Dear Nereid and Phobos (seat belt on) can we talk about redshifts?

[Nereid]

correction, meteor (not turbo-1)

I didn't cite Stephan's Quintet as an example of interaction between discordant-redshift galaxies. I think the high resolution imagery from HST put that one to bed years ago. There are, however, examples of apparently-interacting objects with very discordant redshifts, one of which I mentioned in one of the first posts in this thread.

It was meteor, in this post

Good to know that surface-brightness fluctuations are accepted as a valid measure of distance (independent of redshift).

 

[turbo]

Turbo, please elaborate. In what way is Arp's statistical analysis more 'correct' than NT's? NT made no assumptions about system dynamics, Arp did.

Arp's "assumption" about system dynamics is one that you or I would make intuitively. It is gravity and orbital motion. In a cluster of galaxies, the group's members will exhibit motions relative to each other. The members will move along geodesics in curved space-time - elliptical orbits that conserve angular momentum. This is a given. The geodesics along which these orbits lie are functions of the masses and positions of the members of the group.

Remember that the largest objects in the group will be less-perturbed than their smaller neighbors, but they too will exhibit some proper motion relative to their neighbors. To envision this, remember that the Earth is perturbed by the mass of the moon as it orbits, just as the sun is perturbed by the mass of the orbiting earth.

Now, let's take the M81 system - 13 galaxies in all, with M81 being by far the most massive. M81's companion galaxies cannot just float out in space with no angular motion relative to their more massive host - with no angular momentum, they would simply follow the path of least resistance (inward radial path) toward the gravitational center of the system and be swallowed up by their huge host.

In a more Newtonian view, we say that the objects in a gravitational system orbit around their common center of mass. In a system where one large massive galaxy dominates, the common center of mass is very near (or in) the large host, and its proper motions relative to the small companions are rather small, while the motions of the smaller objects relative to the host are much larger. Observationally, the small companions of M81 must have proper motion relative to M81. Some should be moving away from us, some toward us, and some may be moving more or less perpendicular to our line of sight. This should result in somewhat fewer than 1/2 of M81's companions being redshifted relative to the host. Arp used a simple 50:50 ratio, which while somewhat inaccurate, was generous to his critics since it should have biased the results against his theory a bit.

As I have mentioned several times in this thread, Newman-Terzian made a HUGE assumption that everybody seems to overlook. If you will read the N-T paper, you will find it on page 1, section 2 Combinatorial Considerations. The authors *assume* a fully random distribution of motion among cluster members with no dynamical pattern whatsoever. They excused this by saying in essence "the system is too complex for us to normalize" so they entirely threw out all the laws of Newtonian gravitational theory and Einstein's space-time field. By doing so, they treated M31 as if were no more massive or gravitationally influential than the Large and Small Magellanic Clouds. That is patently absurd. Newman&Terzian smugly refer in their paper to "the error in Arp's combinatory approach" - there is high irony there.

Notice that they only discussed the M31 cluster, so they could claim that the closer relative masses of M31, MW and M33 hopelessly confuse the dynamic of the cluster. The situation with the M81 system is far more straightforward, though, with a very massive central galaxy. If we look out at the M81 cluster, we should expect to find the smaller companions to have measurable proper motion relative the host galaxy. Again some should be blueshifted, some should be redshifted, and some could be neutral due to orbital inclination or present-day orbital position.

Now do you see where N-T is flawed? They make the very radical assumption that the companions of a massive host galaxy do not need to have proper motion relative to the large galaxy, and that they can treat the largest galaxy as if it had no more gravitational influence than the smallest companion. This is wrong, and Einstein and Newton both would tell them so in an instant. The universe is in constant motion, and astronomical bodies follow geodesics in space-time (or orbits if you prefer) that are determined by the mass, speed, and location of the bodies. The largest body or bodies in their neighborhood contribute the bulk of the space-time distortion (or gravitational pull, if you prefer Newton). For those companion galaxies to exist at all, they MUST be exhibiting some angular proper motion relative to the host galaxy - otherwise, they would have fallen into the host long ago.

By assuming that the members of the M81 group do not need to exhibit any classical orbital motion relative to one another (a very radical assumption, again), N-T were then able to treat the redshift excess of the companions as a problem of ordination, saying there is a one in twelve (8%) chance that the largest object will be the least redshifted. Their paper completely ignored gravitational interaction and causation. It was the only way that they could use non-substitutive ordination to arrive at their very low probability that all the companions would be redshifted relative to their hosts. Their math is very basic, accurate, and easy to follow but the statistical methods they applied are entirely inappropriate to the data.

Arp offered no proof of this basic assumption. It is therefore suspect, at best, and mostly contraindicated by observational evidence. I am not a dogmatic fool, but, I am a sucker for observational facts and supporting math. So, from my reference frame, the Arp assumption is invalid.

Again, Arp's basic assumption was that galaxy clusters have to obey the classical laws of physics with regard to gravitation, motion, etc. This is not something that normally has to be stated in the introduction of any astronomy paper, so its absence should not be troubling. Newtonian gravitation and Einstein's space-time field theories are pretty well-established, so you'll have to have a pretty good reason to arbitrarily declare them invalid. The observational evidence DOES show that the companion galaxies are redshifted relative to their hosts. Arp did not make those observations - that was done a very long time ago. The observational evidence alone cannot/should not invalidate Newton/Einstein either, but there is something that does need to be re-examined - our understanding of the causes of redshift. Arp simply made the observation that if we expect the members of galactic cluster to behave in accordance with what we know about gravitation, some companions should be moving toward us and some should be moving away. The fact that all of M81s comapanions are redshifted relative to it means that either they are all somehow preferentially running away from us for some reason, OR there is something about redshift that we do not understand. It is a very simple concept. If smaller galaxies in clusters are preferentially redshifted relative to the largest members, either the Earth is at the most special place in the universe (forbidden by all credible cosmologies) OR there is something other than currently accepted causes (cosmological expansion, doppler shift, and Einstein's gravitational field effect) that must be responsible for the excess redshift.

Here's the math: if there is a 50:50 probablility of finding an object in a particular state, and you sample 11 such objects, the math is multiplicative. 1/2 x 1/2 x1/2... etc. With eleven objects with equiprobable states, that comes out to 1/(2 to the eleventh power) or 1/2048. Quite a far cry from 1/12. I used the number 11 as the number of objects because that is how many objects were included in the "analysis" that N-T gave the M31 group. There are actually 12 companion galaxies in the M81 group giving only one chance in 4096 that all of them will be redshifted relative to the host. They all are, and they all have significant recessional velocities.

Here is a link to a page on the M81 group with recessional velocities listed.

http://www.seds.org/messier/more/m081gr.html

I know I sound like a broken record talking about this N-T paper, and I wish that I could explain the basic logical flaws in it more clearly, because I seem to be missing the audience. I'll glady follow up (at the risk of boring everyone to tears!) if there are questions.

 

[Nereid]

Hi Nereid!

As you know, when I posted my critique of the Newman-Terzian paper, I did not dispute the observations quoted by either side. I kept my post focused on the statistical methods employed by both sides. The problem with the Newman-Terzian paper is that the authors stripped the gravitational influence of the largest body out of the analysis (which was a central point in Arp's presentation) and then presented the 12-body problem as a simple case of ordination. This is the best way to understate the odds that all eleven small companions would be reshifted relative to the largest body. The astronomical community gave this paper free pass, although any sharp 7th grader would have trouble letting it by.

In essence, the authors presented Arp's system of 12 bodies as a simple set of equivalent items, ignoring the gravitational influence of the (FAR more) massive body then said "there is a 1/12 chance that the largest body will be the least redshifted". This is VERY wrong. It is like a pair of cops barging into a room looking for a bank robber and finding eleven pre-schoolers and one adult with stain from a dye-bomb on him and concluding "there is a one in twelve chance that this is the person who robbed the bank".

As you point out, the authors state that "the dynamical picture presented by the group's members is highly complex - indeed, the potential for chaotic behavior in this dynamical system cannot be excluded". That statement does not excuse them from ignoring basic probability, however. In a chaotic environment, should we expect to find ALL the smaller bodies to be redshifted with respect to the largest body "some of the time", "most of the time", or "all of the time"? Chaotic behavior in complex systems permits short-term anomolies (even very unlikely ones) but it does not trump probability in the long term or over multiple samples.

To summarize again, N-T did not dispute Arp's redshift characterizations of either of the galaxy groups (2 groups, each with eleven companions around more massive galaxies) nor did I. They challenged Arp's statistical methodology, and they presented alternative "analyses" that were very badly flawed, even cynical. Arp-bashing is popular and easy, but I think you would have trouble getting the authors to defend that paper today.

Can you give us a link to an online copy of the 1994 Arp paper? Without reading what N&T were responding to, it would be better for me to say little more (re content).

 

[Chronos]

Here is link to Arp paper referenced in NT paper

http://adsabs.harvard.edu/cgi-bin/n...J...430...74A&db_key=AST&high=3cf96e067121063

 

[turbo]

Can you give us a link to an online copy of the 1994 Arp paper? Without reading what N&T were responding to, it would be better for me to say little more (re content).

Sure! I found it pretty easily and I had foolishly assumed that everyone interested in this thread had reviewed it. The "fingers of God" distribution of galaxies in the Virgo cluster, the K-effect (intrinsic redshifts of supermassive young stars in our own galaxy, SMC, and LMC), and other arguments for intrinsic redshift are presented in the paper, but the real giant-killer is the very simple straightforward examination of already-existing redshift measurements in the M31 cluster and the M81 cluster.

http://adsabs.harvard.edu/cgi-bin/n.....74A&db_key=AST&high=40f19ad6db11758

 

[turbo]

Thank you Chronos, a most interesting read.

This paper should allow us to put several 'association' and 'quantized z' hypotheses to sleep. Does anyone know if any serious astronomers in either of those camps are still banging those drums?

Now that some SDSS results are in the public domain, perhaps a similar piece of research could be done using those? The good news is that SDSS uses a completely different method to select objects for specta than 2dF did, so if similar analyses of the two datasets yield similar results there'll surely be no place to hide!

I particularly liked the approach taken here: a proponent in one camp suggests a method of analysis, and a neutral third party carried out the work, using publicly available data. What's good? The method and expected outcomes were clearly defined BEFORE the work was done, and the datasets are in the public domain (you don't like the conclusions? there's nothing at all stopping you from performing your own analyses!)

Yes, thank you for the link Chronos! Nereid summed up my feelings pretty well. As we discussed earlier (in this thread, I think) I feel that there is solid observational evidence for intrinsic excess redshift, but I am philosophically (intuitively, more likely) repelled by the thought that redshift might be quantized. I am prepared to accept a mechanism for excess redshift that can produce a smooth continuum of values, but quantization of redshift values in objects as apparently violent and energetic as quasars just goes against my grain. Please note the very precise reasoning (including all relevant maths) for my position.

 

[Nacho]

Arp and his ideas have been one of my favorite readings, but I've kinda lost contact since some of the observations of the last few years.

Good to see he's still out there "giving 'em hell"!

 

[Nereid]

Sure! I found it pretty easily and I had foolishly assumed that everyone interested in this thread had reviewed it. The "fingers of God" distribution of galaxies in the Virgo cluster, the K-effect (intrinsic redshifts of supermassive young stars in our own galaxy, SMC, and LMC), and other arguments for intrinsic redshift are presented in the paper, but the real giant-killer is the very simple straightforward examination of already-existing redshift measurements in the M31 cluster and the M81 cluster.

http://adsabs.harvard.edu/cgi-bin/n...J...430...74A&db_key=AST&high=40f19ad6db11758

Been meaning to post a reply to this for quite a while now. Thanks Chronos and turbo-1 for the links.

The Arp paper was richer than turbo-1's build up implied (to me anyway). For example, it contained a section ("Comments on Galactocentric Corrections to Heliocentric Spectral Shifts") that introduces an important consideration which makes the LG a much more difficult group to study (in terms of Arp's thesis). In fact, given how massive the Milky Way is (wrt M31), and the lack of any data (?) on transverse motions, I wonder how any conclusion about the LG could have been drawn from the data Arp had available at the time.
Arp 0, N+T 0.

So if just the M31 sub-cluster (my term, not Arp's) is examined, then there are surely too few data points in Arp's paper to make any kind of case.
turbo-1 0.

What about the M81 group? N+T's paper didn't examine this, and Arp's didn't give a table of values, just a figure (with 11 group members, other than M81). In this case, the galactocentric corrections are much less problematic, and the measured radial velocities apparently accurate enough. Interesting case.
Arp 1.

Then we have the fingers of god. I didn't read this part too carefully, partly because it's obvious that there's far, far more high quality data now than when Arp wrote in 1994.

Which brings me to an important point. Arp’s paper is now 10 years old, and reading it one has a faint sense of surprise … only 25 LG members (cf 45+ recognised today); some tough calls about LG membership (cf the ease with which stars can be resolved in target galaxies today); no mention of high velocity clouds, star streams, etc; how the determination of redshifts then were apparently a rather big undertaking (cf 2dF and SDSS, which routinely took/take hundreds in one go); …

Surely a month or two’s work, mining some of the existing, public astronomical databases could increase the amount of data relevant to Arp’s thesis by an OOM or two?

 

[turbo]

So if just the M31 sub-cluster (my term, not Arp's) is examined, then there are surely too few data points in Arp's paper to make any kind of case.
turbo-1 0.

Didn't you mean turbo-1 1? I pointed out that the closer relative masses of MW and M31, etc made the local group problematic - which is WHY N-T chose it to try to refute Arp. If they had chosen the M81 group, they could not have made any logical argument against Arp's thesis, or at least they wouldn't have been able to slip their "non-substitutive ordination" trick past the referees (I hope :yuck:). I explained why N-T decided to use the local group at least a couple of times in the thread. Perhaps I wasn't clear.

What about the M81 group? N+T's paper didn't examine this, and Arp's didn't give a table of values, just a figure (with 11 group members, other than M81). In this case, the galactocentric corrections are much less problematic, and the measured radial velocities apparently accurate enough. Interesting case.
Arp 1.

Yes, very interesting indeed. If all of M81's neighboring galaxies have decided to run away from Earth, we must be a scary bunch! Seriously, no reputable cosmological model permits us to occupy such a priviliged location in the Universe, not only with respect to the apparent preferential recession of M81's companions, but also with respect to the much larger "Fingers of God" artifacts that show up in our redshift data. To those not familiar with this, just Google "Fingers of God" and you will find otherwise rational people discussing the artifacts, with some really clever explanations as to how they can be explained away. (You'll laugh! You'll cry! ) More "epicycles" to tack onto our cosmology to hold it together... The artifacts in the data are real, but they are not due to "streaming effects" etc, etc (which put us back in the forbidden favored-observer position), but are instead due to a deficiency in our understanding of the causes of redshift. The Cosmus site
http://astro.uchicago.edu/cosmus/projects/fog/
calls these artifacts "glitches" and has done us all a favor by removing them from their fly-through visualization of the SDSS data. How nice of them. There is something causing these apparent redshift differentials that we do not fully understand. Since understanding and accurately measuring redshift is a vital tool in cosmology, you'd think that we would pour funding into discovering the deficiency in our understanding of redshift that allows the "Fingers of God" to show up in our redshift maps. Instead, those scholars simply "retouched the images" to make those disturbing artifacts go away. So sad. That is not science, it is the negation of science in the protection of orthodox beliefs. Edwin Hubble is probably spinning in his grave. Redshift=distance has been a very handy approximation, but it is only a tool, not an immutable law of the Universe. It's time to refine the model.

We KNOW that the artifacts exist in our redshift maps (SDSS data) and we KNOW that the F.O.G. cannot be due to the actual distributions of the galaxies. Logically then, our measurements of redshift cannot be strictly interpreted to equate to distance. Case closed. What other causative factor(s) can there be for the redshift differentials? That is one of the biggest questions still hanging...and cosmology is due for a thrilling ride when enough people start asking the right questions.

When the sacred redshift=distance has to be modified (and it WILL), it will put a lot of balls in play, including the Big Bang, cosmological expansion, the nature of quasars, "missing mass", etc, etc. Now would be a great time to be starting out as a student of Physics/Astronomy/Cosmology because the field will be wide-open for bright open-minded researchers.

 

[Nereid]

Quite a response turbo-1! Just to get back quickly on a couple of things:

- M81 group: if 20 members of the LG have been added in ~10 years (nearly doubling its membership), how many 'unseen' members of the M81 group are there? How much has our understanding of this group advanced in a decade? Some examples: is it really an isolated group (maybe there is an attractor)? what is the distribution of dwarf galaxies (perhaps these really do matter in the group, being the tip of very large DM icebergs)?

- fingers of god: I don't think that you did justice to the consensus view of these. In a few words, if cluster members are gravitationally bound, they will have to/from Earth motions (observed as redshifts) reflecting their 'orbits' in the cluster. If the cluster is relaxed, we can measure those motions, apply the virial theorem, and get an estimate of the total mass of the cluster. The more massive the cluster, the greater the dispersion of redshifts around the cluster (weighted) mean. These dispersions will show up, on 2dF or SDSS sky maps, as fingers of god. None of this is a big secret; in fact, these cluster dispersion measures of cluster mass are one of the sets of observations which imply lots of dark matter in clusters (and one which is, IIRC, inconsistent with MOND).

Arp asserted that there is a considerable excess of 'from' motion (higher redshift than the cluster mean) than 'to' motion (lower redshift), at least for the Virgo cluster. I said that Arp's assertion should be able to be tested using the huge amount of data that we now have.

In the next post, I will propose a research project, for you and me and at least one other person (of course, all PF members are welcome to join), to do a simple test of Arp's fingers of god assertion.

 

[turbo]

- M81 group: if 20 members of the LG have been added in ~10 years (nearly doubling its membership), how many 'unseen' members of the M81 group are there? How much has our understanding of this group advanced in a decade? Some examples: is it really an isolated group (maybe there is an attractor)? what is the distribution of dwarf galaxies (perhaps these really do matter in the group, being the tip of very large DM icebergs)?

What kind of attractor could pull M81's companions from its grasp? There is no visible object in that direction that serves the purpose, and the gravitational force of the attractor would have to be huge. I think we can discount that one, unless it is a huge well of "dark matter" located very near the opposite side of M81 from us. (another preferred-observer situation)

- fingers of god: I don't think that you did justice to the consensus view of these. In a few words, if cluster members are gravitationally bound, they will have to/from Earth motions (observed as redshifts) reflecting their 'orbits' in the cluster. If the cluster is relaxed, we can measure those motions, apply the virial theorem, and get an estimate of the total mass of the cluster. The more massive the cluster, the greater the dispersion of redshifts around the cluster (weighted) mean. These dispersions will show up, on 2dF or SDSS sky maps, as fingers of god. None of this is a big secret; in fact, these cluster dispersion measures of cluster mass are one of the sets of observations which imply lots of dark matter in clusters (and one which is, IIRC, inconsistent with MOND).

There is no big secret, here, but there the "consensus view" is full of misdirection and apologia regarding these artifacts. There is no doubt that the Fingers of God distribution of galaxies in the SDSS data exists. There is considerable differentiation, however, in the explanations regarding how the artifacts arose, and the "proper" methods by which they should be filtered out. I will not attempt to explain away or refute every "epicycle" that has been floated to try to massage these artifacts away. The F.O.G. are in the data and have not been adequately explained.

I suggest that the SDSS data is accurate. Nothing more. Given that the data is accurate, and given that the Earth cannot be at the center of the Universe (in the sense of a preferred reference point) we must come to the understanding that our redshift data does not accurately describe the distribution of the galaxies observed. That is a given. You say that orbital motions of galactic clusters will distort their redshifts to stretch the apparent shape of each cluster so that it appears pointed toward us. Do you see a parallel with the "shape" of the M81 group (M81 "closest to us", companions "streaming away")? This should be a cause for reflection.

Arp asserted that there is a considerable excess of 'from' motion (higher redshift than the cluster mean) than 'to' motion (lower redshift), at least for the Virgo cluster. I said that Arp's assertion should be able to be tested using the huge amount of data that we now have.

In the next post, I will propose a research project, for you and me and at least one other person (of course, all PF members are welcome to join), to do a simple test of Arp's fingers of god assertion.

I have been working about 60 hours a week on a very large project that is critical to my company, and I see little respite for the near term (another 3 months or so), so I hope the proposed project is not time-intensive. I have had a few moments today to post, but worked most of the day, and expect to have to work all Sunday, as well. Bleah! :yuck: I welcome the prospect that others may join in the investigation into the source of the F.O.G. I must say up-front, however, that some *very* competent folks have been working for years to make those Earth-centered radial streaks in the SDSS data "go away", with varied degrees of success.

The artifacts are in the data, and rather than invent mechanisms to refute them, we would be better served by an open-minded effort to discover what deficiency in our understanding of redshift allows these distortions to exist.

 

[turbo]

- fingers of god: I don't think that you did justice to the consensus view of these. In a few words, if cluster members are gravitationally bound, they will have to/from Earth motions (observed as redshifts) reflecting their 'orbits' in the cluster. If the cluster is relaxed, we can measure those motions, apply the virial theorem, and get an estimate of the total mass of the cluster. The more massive the cluster, the greater the dispersion of redshifts around the cluster (weighted) mean. These dispersions will show up, on 2dF or SDSS sky maps, as fingers of god. None of this is a big secret; in fact, these cluster dispersion measures of cluster mass are one of the sets of observations which imply lots of dark matter in clusters (and one which is, IIRC, inconsistent with MOND).

OK, a couple of difficulties with the consensus view of the FoG. For the reshifts of these galaxies to be smeared radially as they are in the data, their orbital velocities need to be very large - somewhere on the order of 1000 km/s. To produce those velocities, the central galaxies would have to be VERY massive (here comes the elusive dark matter again).

Another problem: as you pointed out, we would expect the smaller glaxies to swarm around the largest galaxy in each cluster, some moving toward us and some away from us to produce the radial smearing. Why don't we see that orbital motion expressed in the M81 cluster? As you can see in the Tully catalog quoted here (the basis for Arp's calculations):
http://www.seds.org/messier/more/m081gr.html
M81's companions are all preferentally streaming away from us. The shape of the cluster would seem to be elongated (with M81 closest to us and pointing at us), but this effect is not caused by orbital motions of the small galaxies. The orbital motions of these small galaxies must contribute to their measured redshifts, but that contribution is overwhelmed by *something* that gives them much more excess redshift and makes them appear to be all receding from us relative to M81.

Another little wrinkle: on larger scales, the Kaiser Effect would dominate, causing the clusters to look flattened, not elongated. It is suggested by conventional cosmologists that this effect only occurs on supercluster scales, but it's evident that there is a lot of "wiggle-room" in the consensus view.

 

[rob_we]

I have two questions to anyone who knows..

First: Are there known interacting systems with more or less equal mass with a redshiftdifference like this (M51)

Second: Are there known interacting systems like M51 consisting of a bigger and a smaller system with no redshift difference?

thanks in advanve

Rob :)

 

[turbo]

Are there known interacting systems like M51 consisting of a bigger and a smaller system with no redshift difference?
Rob :)

If I can be permitted to modify your question just a bit, "are there known interacting systems like M51 in which the smaller companion has LESS redshift than the dominant galaxy?" This should happen about 50% of the time, if redshifts are caused only by cosmological distance (due to expansion) and by the proper motion of the associated galaxies.

ADDED: Actually, the smaller companion should have more redshift less than 50% of the time. There will be times when the proper motion of the small galaxy is perpendicular to our line of sight, and therefore should exhibit no redshift differential. The instances when the redshift of the smaller galaxy is less than or equal to the host should therefore outnumber the instances when the smaller galaxy has the greater redshift. END OF ADDITION

If the small companions are more redshifted than their hosts a statistically significant percentage of the time, then there must be something we don't yet understand that is producing the excess redshift.

 

[Nereid]

Welcome to Physics Forums rob_we!

Your last post was quite interesting, but did you know that we have an entire section devoted to the exploration of theories such as yours? It's called Theory Development.

Perhaps Phobos or Janus could move rob_we's post there, as the start of a new thread (with a link back to this thread)?

 

[selfAdjoint]

rob_we's post has been moved to Theory Development.

 

[turbo]

Now that some SDSS results are in the public domain, perhaps a similar piece of research could be done using those? The good news is that SDSS uses a completely different method to select objects for specta than 2dF did, so if similar analyses of the two datasets yield similar results there'll surely be no place to hide!

Hi Nereid! I thought you might want to see this. I have been quite uncomfortable with the concept of "quantization" of quasar reshifts, but the quasars pulled out of the SDSS data do seem to cluster. Any comments?

http://citebase.eprints.org/cgi-bin/citations?id=oai%3AarXiv%2Eorg%3Aastro%2Dph%2F0409025

 

[Chronos]

Hi Nereid! I thought you might want to see this. I have been quite uncomfortable with the concept of "quantization" of quasar reshifts, but the quasars pulled out of the SDSS data do seem to cluster. Any comments?

http://citebase.eprints.org/cgi-bin/citations?id=oai%3AarXiv%2Eorg%3Aastro%2Dph%2F0409025

I would be reluctant to cite that paper as authoritative. He makes a number of assertions that are, at best poorly explained; e.g.;

1] "If high-redshift quasars are ejected from the nuclei of low-redshift galaxies, as some have claimed, a large potion of their redshift must be intrinsic [non-Doppler]."
a) What about high-redshift quasars that cannot be associated with low-redshift galaxies [which are intrinically much brighter than their ejected offspring, according to this paper]
b) Non-Doppler? It has generally been assumed that redshifts exceeding z=1 are exclusively non-Doppler. What mechanism explains Z>2 intrinsic redshifts? Gravity?

2]"Since the term local model can be misleading, by implying that all quasars are local, the term decreasing intrinsic redshift model (DIR model) will hereafter will be used"
a) While the term 'DIR model' is indeed used thereafter, a description of the 'model' is conspicuosly absent, aside from claiming it mostly makes the same predictions as the standard model.

Upon checking, I concluded Bell has a history of writing almost exclusively in support of intrinsic/quantized red shift and QSO ejection models, and makes generous use of speculative assumptions.

 

[turbo]

I would be reluctant to cite that paper as authoritative. He makes a number of assertions that are, at best poorly explained; e.g.;

Ignore his assertions for now. Just look at Figure 1 for a while. The clustering of the SDSS quasar redshifts should raise questions. Is there any mechanism you can think of that would cause the clustering at these redshift values? In past studies, such clustering has been attributed to faulty selection criteria, sensitivity/binning artifacts, etc.

1] "If high-redshift quasars are ejected from the nuclei of low-redshift galaxies, as some have claimed, a large potion of their redshift must be intrinsic [non-Doppler]."
a) What about high-redshift quasars that cannot be associated with low-redshift galaxies [which are intrinically much brighter than their ejected offspring, according to this paper]
b) Non-Doppler? It has generally been assumed that redshifts exceeding z=1 are exclusively non-Doppler. What mechanism explains Z>2 intrinsic redshifts? Gravity?

He made the point quite clearly that "Hubble flow" and "Doppler" effects, caused by cosmological expansion and proper motion, respectively, cannot explain the clumping of the quasar's redshifts around certain values. Not everybody assumes that redshifts exceeding z=1 are "exclusively non-Doppler".

2]"Since the term local model can be misleading, by implying that all quasars are local, the term decreasing intrinsic redshift model (DIR model) will hereafter will be used"
a) While the term 'DIR model' is indeed used thereafter, a description of the 'model' is conspicuosly absent, aside from claiming it mostly makes the same predictions as the standard model.

He is citing an evolutionary model for quasar production proposed by Arp, Burbidge, et al. Quasars are ejection phenomena. They start out at high redshift and evolve to lower-redshifts. This is a model of quasar evolution only, not an over-arching cosmological model.

Upon checking, I concluded Bell has a history of writing almost exclusively in support of intrinsic/quantized red shift and QSO ejection models, and makes generous use of speculative assumptions.

You will find that Arp and Burbidge (and others) write about intrinsic redshifts and quasar ejection. That does not make them wrong. Their model makes a lot more sense than the standard model, which places quasars very far away based on their redshifts.

Believers in the standard model think the redshift of quasars is due to cosmological expansion, which places them at huge distances. This causes quasars to have properties that are a lot more troubling than intrinsic redshift, including:
1) More energy output than a hundred galaxies
2) Very highly organized and powerful even in the infancy of the universe (a problem for the heirarchical model)
3) Short-term output fluctuations that limit their size (smaller than the diameter of our solar system)
4) Some ejection jets that exhibit apparent superluminal motion
All of these problems go away if quasars are relatively nearby objects with intrinsic redshift. Is the Hubble redshift/distance relationship so sacred that we must accept monsters with these problems to prevent its violation?

Questions: If a black hole is slingshotted out of the center of a galaxy and starts gobbling matter, what would it look like? Would it look very energetic? If its accretion disk was initially very small and close to its event horizon, would the light from that disk be very redshifted? Would the redshift of the light from that disk gradually decrease as the disk gets larger and extends farther from the intense gravity well of the black hole? These questions lead to a very over-simplified model of quasar evolution that is nevertheless a lot more palatable than the standard model (see problems 1-4 above).

I am still not comfortable with quantization or preferred redshift values, but Figure 1 is pretty compelling. If the redshifts of quasars are entirely due to cosmological expansion, we should see a smooth distribution of quasar redshifts, but here is the SDSS sample of over 5000 quasars, and their redshifts are clumped in a regular fashion. Is there any way to explain this clumping without invoking intrinsic redshifts? If so, I would like to hear about it.