Dancing David
Penultimate Amazing
doppo
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.Sorry about the mixup! Magnitudes are certainly backwards, and always have been!
The paper you post is interesting, but I don't have time for an in-depth look right now (at work, doing more mundane things!). I will look more this evening.
One thing that I think is interesting, is that Mountrichas and Shanks show correlation function graphs that seem to decline to beta=0 for separations of about 1-2 arcminutes.
Am I correct in taking this to mean that the correlation effects (=apparent increase in QSOs) are limited to 1-2 arcminutes from the lensing source?
Aren't a lot of Arp's "associated objects" and his constant writing about "densities of QSOs above background levels" considering areas up to 60 arcminutes from AGNs?
If you don't mind BeAChooser, where are the original articles (that these are 'some more' to)?
would you mind if ask you whether you've done some work to estimate the average areal density of QSOs?
If you haven't done such work, would you mind if I ask why the papers you cite, and the ones they, in turn, quote, have such different values for this key parameter?
Further, to what extent would you say the Burbidges included an estimate of various lensing effects, in the work they did to come at their conclusion?
Finally, how consistent would you say the various authors have been in the definitions of "QSO" that they have used?
You are, no doubt, aware that there are many 'lensed quasars' - objects which have been (strongly) lensed by foreground galaxies.
You are also, no doubt, aware that these are readily explained by assuming they are at distances implied by their redshifts and Hubble relationship (as well as mass models of the lensing galaxies that are just like local galaxies that have been studied in great detail).
'what's a quasar' (and, in this case, is it the same as a QSO)?
Care to take a stab at why the two referees were not convinced?
HINT: it's pretty obvious.
Seriously though, this paper is about as powerful and direct a refutation of Arp's original work as it is possible to imagine.
Never mind; the key question here is the same as introduced for paper one: what is a 'quasar'?
For two gold stars, try correctly answering this question: in a volume-limited survey of quasars, how complete are the 2dF and SDSS surveys, by redshift?
BAC, this paper is garbage, it should never have been accepted by ApJ for publication ... and it's extremely easy to show why.
Surely you jest BAC?!
I mean, Tomes' material isn't even published
The Scranton paper http://arxiv.org/PS_cache/astro-ph/p.../0504510v1.pdf, which seems rock solid to me
.Why don't you ask David for a complete list since he claims he's read everything I've posted.![]()
.No, I haven't. Have you?
.Could you be more specific? Which papers and how different are the values? What do you think the value is?

.There are many instances where the Burbidges talk about lensing in their papers. For example, there is this from a 1997 paper by Burbidge, Hoyle and Schneider (http://209.85.173.104/search?q=cach...ge+lensing+redshift&hl=en&ct=clnk&cd=10&gl=us ) titled "Very close pairs of quasi-stellar objects": It is pointed out that there are now known four very close pairs of QSOs with separations < 5 arcsec and very different redshifts. Several estimates indicates that the probability that they are accidental configurations are small; a conservative estimate of the probability to have four such pairs by random projection yields 3.5 × 10-3. We conclude either that this is further evidence that QSOs have significant non-cosmological redshift components, or that the pairs must be explained by gravitational lensing. ... snip ... we turn to (3) and discuss what can be said in favor of a gravitational lensing scenario ... snip ... " And both Hoyle and Burbidge conclude that lensing doesn't explain it.
.And here are quotes from a 2000 paper (http://www.iop.org/EJ/article/1538-3881/121/1/21/200276.text.html ) by Burbidge: "To a first approximation, the QSOs in this list are simply the lensed fraction of the brightest QSOs in (say) the Hewitt & Burbidge (1993) catalog, modulated by some smooth function to take account of the lensing probability (which is a function of magnitude). ... snip ... The lensing probability varies smoothly with magnitude and so is unlikely to have much effect on the calculated significance ... snip ... Even among the gravitational lens candidates, there are only 12 in which it is claimed that the lensing galaxy has been identified and its redshift measured (Véron-Cetty & Véron 2000, Table*5)." So it looks like he was still considering lensing in 2000.
.In fact, the 2000 book "A Different Approach to Cosmology" by Hoyle, Burbidge and Narlikar has quite a lot to say about lensing ... including this: "The theory of gravitational lensing tells us that there is a small probability that the image of a background QSO at its redshift distance will be amplified by gravitational lensing due to a halo object so that it will appear much brighter than it actually is. If this mechanism is to explain the apparent associations of QSOs and galaxies, all of the spiral galaxies and also galaxies of other types must have these extended dark matter halos; but more important, a very large density of QSOs fainter than 20m must be present so that there are always enough QSOs in the field to explain the number of close associations. Now we have a very good data on the density of QSOs on the sky. ... snip ... Using this, it has been shown by several authors 35,36 that this mechanism will not explain the observed effect essentially because the density on the sky of QSOs begins to flatten off as the QSOs get fainter (>21m)." Have you by chance read it?
So yes, I'd estimate that Burbidge has considered lensing effects in his work.
.No idea. Again, do you have an example of inconsistency in the definition you'd like to highlight?
.How many? What percentage of the total? Has Burbidge misidentified or overlooked one in his work that you'd like to point out?
.Not everyone appears to agree with that. Are you aware of this?
http://209.85.173.104/search?q=cach...ge+lensing+redshift&hl=en&ct=clnk&cd=15&gl=us "QSO-Galaxy Association and Gravitational Lensing, S. M. Tang and S. N. Zhang, 2005 ... snip ... NGC 3628 is a well-studied nearby edge-on Sbc peculiar galaxy, where QSOs are shown to be concentrated around the galaxy with a density much higher than background. We show that if present understanding of the luminosity function of QSOs is right, such concentration could not be caused by gravitational lensing."
.I'd hazard that the answer is yes. Why do you ask?
.If you have something to say ... just say it. No need to be coy.
.And in what way is it that? Again, if you have something to say ... then just say it, DRD. No need to be coy. Until you do, I'll just let what I quoted from Lopez-Corredoira and C. M. Gutierrez paper speak for itself.
.Again, no need to be coy. If you think the definition that Arp, et al, have used is wrong or inconsistent, then just say so and tell us why.
And for three gold stars, tell us why this is important in relation to the various papers by Arp, Burbidge, etc.![]()
.But it was accepted. So why don't you just spare us ALL your coyness and tell us why exactly that paper is garbage. And if you happen to be able to cite some letter to a journal or another peer reviewed paper to back up what you so, so much the better. No need to keep us in suspense.
.No, I don't jest. That looks like a perfectly reasonable argument.

.So what? One of the challenges I've repeatedly given your side of this debate is to provide published articles that challenge the many published articles I've provided. And the silence has been golden. To be quite frank, DRD, your side doesn't seem to think it matters whether a criticism of a theory is published or not.![]()
.How many times have we heard that.![]()
One reason I'm skeptical that it's "rock solid" is that it doesn't even mention Arp, Burbidge or any of the other researchers that have been the primary critics of the mainstream on this issue. Don't you find that a little strange?
.Perhaps their failure to mention Arp, et. al. is because they don't want to lead their readers to their opponents papers and books ... where they might learn there is more to this story than what this "rock solid" paper suggests.
You see, in particular, I guess I'd like an explanation how this explains the apparent over-density of quasars and high redshift galaxies along the minor axes of low redshift galaxies, as well as the over-density with relation to certain other features of galaxies like jets and x-ray lobes. The paper doesn't speak to that. At least, I couldn't find any mention of minor axes or jets.
.You see, I'd have less problem with Scranton's explanation if the quasars near galaxies were distributed in a uniform manner ... in accordance with the supposed spherical halo distribution of dark matter. But that doesn't appear to be the case as paper after paper by Arp and others that I've cited clearly show. Also, surely you aren't suggesting "lensing" explains the highly unlikely alignment in NGC 7603 where we see galaxies of quite different redshifts precisely aligned along a low redshift filament and apparently interacting with that filament.
.So do you care to comment?
Talk about coy.Why don't you ask David for a complete list since he claims he's read everything I've posted.![]()
Your papers, old man.. would you like a cigarette? Perhaps this one?No, I haven't. Have you?
Could you be more specific? Which papers and how different are the values? What do you think the value is?
Ah, yes but is it consistent with the more recent work?There are many instances where the Burbidges talk about lensing in their papers. For example, there is this from a 1997 paper by Burbidge, Hoyle and Schneider (http://209.85.173.104/search?q=cach...ge+lensing+redshift&hl=en&ct=clnk&cd=10&gl=us ) titled "Very close pairs of quasi-stellar objects": It is pointed out that there are now known four very close pairs of QSOs with separations < 5 arcsec and very different redshifts. Several estimates indicates that the probability that they are accidental configurations are small; a conservative estimate of the probability to have four such pairs by random projection yields 3.5 × 10-3. We conclude either that this is further evidence that QSOs have significant non-cosmological redshift components, or that the pairs must be explained by gravitational lensing. ... snip ... we turn to (3) and discuss what can be said in favor of a gravitational lensing scenario ... snip ... " And both Hoyle and Burbidge conclude that lensing doesn't explain it.
And here are quotes from a 2000 paper (http://www.iop.org/EJ/article/1538-3881/121/1/21/200276.text.html ) by Burbidge: "To a first approximation, the QSOs in this list are simply the lensed fraction of the brightest QSOs in (say) the Hewitt & Burbidge (1993) catalog, modulated by some smooth function to take account of the lensing probability (which is a function of magnitude). ... snip ... The lensing probability varies smoothly with magnitude and so is unlikely to have much effect on the calculated significance ... snip ... Even among the gravitational lens candidates, there are only 12 in which it is claimed that the lensing galaxy has been identified and its redshift measured (Véron-Cetty & Véron 2000, Table*5)." So it looks like he was still considering lensing in 2000.
In fact, the 2000 book "A Different Approach to Cosmology" by Hoyle, Burbidge and Narlikar has quite a lot to say about lensing ... including this: "The theory of gravitational lensing tells us that there is a small probability that the image of a background QSO at its redshift distance will be amplified by gravitational lensing due to a halo object so that it will appear much brighter than it actually is. If this mechanism is to explain the apparent associations of QSOs and galaxies, all of the spiral galaxies and also galaxies of other types must have these extended dark matter halos; but more important, a very large density of QSOs fainter than 20m must be present so that there are always enough QSOs in the field to explain the number of close associations. Now we have a very good data on the density of QSOs on the sky. ... snip ... Using this, it has been shown by several authors 35,36 that this mechanism will not explain the observed effect essentially because the density on the sky of QSOs begins to flatten off as the QSOs get fainter (>21m)." Have you by chance read it?
So yes, I'd estimate that Burbidge has considered lensing effects in his work.
Ah, so what is an AGN and how theoretically does the alignment of the AGN perhaps correlate with QSOs?No idea. Again, do you have an example of inconsistency in the definition you'd like to highlight?
Oh, oh, you ar egtting flustered, the same probing questions that you supposedly ask of the standard model and you get flustered.How many? What percentage of the total? Has Burbidge misidentified or overlooked one in his work that you'd like to point out?
Now tie them together BAC, how does the weak lensing, the angle effect and clutering of galaxies and QSOs all have a relation to the paper you cite?Not everyone appears to agree with that. Are you aware of this?
http://209.85.173.104/search?q=cach...ge+lensing+redshift&hl=en&ct=clnk&cd=15&gl=us "QSO-Galaxy Association and Gravitational Lensing, S. M. Tang and S. N. Zhang, 2005 ... snip ... NGC 3628 is a well-studied nearby edge-on Sbc peculiar galaxy, where QSOs are shown to be concentrated around the galaxy with a density much higher than background. We show that if present understanding of the luminosity function of QSOs is right, such concentration could not be caused by gravitational lensing."
Ah, that is classic BAC, you are coy and obtuse, vague and opaque, you deny what you have said and then you ask someone to come right out with an answer.I'd hazard that the answer is yes. Why do you ask?
If you have something to say ... just say it. No need to be coy.
One reason I'm skeptical that it's "rock solid" is that it doesn't even mention Arp, Burbidge or any of the other researchers that have been the primary critics of the mainstream on this issue. Don't you find that a little strange?
You see, in particular, I guess I'd like an explanation how this explains the apparent over-density of quasars and high redshift galaxies along the minor axes of low redshift galaxies, as well as the over-density with relation to certain other features of galaxies like jets and x-ray lobes. The paper doesn't speak to that. At least, I couldn't find any mention of minor axes or jets.
You see, I'd have less problem with Scranton's explanation if the quasars near galaxies were distributed in a uniform manner ... in accordance with the supposed spherical halo distribution of dark matter. But that doesn't appear to be the case as paper after paper by Arp and others that I've cited clearly show. Also, surely you aren't suggesting "lensing" explains the highly unlikely alignment in NGC 7603 where we see galaxies of quite different redshifts precisely aligned along a low redshift filament and apparently interacting with that filament.
So do you care to comment?
What do you think of this Mountrichas and Shanks paper?
.I noticed another Shanks paper here: http://arxiv.org/abs/astro-ph/0609339v2
Seems like he might be investigating the need for dark energy by looking at these lensing issues.
The Sloan Digital Sky Survey Quasar Lens Search. III. Constraints on Dark Energy from the Third Data Release Quasar Lens Catalog
We present cosmological results from the statistics of lensed quasars in the Sloan Digital Sky Survey (SDSS) Quasar Lens Search. By taking proper account of the selection function, we compute the expected number of quasars lensed by early-type galaxies and their image separation distribution assuming a flat universe, which is then compared with seven lenses found in the SDSS Data Release 3 to derive constraints on dark energy under strictly controlled criteria. For a cosmological constant model (w = -1) we obtain ΩΛ = 0.74+0.11 -0.15(stat.)+0.13 -0.06(syst.). Allowing w to be a free parameter we find ΩM = 0.26+0.07 -0.06(stat.)+0.03 -0.05(syst.) and w = -1.1 ± 0.6(stat.)+0.3 -0.5(syst.) when combined with the constraint from the measurement of baryon acoustic oscillations in the SDSS luminous red galaxy sample. Our results are in good agreement with earlier lensing constraints obtained using radio lenses, and provide additional confirmation of the presence of dark energy consistent with a cosmological constant, derived independently of type Ia supernovae.
You were the one who mentioned them, so I thought you'd be the best source.
Oh, and yes, I have and I did ... otherwise I wouldn't have had to guts to write anything
BAC, the papers you yourself cited!!!!
And are those estimates consistent with other Burbidge (and Arp) papers?
however, my question was whether or not lensing had been considered in the B&B paper you cited
Omigod, omigod ... you've supposedly read all these papers on how QSOs/quasars may not (all) be at cosmological distances, published over a period of several decades, and not once, in all your reading, have you grokked that 'what is a quasar?' might, just might, be important to why there's so much fuss?
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How many? What percentage of the total? Has Burbidge misidentified or overlooked one in his work that you'd like to point out?
Oh dear, you mean you don't actually know?!?
You might try CASTLES for starters (be sure to actually read, critically, the various papers on the publications page).
in a later post I'll cite a paper or two which reports some of these estimates; I do hope you're still around then,
http://209.85.173.104/search?q=cache...nk&cd=15&gl=us "QSO-Galaxy Association and Gravitational Lensing, S. M. Tang and S. N. Zhang, 2005 ... snip ... NGC 3628 is a well-studied nearby edge-on Sbc peculiar galaxy, where QSOs are shown to be concentrated around the galaxy with a density much higher than background. We show that if present understanding of the luminosity function of QSOs is right, such concentration could not be caused by gravitational lensing."
So, a battle of really cool abstracts, right?
Try this one for size then
Um, er, because consistent use of these two terms is central to the point you seem to be trying, rather in vain, to make?
You cite a paper by a fave author (Arp, in this case), and include a note that it was rejected by two referees ... and you have no interest in trying to find out why they rejected it?
I can well understand why others have called you a troll.
why should anyone waste their time on replying to you?
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Again, if you have something to say ... then just say it, DRD. No need to be coy. Until you do, I'll just let what I quoted from Lopez-Corredoira and C. M. Gutierrez paper speak for itself.
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In other words, you haven't a clue about what either this paper or the 'landmark' Arp one(s) actually say.
For the benefit of others who read this thread, at a later date I'll go over some of the reasons L-C&G's paper does a wonderful job of demolishing Arp.
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Again, no need to be coy. If you think the definition that Arp, et al, have used is wrong or inconsistent, then just say so and tell us why.
And for three gold stars, tell us why this is important in relation to the various papers by Arp, Burbidge, etc.
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Oh wow, I haven't had so much fun in ages!!!
What, BAC, do you think the key thing in all (but one) of the materials you cited is?
It's the number of quasars (or QSOs) in each square degree
I said I'd give you two days, and I shall.
Whatever happened to critical thinking BAC? Independent verification? Checking of sources and logic? You mean to say all you did was read the words and conclude it "looks like a perfectly reasonable argument"?!?!?!
Well, this is the first time I've actually responded to anything you wrote in direct response to what I wrote
Here's a clue for you BAC: few professional astronomers bother even reading papers by Arp et al. these days (unless they are asked to review them). There are many reasons why they don't; one of them is that these guys (and one gal) have such an appallingly bad record of even understanding the issues (such as statistics) much less writing anything of value (though some papers are good for teaching purposes - 'find a minimum of five fatal flaws in this paper', for example - and others worthy objects for derision over coffee).
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You see, in particular, I guess I'd like an explanation how this explains the apparent over-density of quasars and high redshift galaxies along the minor axes of low redshift galaxies, as well as the over-density with relation to certain other features of galaxies like jets and x-ray lobes. The paper doesn't speak to that. At least, I couldn't find any mention of minor axes or jets.
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Well, considering that the best 'alternative' is, in fact, a powerful rebuttal of many of Arp's early papers, perhaps the explanation is a lot simpler than this fervid conspiracy theory based suggestion?
Oh so now we shift from the main point of Scranton et al. (lensing of background quasars by foreground galaxies) to precise alignment of galaxies in a filament?
You want to cite the NGC 7603 paper now perhaps?
Oh, and precisely aligned? to within <0.0000000000001 arc-seconds??
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So do you care to comment?
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Yep; just did.
Like I said, David should have no trouble linking you to them. Or you could use your browser and check the few threads I've posted on here at JREF where the Big Bang or modern astrophysics has been discussed. I just don't care to repeat everything for the Nth time.
Well again, don't be coy. I don't see anywhere on this thread where you've offered that data yet. Waiting...
I've cited lots of papers. So which exact papers and which exact numbers are you worried about? Don't be coy. If you have problem with a specific number cited in one of the papers then identify it and tell us what you think it should be.
What estimate? What precise number? Don't be coy. Just tell us specifically what numbers you think are inconsistent in which two papers. Then we can discuss it.
There is no mention of lensing in the paper. B&B just note that there are 20 QSOs in a 16 deg2 region centered on NGC 5548 and that 13 of those 20 are to located in about a 1 deg2 region centered on NGC 5528. Now, go ahead and explain that away with your lensing statistics. Don't be coy.
You're still being coy. And I notice you haven't yet been anything but coy so far in this thread.
Coy. You do know what that word means, don't you? Keep it up and I may ignore you like I do David.
Before I go to all that trouble, why don't you just stop being coy and tell us exactly where Arp, Burbidge, etc have gone wrong in their definition of quasar (or QSO, if you like).
No need to be coy. Just do it now. We are all waiting.
Not quite. I actually linked you to the article so you can see the details in how they arrived at that conclusion.
That's just an abstract. Here's the full article: http://arxiv.org/pdf/0705.0446 . I note they based that conclusion on a sample of only 64 quasar-galaxy pairs out of all they had available.
Yeah, but we still don't know what you find inconsistent due to your coyness.
I didn't say I wasn't interested. In fact, I ASKED YOU to tell us why. Instead, all we get is more coyness.
At least I'm not a coy troll.
So why are you? Because you saw the rest of them were floundering in this discussion? Did you think you'd clear it up with coyness?
In other words, you'd rather be coy than actually state your concern. Like I said, until you do, I'll let what I quoted from L-C&G's paper speak for itself.
Why be so coy? Why not just do it now? ... If you really are interested in clearing up any confusion my posting L-C&G's paper might have caused.
What? Is coyness all we will get from you?
And will you ever get around to giving us that number and show us why Arp, et al, are wrong? Or just go on being coy?
Guess you'll go on being coy.
Coyness? Is that all we'll every get out of you?
Gee ... that sounds like another coy response.
More coyness. We still haven't actually heard what these flaws are, DRD.
Yes. Which they've built into complex particle in cell computer codes that model the effects of gravity, electric and magnetic effects on matter with great precision. And then they've run those codes on very big computers and proven that the electro-magnetic effects dominate and produce observed rotation curves without introducing vast additional amounts of undetectable, untestable, bizarrely propertied dark matter. You might want to look up Dr Anthony Peratt at LANL.
There is at least one paper which looks at both the SDSS and 2dF surveys: "QSO lensing magnification: a comparison of 2QZ and Sloan Digital Sky Survey results" (arXiv link - note that there are two versions, dated Jan 2007 and Feb 2008).
What do you think of this Mountrichas and Shanks paper?
Another promising thread caught in a train-wreck of egos and accusations!
Anyone have any constructive comments about the radial distance issue I mentioned before?
While the paper is a perfectly valid test of cosmic magnification, the assumptions of the paper (through some of the cuts made) simply do not allow for a comparison with Arp’s empirical model.
First, you have to recognize that Arp’s examples involve associations between specific galaxies and specific QSO’s. The vast majority of identified QSO parent galaxies are very low redshift. When a QSO parent is above z=0.1, there is likely a larger, lower redshift AGN nearby that is the parent of the QSO’s parent. For example, the NEQ3 system has a z=0.12 galaxy as the parent of several z=0.19-0.22 objects. But NEQ3 is near the much lower redshift Seyfert (again) NGC 4151.
So immediately a problem with using the magnification study as a test of Arp’s hypothesis is that the study does not attempt to find associations between AGN and the QSO’s.
A second point is that if you look at figure 1 of the paper you’ll see that the lower redshift galaxies peak around z=0.3. That is not a suitable redshift for finding QSO parent galaxies in Arp’s model. You want to focus on galaxies with z<0.1 and really galaxies with z<.05. So regardless of the correlations the study found, the galaxies used were not constrained to the appropriate redshift range for QSO parents.
A third point is that the assumption that quasars are at cosmological distances does have an impact on the validity of the analysis as a test of Arp’s model. The quasars were assumed to be background objects in order to test for the magnification signal. The first sentence of the paper:
We expect the large-scale structure seen in the low redshift Universe to gravitationally lens background objects such as high redshift galaxies and quasars.
This is the whole underlying premise of the test for magnification and it directly affects the sample selection (page 5):
In addition to finding quasars, we applied photometric redshift techniques (Weinstein et al 2004) to filter out lower redshift quasars which might be physically associated with our foreground sample. … To prevent redshift overlap with the galaxies, we required that the upper and lower bounds were within the range 1 < z < 2.2 …
So I find myself mystified as to why there is an objection to my statement that the QSO’s were assumed to be background. The paper clearly spells out that there was such an assumption for the magnification test. The quasars are described as background and redshift ranges are set such that lower redshift QSO’s are eliminated because they might be associated with the galaxies that are interpreted to be foreground.
Now don’t misunderstand. The technique and cuts were perfectly appropriate for a cosmic lensing test, but they were not appropriate for testing the local QSO’s hypothesis.