HII galaxies and our detectors. So the presence of lower z absorption would not prove the HII galaxies are background. In Arp's scenario, there should still be absorption.I've been suggesting as a more sure indicator of whether objects in apparent proximity are actually close or whether they're separated by a vast expanse of space along our line of sight. Spectral absorption lines. When I asked about this type of data, the consensus of the board's Arpians seemed to be that such data didn't exist for the separate close proximity objects we've been discussing.
Obviously they were. But presenting unphysical examples does not provide an argument against the cases we've been debating.Of course they were ridiculous. They were obviously sarcastic examples.
I disagree that there was any evidence for interaction whatsoever. There was photographic evidence that the tails of the comets temporarily pointed toward certain objects or passed over them. But wait a few hours and those alignments are gone because of the movements of the comets.My point was, as VanderL was the only one bold enough to admit....
Cougar: Do you deny there is evidence for interaction...?
VanderL: Yes and no.
That's the correct answer. You cannot deny there is such evidence,
In the case of NGC 7603 the bridge has been photographed repeatedly with multiple instruments over multiple decades. It is there and it is a feature that is observed in interacting systems. It is evidence for interaction. If the bridge was only imaged once and was not present in subsequent image then the one image that showed the bridge would not be evidence for interaction.
That was the point of the bridges discussion. If there is evidence for interaction, then there is evidence the redshift anomalies are real. The more evidence for interaction that accumulates, the stronger the evidence for the discordant redshift.but as everyone else so gleefully pointed out there was plenty of other evidence that completely ruled out any interaction scenario. But allow me to point out with fervor, that that's totally irrelevant to the point I was making, namely: There is apparent evidence for interaction. This point, by the way, is very close to the sum total of the assertions that the Arp supporters have successfully put forward over the last 10 pages of this thread.
You're argument here makes it seem as if the evidence we've discussed provides a case for interaction no stronger than the non-existent evidence in the comet images. That's just not a reasonable comparison.
Established Member
Cougar,
Much of what you said regarding the pros and cons of the NGC 7603 case is good stuff. I do want to differ with the above statement by you, with emphasis on the phrase "very close" (or even close at all). You showed us a picture of a comet with a tail that essentially engulfed the backgroud galaxy, and extended past it. This in no way is very close, or even remotely close to the optical images of bridges claimed by Arp supporters. And in cases of claimed bridges, Arp et al, draw on any of the available supporting evidence to bolster their claims. Anyway, you did some homework in your discussion of the 2 objects seen in the tail emanating from NGC 7603, and this type of discussion is welcome. I believe drguss23 gave a reasonable reply on this.
TomT
Established Member
Hi All,
I refer to the above quote, not to pick on Cougar at all, but to relay a pet peeve of mine. I think this discussion has reached a pretty high level as far as most of these ATM threads have gone. I would like to see it reach a high enough level that we don't need to talk about glee, as in cheerleaders rooting for one side or another. However, I think fervor is good. I am here to seriously seek the facts as best we can. I think this group has the potential to become a serious research team, with proponents of both sides working for a positive mutual goal of extending our knowledge of the truth, rather than two sides seeking to only defend our home teams.
Can we dispense with the glee and proceed to seek the facts with fervor?
TomT
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