Arp objects, QSOs, Statistics

[DeiRenDopa]

Based on just two examples - in one day! - I'm wondering if I am approaching the study of why threads like this go on for so long the wrong way.

Perhaps I should be looking at things like the extent to which BeAChooser mis-represents or misunderstands his primary sources? Y'know, things like "I know that's what you quoted from the Arp et al paper BAC, but here's what that paper actually says (blah blah blah). Would you mind explaining how you came to so badly misrepresent the original?"

In one sense it's similar - what methods are used to evaluate? how to make decisions about correspondence to how the universe actually works?

 

[Dancing David]

Funny. The argument that it was dangerous for Arp to infer some physical significance from an apparent association has been repeatedly criticized by thread members on the grounds that the database being used to draw the association was not complete ... that Arp was severely undersampling the data.

Now I show a case where even if you include ALL the possible datapoints, the probability of that case turning up *by chance* is on the order of 10^-5 or smaller ... and I'm still told its dangerous to draw any conclusion.

But i don't recall you sampling all the galaxies or even a representative sample, you extrapolated from a small sample to the galaxies as a whole, did you not?

What is the total set of QSOs and how are they arranged, did you asnwer that question, did you demonstrate that you took a randomly distributed sample to derive your figures?

No you chose a numer ,30, I belive and the extrapolated it to the whole sky.

If I recall correctly.

If you did that to prove your case in court then the other side would win. If you want to do things that way then you need to sample different araes to determine what the actaul density is, and not just extrapolate it to the whole sky. You can then talk about the confidence intervals that you samples are representative of the sky.

In populations and especially when you are trying to show an association in a sub population, you need to have representative samples and the normative statistics. If you do it that the way you are doing it, medical statistics would not produce the life style and heart disease correlations that are used to advise people to reduce thier risk of heart attack.

And I'm advised this even though there are other cases where there seems to be an unlikely frequency of redshifts close to the quantized values initially predicted by Karlsson. Take for example NGC 5985 where there are again 5 x-ray emitters near a galaxy that are lined up along a minor axis with redshifts of 2.13, 1.97, 0.59, 0.81 and 0.35. The probability of that occurrence, even on a combinatorial basis, is 7 x 10^-6 (compared to the earlier 5.8 x 10^-8). So that would make the final probability of this case, taking all the other factors I added in the other case into account, about 10^-3.

And what is the chance of being dealt a royal flusk hearts in a hand of poker, astronomical, right?

You are not reading at all on population samplaing are you?


You are again assuming that all those factors are evenly represented and that they are evenly distributed.

the burden of proof is on you to show that the density figures and relationships you use are not just statistical coincidence.

that is standard practice for the person alleging a correlation.

More later.

But the two cases aren't independent. Finding one case makes the probability of finding the other case even smaller. And these aren't the only cases.

Consider NGC 3628

http://www.eitgaastra.nl/pl/f54a.gif

which has 3 quasars at z = 1.94, 2.43 and 0.408 at the base of the east-north-east plume, coincident with the start of an optical jet, three more quasars in the southern plume along the minor axis at z = 0.995, 2.15. 1.75, plus two more quasars, with z = 2.06 and 1.46, aligned along what looks to be the opposite side major axis.

All told there 8 high redshift, x-ray emitting objects, aligned along specific features related to a low redshift z = 0.0028 galaxy, that have redshifts suspiciously close to Karlsson's predicted values of z = .06, .30, .60, .96, 1.41, 1.96, and 2.64. What are the chances of that again occurring just by accident? And because you have to draw this case from the same limited group of clusterings around galaxies in the total sample, this low probability forces the others to be even lower.

And of course that's not the last case either.



First of all, <5% is not rare in the sense that the cases I've noted above are rare. We are talking many orders of magnitude difference in probability. Night and day.



Actually, I don't think that's true at all. Just consider the number of galaxies that are out there compared to the number of identified quasars. And you don't have to align 6 of them up with 1 galaxy ... just one.

QSOs ... ~50,000.

But in 1999 the Hubble Space Telescope team estimated 125 BILLION galaxies in the observable universe. And with a new camera, they recently observed twice as many as before. Now if even 1% of galaxies has its major axis aligned with our viewing angle, that leaves 2 BILLION galaxies. Plus, they are a pretty noticable object. You see one in a field and it stands out ... unlike a quasar. So no, I don't think it is at all improbable that they found a ring galaxy within a ring galaxy.

 

[BeAChooser]

There seem to be two different ideas at play, the improbability of a certain configuration of objects ('quasars'), and a patern in observed (quasar) redshift distribution(s).

Taking the first one for this post.

Improbable things happen all the time - someone wins a lottery, for example, or some highly unlikely combination of circumstances leads to an unfortunate accident.

True. But that doesn't rule out the possibility that the two phenomena are connected ... especially if it turns out the high redshift x-ray emitting object near galaxies are improbably quantized and distributed in a pattern matching the theory that Arp, Narlikar, et al have proposed for their origin and behavior.

So what's the probability that you can find some really cool configuration ('alignment') of stars across/around a galaxy? If you go looking for such a configuration, without first stating what it is you are looking for, it's almost certain you will find one!

But in the case of the curious redshift quantization examples I've listed, the predicted redshift quantization values were defined before those specific cases were found and studied by Arp. So your objection doesn't appear to apply in this case. So let's deal with this case rather than just waving hands ... Fair enough?

 

[BeAChooser]

Originally Posted by BeAChooser
Sure, as long as I get to observe that the way you went about evaluating that study was to immediately rule it out simply because it used a source where the author hedged their bets saying *don't use this because it's incomplete*.

Originally Posted by DeiRenDopa
... snip ... Do you mind if I ask you to be more careful in how you quote, BeAChooser?

"And just because Bell used a source that said it wasn't a complete list of all objects doesn't necessarily invalidate the results." - those are words you wrote, not me.

Oh ... did I misinterpret your reasons for dismissing Bell when you quoted the source he cited saying "This catalogue should not be used for any statistical analysis as it is not complete in any sense, except that it is, we hope, a complete survey of the literature." and then said "As I said, earlier in this thread, this Bell paper is garbage, and should never have been published in ApJ."? Looks to me like you had only one reason ... that the data Bell used was in a source that made that statement ... which you even highlighted to draw our attention to it.

 

[BeAChooser]

To other readers: I'm curious to know what you think about the acceptability of the approach BeAChooser's comment implies, in (extra-galactic) astronomical research.

To other readers ... let's see what DRD has to say about that calculation I did with respect to the probability of NGC 3516, NGC 5985 and NGC 3628 just being chance occurrences. Let's see if he actually deals with the numbers and probabilities ... or just hand-waves it away like David tried to do.

Specifically, if the authors of a catalogue explicitly state their catalogue should not be used for statistical analyses, and someone proceeds to do just that, what degree of credibility do you think should be given to that someone's paper?

Well let's take a closer look at VCVcat (a.k.a. Véron-Cetty, M.P. and Véron, P. 2006, A&A, 455, 773), which is what Bell used. That would be this: http://adsabs.harvard.edu/cgi-bin/bib_query?2006A&A...455..773V whose abstract states "This catalogue is aimed at presenting a compilation of all known AGN in a compact and convenient form and we hope that it will be useful to all workers in this field. ... snip ... The present version contains 85 221 quasars, 1122 BL Lac objects and 21 737 active galaxies (including 9628 Seyfert 1s), almost doubling the number listed in the 11th edition. We also give a list of all known lensed and double quasars." I don't know, DRD ... that looks pretty complete to me.

And if "workers in this field" aren't supposed to use what would appear to be one of the more complete databases, tell us what are they supposed to use? Note that this NASA site: http://heasarc.gsfc.nasa.gov/W3Browse/all/veroncat.html fails to mention the disclaimer that you quoted. Don't tell me NASA is using the data without regard to the disclaimer. Oh my!

And are there others using this data base or an earlier version of the catalog? Yes. See these:

http://arxiv.org/pdf/astro-ph/0611820.pdf "Photometric Selection of QSO Candidates From GALEX Sources, David W. Atlee
and Andrew Gould, 2007"

http://www.journals.uchicago.edu/doi/abs/10.1086/379006 "On the Cross-Correlation between the Arrival Direction of Ultra–High-Energy Cosmic Rays, BL Lacertae Objects, and EGRET Detections: A New Way to Identify EGRET Sources?, Diego*F.*Torres, Stephen*Reucroft, Olaf*Reimer, Luis*A.*Anchordoqui, 2005"

http://aps.arxiv.org/pdf/astro-ph/0703280 "Quantum Vacuum and a Matter - Antimatter Cosmology, Frederick Rothwarf and Sisir Roy, 2006"

http://www.auger.org/technical_info/pdfs/icrc2007/0706.1715v1.pdf "Search for correlation of UHECRs and BL Lacs in Pierre Auger Observatory data, Diego Harari, 2007"

http://www3.interscience.wiley.com/cgi-bin/abstract/113489988/ABSTRACT?CRETRY=1&SRETRY=0 "Automated spectral and timing analysis of AGNs, F. Munz, V. Karas, M. Guainazzi, 2006"

http://www.saber.ula.ve/db/ssaber/Edocs/centros_investigacion/cat/publicaciones/papers/isamp.pdf "Dynamic multiple scattering, frequency shift and possible effects on quasars astronomy, Sisir Roy, Malabika Roy, Joydip Ghosh, Menas Kafatos, 2007"

http://209.85.173.104/search?q=cach...tatistical+analysis&hl=en&ct=clnk&cd=27&gl=us "A Bar Fuels a Super-Massive Black Hole?: Host Galaxies of Narrow-Line Seyfert 1 Galaxies, Kouji Ohta, Kentaro Aoki, Toshihiro Kawaguchi and Gaku Kiuchi, 2006"

https://ritdml.rit.edu/dspace/bitstream/1850/1788/1/SBaumArticle11-2004.pdf "The host galaxies of luminous quasars, David J. E. Floyd, Marek J. Kukula, James S. Dunlop, Ross J. McLure, Lance Miller, Will J. Percival, Stefi A. Baum and Christopher P. O’Dea, 2006"

And I could go on. It appears almost no one is heeding that warning, DRD. So are all of the above apriori "garbage" or do scientists tend to use whatever data they can get their hands on and ignore the lawyerly legalize sometimes added by bureaucrats even to what would appear to be one on of the most complete databases available at the time?

 

[BeAChooser]

Apart from the 'areal density' logic chain, and the 'alignment of a jet' one (the latter is a pretty darn good example of a posterori logic

I'm curious, DRD. Is the only case you will accept one where Arp, et al, predict before the fact there will be a quasar in front of a galaxy with what appears to be a jet coming from the nuclear toward it. They have to make the prediction before even looking at the galaxy otherwise that data can be dismissed? Is that the logic you work by? Because if it is, I hate to tell you how many claims of proof in their theory that Big Bang proponents have made by looking at observations that were not predicted at all ... even contrary to what actually was predicted. Frankly, I think what you're now engaging in is hand-waving ... ala David.

Of course, spiral arms are not optically thick, not even in the x-ray band, as W. Kell has shown in a series of papers, and as this Chandra PR attests (work based on discovery of a hole by Lockman et al.).

Care to show us ANY evidence of ANY object behind the galaxy being seen through that region of the galaxy? Or are you just waving your hands?

 

[BeAChooser]

Originally Posted by BeAChooser
Now I show a case where even if you include ALL the possible datapoints, the probability of that case turning up *by chance* is on the order of 10-5 or smaller ... and I'm still told its dangerous to draw any conclusion.

And I'm advised this even though there are other cases where there seems to be an unlikely frequency of redshifts close to the quantized values initially predicted by Karlsson. Take for example NGC 5985 where there are again 5 x-ray emitters near a galaxy that are lined up along a minor axis with redshifts of 2.13, 1.97, 0.59, 0.81 and 0.35. The probability of that occurrence, even on a combinatorial basis, is 7 x 10-6 (compared to the earlier 5.8 x 10-8). So that would make the final probability of this case, taking all the other factors I added in the other case into account, about 10-3.

But the two cases aren't independent. Finding one case makes the probability of finding the other case even smaller. And these aren't the only cases.

(rest of post omitted)
.

The probability of all these things is 1 ... because they have actually been observed.

It might be a good idea, BeAChooser, to start at the beginning, with any one of these - but just one - and write out each step in the calculation (on a separate line), and leave the numbers out (use symbols, perhaps).

It might be a good idea, DRD, to go back and read post my #125 ... because I think you missed it. You certainly didn't respond to it ... just this later one where I assumed you'd read it.

Do that ... then ask yourself if you really wish you claim that the probabilties are 1 in this case to remain as your final word on the subject. Because I'm fine with that if that's what you want to do.

Let's ask Wrangler. Do you think that statement of DRD's shows an understanding of the calculation I made or an appreciation of the probabilities involved in this case? Do you think the probability of Arp finding a galaxy with precisely those 5 redshifts very near a galaxy is 1 ... or do you wish to stand by the statement you made that I'm right in saying "Arp encountering this out of pure coincidence is serendipitous, and the probability is very low"?

 

[BeAChooser]

But i don't recall you sampling all the galaxies or even a representative sample, you extrapolated from a small sample to the galaxies as a whole, did you not?

I see you still have trouble with reading comprehension. Or did you miss post #125 too? Well no, that can't be it since you responded to post #125.

What is the total set of QSOs and how are they arranged,

I said what I assumed. And I thought what I assumed was quite reasonable and complete. Tell you what, David, you tell us the total number of QSOs in the sky of the magnitudes of interest here. I thought 30 per square degree was being conservative but you go ahead and pick the number to use. And tell us how you want them arranged. In other words, how many total galaxies will have at least 5 within a degree of them. You pick the number. And also, how many total galaxies do you think Arp actually looked at and studied for the presence of quasars. Then I'll redo the calculation with your numbers. Fair enough?

 

[Dancing David]

I see you still have trouble with reading comprehension. Or did you miss post #125 too? Well no, that can't be it since you responded to post #125.



I said what I assumed. And I thought what I assumed was quite reasonable and complete.

Why? Have you even addressed the issue of sampling and extrapolating statistics? have you actualy tried to address the critique?

have you?

Tell you what, David, you tell us the total number of QSOs in the sky of the magnitudes of interest here. I thought 30 per square degree was being conservative but you go ahead and pick the number to use. And tell us how you want them arranged. In other words, how many total galaxies will have at least 5 within a degree of them. You pick the number. And also, how many total galaxies do you think Arp actually looked at and studied for the presence of quasars. Then I'll redo the calculation with your numbers. Fair enough?

I see that you are starting your usual rudeness, can't stop your self eh?

the issue is that you don't understand the application of statistics in this case. i will go and find more information on sample bias and why you are not using statistics to the best effect.

But I do ask you to stop your patronising attitude. The smily face does not cover nor excuse your rudeness.

I am not going to make accusations at this time of your not reading what other people write. i will try to get you some referenced material that you can choose to ignore.

You haven't addressed the samplibg issue at all. You want to ignore it fine, but you are not applying your statistics well or the way that most people trying to make a scientific case are in the habit of using them, what is considered to be good practice.

Why don't you go and read about sampling bias and show me a mainstream reference on statistics that would say your equations have significance?

 

[Dancing David]

Did you read my links BAC?

http://sestat.nsf.gov/docs/stderr10.html

 

[BeAChooser]

Quote:
Tell you what, David, you tell us the total number of QSOs in the sky of the magnitudes of interest here. I thought 30 per square degree was being conservative but you go ahead and pick the number to use. And tell us how you want them arranged. In other words, how many total galaxies will have at least 5 within a degree of them. You pick the number. And also, how many total galaxies do you think Arp actually looked at and studied for the presence of quasars. Then I'll redo the calculation with your numbers. Fair enough?

I see that you are starting your usual rudeness

Now David, how can my giving you the chance to define the numbers used in the calculation possibly be considered "rude"? You keep saying that I am biasing the results by not using all the data. Well now is your chance to define what all the data means. You want to double the number of quasars from 50,000 (in the SDSS survey) to 100,000 ... or triple it ... or quadruple it? Fine. You don't want to evenly distribute those quasars, 5 at a time, on galaxies to obtain the maximum number of galaxies that could have 5? Fine. Go ahead and tell me the true distribution. Would you like to spread them out amongst the total number of galaxies the Hubble can actually see ... 1 per until we run out? Fine. Whatever distribution you want to choose, I will accept. And I'll even let you estimate how many galaxies Arp et al have examined, looking for suspicious quasar alignments. 25,000 seemed like a reasonable high side estimate to me but if you think another number is more likely ... offer it up.

Then we can do that calculation again and see what probability we come up after satisfying all your concerns about not having accounted for all the data.

the issue is that you don't understand the application of statistics in this case.

Really David? How about we do another calculation. Let's apply Bayes Theorem to this problem and see how well I understand it?

Let's consider that only two hypotheses are possible (one is that all quasars are distributed randomly and the other is that they aren't). Now the apriori probabilities for hypotheses A and B, as denoted by a superscript 0 to indicate that they exist before any experiment, yield this equation: Pr⁰(A) + Pr⁰(B) = 1.

Now suppose we perform an experiment and obtain a series of empirical values x_i (those would be the observation of the quasar redshifts in the cases I noted). Note that the probability of this sequence, under the assumption that hypothesis A is correct, is P_A(x_i) where the notion is changed slightly to indicate that it is the probability of a whole sequence of values that we are concerned with here.

The next step is to obtain Pr¹(A) as the result of the experiment ... which we do using Bayes' theorem:

Pr¹(A) = (Pr⁰(A) * P_A(x_i)) / (Pr⁰(A) * P_A(x_i) + Pr⁰(B) * P_B(x_i))

and

Pr¹(B) = (Pr⁰(B) * P_B(x_i)) / (Pr⁰(A) * P_A(x_i) + Pr⁰(B) * P_B(x_i))

As a result of our experiment we can either increase our confidence in A at the expense of B or do just the opposite.

Shall we now plug in some number?

Suppose apriori we are really sure that your hypothesis is correct. Let's say Pr⁰(A) = 0.999, leaving just a little room for doubt. That means Pr⁰(B) = 0.001. Fair enough?

Next, we "measure" that sequence of 5 redshift values from NGC 3516 that are all aligned with the minor axis of the galaxy. And based on the calculation I did in post #125, the probability of that sequence of values and alignment occurring under the assumption that hypothesis A is correct (P_A(x_i)) is calculated to be no better than 0.0015 ... assuming all the quasars I assumed we can see in the sky are distributed 5 at a time to as many galaxies as possible. (Now mind you, the real probability is even smaller since we've ignored the fact that the quasars are actually spread amongst far more galaxies.) At the same time, we can say that P_B(x_i) = 0.9985.

Now let's compute Pr¹(A) and Pr¹(B).

Pr¹(A) = (0.999 * 0.0015) / (0.999 * 0.0015 + 0.001 * 0.9985) = 0.60

Pr¹(B) = 0.40

In other words, based on that single observation, the probability that your hypothesis is correct has dropped from 99.9% to 60% and the probability that the quasars' redshifts and positions aren't just a matter of random change has risen to 40%.

And that's after looking at only the first of the cases I noted.

(I apologize apriori for my smily face. I just liked the result.)

You haven't addressed the samplibg issue at all.

Actually, I think I have, David. And quite effectively, gauging from the response.

 

[Dancing David]

Uh huh, you are once again avoiding the issue, I am very tired and not going to engage in your mind games tomight. You are rude, questioning my reading comprehension.



You have not addressed the census population, you have not addressed the representative samples.

Please show where you referenced you population size and your sample size?



What is the confidence interval of your sample given the population size? What is the population size? What representative sample have you used? What is your sample size?

None that i can see.

As usual you are using fantasy as the realm of your equations. What are the representative samples you are using?

Where are your norms, standard deviations and the like. How did you randomise your samples for your sets?

You used two extremes of an imaginary set, as usual you seem to give precendence to an imaginary schema rather than reality.

So what repersentative sample are you using? One where quasars are randomly distributed and one where they aren't, could you point me to where you observational data came from? Which sky survey produced those sets?

 

[Dancing David]

In my muddled state I also forgot to point out that you just failed high school probablity.

You keep linking events to show that something has a lower chance of occuring, that just shows you haven't a clue about random distribution.

You flip a coin ten times and it comes up ten heads in a row, what is the proability that the eleventh toss will be a head?

It is 50% BAC, the prior occurance of a head has nothing to do with the prior tosses, yet you continue to make this error , over and over and over.

So not only do you not understand statistics, it would appear you don't understand probability either.

 

[BeAChooser]

You are rude, questioning my reading comprehension.

And I wonder why I did that?

Well just look at this from your latest post.

Please show where you referenced you population size and your sample size?

How did you randomise your samples for your sets?

 

[BeAChooser]

In my muddled state I also forgot to point out that you just failed high school probablity.

You keep linking events to show that something has a lower chance of occuring, that just shows you haven't a clue about random distribution.

You flip a coin ten times and it comes up ten heads in a row, what is the proability that the eleventh toss will be a head?

David, the coin toss samples are completely independent events drawn from a process with the exact same probability of producing a head every single time. Do you think that the likelihoods of quasar/cluster arrangements and redshifts are completely independent of one another? When you identify a sample in the population by naming it, don't you remove it from the population for drawing the next sample? Look at it this way, if you have a field of walnut shells with one pea under one of the shells there is a certain probability that you will find a pea if you lift a shell. If that shell contains the pea, do you think the probability of finding a pea if you lift another shell is the same? Apparently so.

So not only do you not understand statistics, it would appear you don't understand probability either.

Right David.

So David, are you ever going to get around to providing me with some numbers (for quasars, galaxies, distribution and the completeness of Arp's survey) so that I can run that calculation over to your liking?

 

[DeiRenDopa]

There seem to be two different ideas at play, the improbability of a certain configuration of objects ('quasars'), and a patern in observed (quasar) redshift distribution(s).

Taking the first one for this post.

Improbable things happen all the time - someone wins a lottery, for example, or some highly unlikely combination of circumstances leads to an unfortunate accident.

True. But that doesn't rule out the possibility that the two phenomena are connected ... especially if it turns out the high redshift x-ray emitting object near galaxies are improbably quantized and distributed in a pattern matching the theory that Arp, Narlikar, et al have proposed for their origin and behavior.

.
I'm still not at all clear on what you're trying to say here; would you mind clarifying please?

Specifically, I am not aware of any "theory that Arp, Narlikar, et al have proposed" which quantitatively accounts for "high redshift x-ray emitting object near galaxies [...] improbably quantized and distributed in a [specific] pattern".

Where is that theory published? Where are the specific, quantitative behaviours explicitly derived from that theory?
.

So what's the probability that you can find some really cool configuration ('alignment') of stars across/around a galaxy? If you go looking for such a configuration, without first stating what it is you are looking for, it's almost certain you will find one!

But in the case of the curious redshift quantization examples I've listed, the predicted redshift quantization values were defined before those specific cases were found and studied by Arp. So your objection doesn't appear to apply in this case. So let's deal with this case rather than just waving hands ... Fair enough?

.

No, not really, if I may say so.

The post of yours I was replying to was quite ambiguous - it seemed to refer to two different things, as I made clear in my intro. The rest of my post dealt with the first, leaving the second to a later post ... and you responded as I have quoted.

BeAChooser, in one way I should thank you; what you wrote is good resource material for my study on why threads like these are often so long. In this case, it seems pretty clear that you either did not read what I wrote, or did not express yourself very clearly in the first place, or consciously and deliberately set out to mis-represent what I wrote and try to provoke an inflamed response.

The last is, of course, just what a troll does, and I note that many JREF forum regulars have called you just that.

If that's so, then it's an obvious conclusion - one reason why threads like this are so long is that people keep feeding the trolls.

However, I had hoped there was something more interesting, to do with the nature of science and of astronomy and astrophysics.

 

[DeiRenDopa]

Oh ... did I misinterpret your reasons for dismissing Bell when you quoted the source he cited saying "This catalogue should not be used for any statistical analysis as it is not complete in any sense, except that it is, we hope, a complete survey of the literature." and then said "As I said, earlier in this thread, this Bell paper is garbage, and should never have been published in ApJ."? Looks to me like you had only one reason ... that the data Bell used was in a source that made that statement ... which you even highlighted to draw our attention to it.

.
I am quite at a loss ... what do you intend to say here?

 

[DeiRenDopa]

To other readers ... let's see what DRD has to say about that calculation I did with respect to the probability of NGC 3516, NGC 5985 and NGC 3628 just being chance occurrences. Let's see if he actually deals with the numbers and probabilities ... or just hand-waves it away like David tried to do.

.
later.
.

Specifically, if the authors of a catalogue explicitly state their catalogue should not be used for statistical analyses, and someone proceeds to do just that, what degree of credibility do you think should be given to that someone's paper?

Well let's take a closer look at VCVcat (a.k.a. Véron-Cetty, M.P. and Véron, P. 2006, A&A, 455, 773), which is what Bell used. That would be this: http://adsabs.harvard.edu/cgi-bin/bib_query?2006A&A...455..773V whose abstract states "This catalogue is aimed at presenting a compilation of all known AGN in a compact and convenient form and we hope that it will be useful to all workers in this field. ... snip ... The present version contains 85 221 quasars, 1122 BL Lac objects and 21 737 active galaxies (including 9628 Seyfert 1s), almost doubling the number listed in the 11th edition. We also give a list of all known lensed and double quasars." I don't know, DRD ... that looks pretty complete to me.

And if "workers in this field" aren't supposed to use what would appear to be one of the more complete databases, tell us what are they supposed to use? Note that this NASA site: 1. http://heasarc.gsfc.nasa.gov/W3Browse/all/veroncat.html fails to mention the disclaimer that you quoted. Don't tell me NASA is using the data without regard to the disclaimer. Oh my!

And are there others using this data base or an earlier version of the catalog? Yes. See these:

2. http://arxiv.org/pdf/astro-ph/0611820.pdf "Photometric Selection of QSO Candidates From GALEX Sources, David W. Atlee
and Andrew Gould, 2007"

3. http://www.journals.uchicago.edu/doi/abs/10.1086/379006 "On the Cross-Correlation between the Arrival Direction of Ultra–High-Energy Cosmic Rays, BL Lacertae Objects, and EGRET Detections: A New Way to Identify EGRET Sources?, Diego*F.*Torres, Stephen*Reucroft, Olaf*Reimer, Luis*A.*Anchordoqui, 2005"

4. http://aps.arxiv.org/pdf/astro-ph/0703280 "Quantum Vacuum and a Matter - Antimatter Cosmology, Frederick Rothwarf and Sisir Roy, 2006"

5. http://www.auger.org/technical_info/pdfs/icrc2007/0706.1715v1.pdf "Search for correlation of UHECRs and BL Lacs in Pierre Auger Observatory data, Diego Harari, 2007"

6. http://www3.interscience.wiley.com/cgi-bin/abstract/113489988/ABSTRACT?CRETRY=1&SRETRY=0 "Automated spectral and timing analysis of AGNs, F. Munz, V. Karas, M. Guainazzi, 2006"

7. http://www.saber.ula.ve/db/ssaber/Edocs/centros_investigacion/cat/publicaciones/papers/isamp.pdf "Dynamic multiple scattering, frequency shift and possible effects on quasars astronomy, Sisir Roy, Malabika Roy, Joydip Ghosh, Menas Kafatos, 2007"

8. http://209.85.173.104/search?q=cach...tatistical+analysis&hl=en&ct=clnk&cd=27&gl=us "A Bar Fuels a Super-Massive Black Hole?: Host Galaxies of Narrow-Line Seyfert 1 Galaxies, Kouji Ohta, Kentaro Aoki, Toshihiro Kawaguchi and Gaku Kiuchi, 2006"

9. https://ritdml.rit.edu/dspace/bitstream/1850/1788/1/SBaumArticle11-2004.pdf "The host galaxies of luminous quasars, David J. E. Floyd, Marek J. Kukula, James S. Dunlop, Ross J. McLure, Lance Miller, Will J. Percival, Stefi A. Baum and Christopher P. O’Dea, 2006"

And I could go on. It appears almost no one is heeding that warning, DRD. So are all of the above apriori "garbage" or do scientists tend to use whatever data they can get their hands on and ignore the lawyerly legalize sometimes added by bureaucrats even to what would appear to be one on of the most complete databases available at the time?

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Do you mind if I ask how much formal training you have in the use of statistics in astronomy, BeAChooser?

How much familiarity you have with astronomical catalogues and their uses?

There are some interesting issues in what you write, which I think many readers of this thread/post might be interested in, but how I address them rather heavily depends on what level of understanding I can rely upon.

For now, just some quick comments.

(I've added numbers to the material you cited)

1. Part of the formal training that astronomers receive (or should receive) includes what catalogues are and how they can (and cannot) be used. If you actually use data from a catalogue, not only must you cite it, but any reviewer of your preprint is expected to have familiarity with the catalogue, and should point out when you are using it for a purpose for which it is not suitable.

2. Seems to be a perfectly OK use of VCVcat; how did you read this to be otherwise?

3. and 5. I haven't read the papers themselves, but the use of VCVcat seems OK for the purposes stated; how did conclude it was not?

4. This is a v3 preprint; I expect a reviewer doing her job right would suggest tightening the language a bit; however, the use of VCVcat isn't as so crazily wrong as it was in Bell's paper

6. Link didn't work

7. If the abstract is a fair guide to what's in the paper, then it looks like garbage (i.e. misuse of VCVcat for a purpose it is explicitly unsuitable for)

8. Seems to be a perfectly OK use of VCVcat; how did you read this to be otherwise?

9. Seems to be a perfectly OK use of VCVcat; how did you read this to be otherwise?

At a more general level, and on the topic of my current study, I thank you for this post, it will provide good material for questions I would like to ask you later, to help me sharpen my provisional conclusions on why threads like this are sometimes so long.

 

[DeiRenDopa]

I'm curious, DRD. Is the only case you will accept one where Arp, et al, predict before the fact there will be a quasar in front of a galaxy with what appears to be a jet coming from the nuclear toward it. They have to make the prediction before even looking at the galaxy otherwise that data can be dismissed? Is that the logic you work by? (part of post omitted)

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Of course not.

I thought I'd been quite careful in briefly summarising some key points about how to do this kind of astronomical research in an earlier post; maybe I should go over them again, in more detail?

On the other hand, I again thank you for providing me good material for my study (see previous post)
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Of course, spiral arms are not optically thick, not even in the x-ray band, as W. Kell has shown in a series of papers, and as this Chandra PR attests (work based on discovery of a hole by Lockman et al.).

Care to show us ANY evidence of ANY object behind the galaxy being seen through that region of the galaxy? Or are you just waving your hands?

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Would you mind explaining why this is relevant?

I mean, no one - not even Arp, Burbidge, et al. - claims that this particular part of this particular galaxy is somehow magical, are they? Surely the relevant question to ask is how transparent spiral arms of galaxies are, in the x-ray and visual wavebands?

By the way, there's a typo; it should be 'Keel'.

 

[DeiRenDopa]

Wrangler, DeiRenDopa, and Dancing David ... let's look closer at the probabilities of the alignment in NGC 3516 occurring by sheer coincidence. Recall, this is the case where 5 quasars aligned along a minor axis have 5 z's that individually match the quantized z's that Karlsson predicted in the 1970's (http://adsabs.harvard.edu/abs/1977A&A....58..237K Karlsson, K.G., "On the existence of significant peaks in the quasar redshift distribution", Astron. Astrophys. 58:237–240, 1977). Note that I am assuming these particular quasars weren't used in Karlsson's study so it's a prediction.

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Which five quasars, BAC? The NGC 3516 paper discusses six.
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Let's simplify the problem and just say that there are 30 possible values (or small ranges) of z ... from 0 to 3.0 ... in increments of 0.1. Now what are the number of permutations of 5 (r) ordered values from 30 distinct values? It turns there are n!/(n-r)! possibilities. Which in this case is 17,100,720. That means the probability of picking those 5 specific z's in order from a range of 30 z's is 5.8 x 10^-8.

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Except that two (of six) quasars do not match the predicted z within 0.1, and the range you chose is both arbitrary and too large (the highest peak you can consider is 2.1 ... otherwise you have to consider that two other predicted peaks in the range [0,3] were not observed, for example).
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Now the surface area of a sphere has about 4 PI 57² = 41,250 square degree areas. If we assume there are 30 quasars (just to pick a number I hope is conservative) per square degree (over the range of magnitudes we seem to observe) then there are a possible 1,237,500 quasars. That means there could be at most 250,000 groups of 5 located next to 250,000 different galaxies.

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I have no idea how you got from 'there are a possible 1,237,500 quasars' to 'there could be at most 250,000 groups of 5 located next to 250,000 different galaxies'; would you mind explaining please?

As the rest of the post I'm quoting requires the two items I've questioned to be correct, it doesn't seem to make much sense to continue.

... except to say that the conclusions in the first part of Chu et al. paper are also knocked out by the L-C&G one.