Quasar Anomalies: Lack of Time Dilation in Variability

[ratfink]

Before embarking on this project, it might be best to consider if a ‘quasar evolution model’ stands a chance of being consistent with observational data.

If we assume that the Hawkins paper is correct in its results and that there is no time dilation (within the 2 sigma confidence limits) then we must ask ourselves what this means and talk quantitatively about the consequences.

On the scales of these redshifts, time dilation should be exhibited – but it is not. So, if the ‘non time dilation’ is due to evolution then the evolution process must ‘squash’ the light curves in a reverse manner to expansion, which stretches them – and at the same rate.

That is, younger and more distant quasars must ‘wink’ at a much faster rate than older and nearer quasars so that when effects of time dilation are taken into account, they both ‘wink’ at the same rate here on Earth. Ignoring acceleration of the universe, this evolution model must be linear with distance and hence time, and also imply that all the quasars were formed at the same time – otherwise one would have to include ‘point of creation dependency’ in ones equations. OK so far?
Personally, I feel that this is pushing the limits of credulity too far.
If one must look for an explanation of the light curves that is internally consistent with the expansion model, then might it be better to talk about quasars having a consistent light curve but are lensed by a nearby galaxy? Then one could hand wave about the nearby galaxy producing the variation in light curves and, since it is close, there would be no time dilation effects.

Though personally, I prefer the non expansion explanation.

 

[Garth]

First - there have been other papers by Hawkins on the same no-time-dilation effect in quasar variability such as Nature 366, 242 - 245 (18 November 1993); (definitely not a journal for crackpots!) http://www.nature.com/nature/journal/v366/n6452/abs/366242a0.html;jsessionid=B68F2073D4B04C195A14FDABD18C7A55.

Second - Hawkins has published other papers on his favourite explanation for the phenomenom - http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1996MNRAS.278..787H&data_type=PDF_HIGH&type=PRINTER&filetype=.pdf[/URL] he argued that this effect, along with a number of other properties of the light curves, are best explained by gravitational microlensing of the quasar continuum region. A population of Jupiter sized primordial BHs with a total density contribution of $\Omega_{BHs} = 0.1$, (i.e. not baryonic matter) is responsible.

Not such an outlandish suggestion after all!

[quote=ratfink]Though personally, I prefer the non expansion explanation.[/quote] In which case you have to explain why distant SN and (apparently) long GRBs [b]do[/b] exhibit time dilation.

Garth

 

[Nereid]

Thanks Garth - the Dark matter from quasar microlensing is the 1996 Hawkins paper* I referred to earlier; it contains more details on the observing program, the data reduction techniques, some (different) analyses of (observed) variability, some wider thoughts on possible causes of the (apparent) lack of time dilation, and so on.

Towards the end of the paper we read the following:

None of these arguments [concerning physical processes which might, or could not, generate the observed characteristics of variability in quasars] precludes the possibility of a theory of intrinsic variation, which is consistent with the observations, although current AGN models [...] do not seem to produce variation of the observed character.

[*Edit: seeing the comments about Nature, I decided to edit this post to add that this 1996 paper was published in MNRAS!]

 

[SpaceTiger]

Nature 366, 242 - 245 (18 November 1993); (definitely not a journal for crackpots!)

The journal has developed into a sort of a running joke around here. People often publish in Nature if they have a really exciting result. Unfortunately, the most exciting results are also the most outlandish and are usually wrong, so a large fraction of Nature papers end up being totally bogus.

It's not a crackpot journal, to be sure, but those papers are viewed with a lot of skepticism in the community.

 

[Garth]

I think they tend to go on the reputation of both the institution and author from whom the paper is submitted.

Garth

 

[Nereid]

Before embarking on this project, it might be best to consider if a ‘quasar evolution model’ stands a chance of being consistent with observational data.

OK

If we assume that the Hawkins paper is correct in its results and that there is no time dilation (within the 2 sigma confidence limits) then we must ask ourselves what this means and talk quantitatively about the consequences.

That's what the project sets out to do (besides having fun).

On the scales of these redshifts, time dilation should be exhibited – but it is not. So, if the ‘non time dilation’ is due to evolution then the evolution process must ‘squash’ the light curves in a reverse manner to expansion, which stretches them – and at the same rate.

No. It only needs to 'squash' them to the extent that produces results which are consistent with the observational data. The difference between 'the same rate' and what I just wrote may seem small, almost trivial, but it is a trap that thinking about things like this in a qualititative way ("the same rate") can too easily lead you to fall into.

That is, younger and more distant quasars must ‘wink’ at a much faster rate than older and nearer quasars so that when effects of time dilation are taken into account, they both ‘wink’ at the same rate here on Earth.

And this oversimplification is another trap - if the light which we observe, here on Earth, from a quasar comes from several different regions (accretion disk, jet, etc), each of which is driven by different -though somewhat coupled - physical processes, then a priori I would say it's impossible to estimate anything about the integrated 'winking', using the kind of reasoning you're using here.

Compare this with 1a SNe - a single 'region', and one set of physical processes, suffice to produce all the light we see (until well past the peak).

Ignoring acceleration of the universe, this evolution model must be linear with distance and hence time, and also imply that all the quasars were formed at the same time – otherwise one would have to include ‘point of creation dependency’ in ones equations. OK so far?

As we've seen, none of this sentence applies - the logic broke down before it even got started.

Personally, I feel that this is pushing the limits of credulity too far.

And personally, I feel that skipping over important details early in the chain of reasoning all too often leads to incredulous results (or, if you prefer, conclusions that should be re-thought).

If one must look for an explanation of the light curves that is internally consistent with the expansion model, then might it be better to talk about quasars having a consistent light curve but are lensed by a nearby galaxy? Then one could hand wave about the nearby galaxy producing the variation in light curves and, since it is close, there would be no time dilation effects.

Interesting idea ... and that (and variations) is what Hawkins in fact did, in a series of papers.

 

[selfAdjoint]

Nereid, would this post by Space Tiger on the Eddington luminosity of the accretion disc be relevant to your project?

https://www.physicsforums.com/showpost.php?p=937955&postcount=42

 

[ratfink]

So, Nereird.
what constraints do you feel that a quasar evolutionary theory might have on the Hubble law?

 

[turbo]

First and foremost, in the mainstream view of quasars, we have quasar evolution - http://arxiv.org/abs/astro-ph/0005368" , perhaps. If high-z quasars are different from low-z ones, then, a priori, expecting their (rest frame) variability to be unchanged is rather foolish, isn't it?

I have linked this lecture video on another forum, but feel that it is relevant here, and I do not know if you have watched it or not. The presenter is Michael Strauss of the SDSS team and he demonstrates that high-redshift quasars are just like low-redshift quasars in all measurable respects. Interestingly, there is no evolution in either absolute or relative MgII and FEII abundances all the way out to z~6.5, although those metals are believed to be generated by different supernovae classes.

http://www.stsci.edu/institute/center/information/streaming/archive/STScIScienceColloquiaFall2005/MichaelStrauss110205

 

[pallidin]

Sorry to jump into this thread with my having little authorative knowledge, but I have a few questions I would like to ask in order for me to more properly understand the "jist" of the comments:

1) Are Quasars currently the most distant observable cosmological "objects"?

2) Is it speculated that Quasars more or less spherically encompass the most outer "edges" of our universe? Not close to each other of course.

3) Has a Quasar even been observed that is "closer" than the "outer-edges" of our universe? That is, has a Quasar been observed that a galaxy is found to be "farther"?

4) Do Quasars exist NOW? That is, since it takes such a long time for light to reach us, and of the fact that some very distant stars that we see in the night sky no longer actually exist, do(or can) Quasars "die"?

Thank you.

 

[Chronos]

Sorry to jump into this thread with my having little authorative knowledge, but I have a few questions I would like to ask in order for me to more properly understand the "jist" of the comments:

1) Are Quasars currently the most distant observable cosmological "objects"?

2) Is it speculated that Quasars more or less spherically encompass the most outer "edges" of our universe? Not close to each other of course.

3) Has a Quasar even been observed that is "closer" than the "outer-edges" of our universe? That is, has a Quasar been observed that a galaxy is found to be "farther"?

4) Do Quasars exist NOW? That is, since it takes such a long time for light to reach us, and of the fact that some very distant stars that we see in the night sky no longer actually exist, do(or can) Quasars "die"?

Thank you.

1. No, GRB's.

2. No, excepting crackpots.

3. No, excepting crackpots.

4. Unknown. The nearest known quasar is around z = 1.

 

[Nereid]

Nereid, would this post by Space Tiger on the Eddington luminosity of the accretion disc be relevant to your project?

https://www.physicsforums.com/showpost.php?p=937955&postcount=42

Thanks selfAdjoint.

It could help, in the sense that it sets a constraint on one of the actors in the quasar drama (the accretion disk).

OTOH, those constraints may be weak at best, in terms of the variability we will be playing with. Too, there's the question of the role of magnetic fields (ST's envelope had room for only radiation pressure and gravity; a more complete analysis would have to include MHD).

 

[Nereid]

So, Nereird.
what constraints do you feel that a quasar evolutionary theory might have on the Hubble law?

Do you mean the redshift-distance relationship?

 

[Nereid]

quasar evolution, as seen in Hawkins' data?

In the 'time dilation' paper, Fig.1. has two sets of two graphs.

At the handwaving, qualitative level, there is a good story to make re quasar evolution and variability; it goes something like this:

• in the top row, we clearly see that high-z QSOs have more power (= greater variability) than low-z ones, consistent with the idea that the component with the greater/greatest variability declines - in terms of its contribution to the observed optical magnitude - as the QSO evolves
• in the bottom row, we clearly see that the low luminosity QSOs have more power than the high luminosity ones, consistent with the idea that the component with the greater/greatest variability contributes less in high luminosity QSOs
• Perhaps the jet has the greatest variability - it is a smaller component of the total observed light in high luminosity QSOs, and it declines - wrt its relative contribution - as the QSO evolves.

Of course, this idea is nothing more than some words. However, it does give some pointers as to where to look to test it (for example, there are several nearby AGN, with visible jets; some jets can be 'seen' - in the radio if not the optical - almost down to the accretion disk).

 

[Nereid]

4) Do Quasars exist NOW? That is, since it takes such a long time for light to reach us, and of the fact that some very distant stars that we see in the night sky no longer actually exist, do(or can) Quasars "die"?

In http://www.mssl.ucl.ac.uk/www_astro/agn/agn_quasartour.html" , nuclei of Seyfert galaxies, BL Lac objects (blazars), and quasars are all the same kind of thing - SMBH (supermassive black holes) fed by matter via an accretion disk, with polar jets (whose mechanisms for creation and maintenance are not well understood yet), gas clouds in all kinds of trouble ('broad line region) or not ('narrow line region), and a dusty 'molecular torus'.

Perhaps our very own http://www.einstein-online.info/en/spotlights/milkyway_bh/index.html" was once a brilliant quasar?

 

[RandallB]

3) Has a Quasar even been observed that is "closer" than the "outer-edges" of our universe? That is, has a Quasar been observed that a galaxy is found to be "farther"?

4) Do Quasars exist NOW? That is, since it takes such a long time for light to reach us, and of the fact that some very distant stars that we see in the night sky no longer actually exist, do(or can) Quasars "die"?.

3. No, excepting crackpots.

4. Unknown. The nearest known quasar is around z = 1.

I thought Galaxies are observed as far away as z = 2 or 3.
And with some Quasars as close as z = 1, it still left open the possibility of a Quasar being “IN” a galaxy.
Or has this been ruled out?

 

[ratfink]

I thought Galaxies are observed as far away as z = 2 or 3.
And with some Quasars as close as z = 1, it still left open the possibility of a Quasar being “IN” a galaxy.
Or has this been ruled out?

Hi RandallB,
http://ucsdnews.ucsd.edu/newsrel/science/mcquasar.asp"

[Moderator note: the posts that relate to 'the quasar "in" NGC 7319 are now in https://www.physicsforums.com/showthread.php?t=114638".]

 

[Nereid]

I thought Galaxies are observed as far away as z = 2 or 3.
And with some Quasars as close as z = 1, it still left open the possibility of a Quasar being “IN” a galaxy.
Or has this been ruled out?

Both quasars and galaxies have been observed at z > 6.

There are lots of observations of the galaxy 'host' of quasars, going back to the 1960s (it was called 'quasar fuzz' back then). Hubble imaged several, http://hubblesite.org/newscenter/newsdesk/archive/releases/1996/35/" (and there are likely many more such images today).

PhD theses have been written on the properties of quasar hosts - star formation rates, dust, and much more.

If you plug in some relevant key words into the http://adsabs.harvard.edu/abstract_service.html" , you'll get an idea of how much work has been done on the quasar-galaxy relationship.

 

[SpaceTiger]

http://www.stsci.edu/institute/center/information/streaming/archive/STScIScienceColloquiaFall2005/MichaelStrauss110205

Yeah, I know about those results, Michael is my advisor. Several things to consider:

- He's looking at the highest-z quasars, so they can only make rough comparisons. The evolution we're talking about is more subtle.
- They're mostly measuring spectroscopic properties, which tell you more about chemical composition than accretion mechanisms (presumably responsible for the variability).
- They're just getting the tip of the luminosity function at high-z, so the properties of the general population of quasars could still be evolving.
- A survey looking just at the optical variability properties of the SDSS QSOs did find evidence for evolution:

http://xxx.lanl.gov/abs/astro-ph/0310336"

Also, you'll notice that, right after he talks about the lack of evolution in quasar spectra, Michael presents evidence for another of the predictions of the Big Bang Theory: the Gunn-Peterson break. Back at z~6, the universe was more dense and we expect that intergalactic medium would have been more neutral (i.e. less ionized) than today. This fact should manifest itself as increased hydrogen absorption along the line of sight to the quasar and, sure enough, we see this absorption in the highest-redshift quasars.

On a side note, he also discusses how we inferred masses for these, the most luminous quasars, from the Eddington limit, something Garth and I were discussing in the "self-creation" thread.

 

[SpaceTiger]

1. No, GRB's.

I think the current record is held by a galaxy in the Hubble Ultra Deep Field, around z~7. The highest-z GRB that I'm aware of is z=6.24, less than both the most distant quasar and galaxy.

4. Unknown. The nearest known quasar is around z = 1.

It depends on how one defines quasar (versus a "Seyfert"), but the brightest quasar, 3C273, has z=0.158. I don't know if it's still called the nearest.

 

[turbo]

Also, you'll notice that, right after he talks about the lack of evolution in quasar spectra, Michael presents evidence for another of the predictions of the Big Bang Theory: the Gunn-Peterson break. Back at z~6, the universe was more dense and we expect that intergalactic medium would have been more neutral (i.e. less ionized) than today. This fact should manifest itself as increased hydrogen absorption along the line of sight to the quasar and, sure enough, we see this absorption in the highest-redshift quasars.

On a side note, he also discusses how we inferred masses for these, the most luminous quasars, from the Eddington limit, something Garth and I were discussing in the "self-creation" thread.

Thanks for the insights, ST. What if the Gunn-Peterson troughs are caused by accreting neutral hydrogen that has not been sufficiently ionized yet because the quasar's black hole had not managed to accrete enough material energetically enough to produce the EM required to produce the ionization? I'm not as interested in quasars as in gravitation, but I am certain that there are still plenty of mysteries for young go-getters to chase down in this field.

 

[SpaceTiger]

Thanks for the insights, ST. What if the Gunn-Peterson troughs are caused by accreting neutral hydrogen that has not been sufficiently ionized yet because the quasar's black hole had not managed to accrete enough material energetically enough to produce the EM required to produce the ionization?

In order to obtain the observed blueshift relative to the quasar, the material would have to have been expelled toward us at high relativistic velocities. It's hard to imagine a situation in which gas would remain highly neutral after such an expulsion.

I'm not as interested in quasars as in gravitation, but I am certain that there are still plenty of mysteries for young go-getters to chase down in this field.

Always.

 

[Chronos]

I think the current record is held by a galaxy in the Hubble Ultra Deep Field, around z~7. The highest-z GRB that I'm aware of is z=6.24, less than both the most distant quasar and galaxy.

It depends on how one defines quasar (versus a "Seyfert"), but the brightest quasar, 3C273, has z=0.158. I don't know if it's still called the nearest.

Agreed. While GRB's are, as a group, more distant than quasars, I concede the most distant known quasar has a higher redshift [6.4] than the most distant known GRB [6.29]. I had these sources in mind:

Gamma-ray bursts surpass quasars as most distant probes
http://chronicle.uchicago.edu/991104/gamma.shtml

NASA ANNOUNCES DETECTION OF MOST DISTANT EXPLOSION
http://www.nasa.gov/vision/universe/starsgalaxies/2005_distant_grb.html
[re: Visual 6]

You are also correct in pointing out HUDF has catalogued even more remote objects [z~7], and that quasars at Z<1 have been catalogued - e.g., 3C273. I plead the OOM on that count!

 

[turbo]

In order to obtain the observed blueshift relative to the quasar, the material would have to have been expelled toward us at high relativistic velocities. It's hard to imagine a situation in which gas would remain highly neutral after such an expulsion.

A naked BH would have a high redshift relative to the neutral gas surrounding it. There is absolutely no requirement for the H to have been expelled from the BH in order to exhibit a difference in redshift. In fact, I envision just the opposite - that a naked BH may be ejected from a galaxy by gravitational slingshot or by radiation recoil, and begin accreting dust and gas from the IGM. Gradually, the infalling dust and gas heats up enough to ionize larger and larger regions around the BH.

 

[RandallB]

In order to obtain the observed blueshift relative to the quasar, the material would have to have been expelled toward us at high relativistic velocities.

I think I’m beginning to sort out and understand the debate between High z quasars being inside the boundaries of lower z galaxies and options on how that could work vs. seeing them though the galaxy at great distance behind them.

However, I missed the “observed blueshift” involved. Do you know some examples or links that discuss these blueshift observations?
Are blueshifts quantified somehow, like with negative “z” numbers?

 

[SpaceTiger]

A naked BH would have a high redshift relative to the neutral gas surrounding it. There is absolutely no requirement for the H to have been expelled from the BH in order to exhibit a difference in redshift. In fact, I envision just the opposite - that a naked BH may be ejected from a galaxy by gravitational slingshot or by radiation recoil, and begin accreting dust and gas from the IGM. Gradually, the infalling dust and gas heats up enough to ionize larger and larger regions around the BH.

A giant black hole cannot be given a slingshot to relativistic velocities, it's just not dynamically possible.

 

[SpaceTiger]

However, I missed the “observed blueshift” involved. Do you know some examples or links that discuss these blueshift observations?
Are blueshifts quantified somehow, like with negative “z” numbers?

Blueshifted relative to the quasar, not our rest frame. In other words, we see the quasar at a very large distance (high redshift). Between us and the quasar is neutral gas that absorbs some of the light from the quasar. Since it's not as far away, this gas will absorb at a wavelength that is blueshifted relative to the quasar frame.

 

[RandallB]

Blueshifted relative to the quasar, not our rest frame. In other words, we see the quasar at a very large distance (high redshift). Between us and the quasar is neutral gas that absorbs some of the light from the quasar. Since it's not as far away, this gas will absorb at a wavelength that is blueshifted relative to the quasar frame.

Then we must observe this as missing light spectra it the light we see in our reference frame. Then by adjusting that spectra, back to a reference frame of the quasar must shows a blue shift required with the local gas in the host galaxy in order to match the know gas naturally available to account for the absorption lines we see.

I guess I can see how we can make those observations.

Do you know if there is a correlation to the blue shift related to the “z speeds”?
Like Host z = 3 minis Quasar z = 9 giving something like a blue shift of “-4 or -5” z, or some other measure of blueshift?

 

[turbo]

A giant black hole cannot be given a slingshot to relativistic velocities, it's just not dynamically possible.

Who said that quasars are moving at relativistic velocities? Certainly not me. It's my undersatanding that, depending of the mass of the host galaxy, the ejection velocity may only need to be a few hundred km/s.

 

[SpaceTiger]

Who said that quasars are moving at relativistic velocities? Certainly not me. It's my undersatanding that, depending of the mass of the host galaxy, the ejection velocity may only need to be a few hundred km/s.

The effective velocity difference between the neutral hydrogen and quasar can be thousands of kilometers per second. I don't know what you're referring to. Do you have a reference?

 

[Nereid]

A naked BH would have a high redshift relative to the neutral gas surrounding it. There is absolutely no requirement for the H to have been expelled from the BH in order to exhibit a difference in redshift. In fact, I envision just the opposite - that a naked BH may be ejected from a galaxy by gravitational slingshot or by radiation recoil, and begin accreting dust and gas from the IGM. Gradually, the infalling dust and gas heats up enough to ionize larger and larger regions around the BH.

Leaving aside how the 'naked BH' got to be alone in the IGM, no matter how it accreted anything (baryonic), there's no way we, here on Earth, could observe the accreting gas as having a redshift that had a gravitational component (except, perhaps, if we could watch a 'blob' falling in, and could resolve very broad lines) - the EM from any such accreting gas would be detectable, but if it were close enough to the BH that it had even a quite modest gravitational redshift, we couldn't measure that redshift (the lines would be broadened too much).

 

[ratfink]

Second - Hawkins has published other papers on his favourite explanation for the phenomenom - http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1996MNRAS.278..787H&amp;data_type=PDF_HIGH&amp;type=PRINTER&amp;filetype=.pdf he argued that this effect, along with a number of other properties of the light curves, are best explained by gravitational microlensing of the quasar continuum region. A population of Jupiter sized primordial BHs with a total density contribution of $\Omega_{BHs} = 0.1$, (i.e. not baryonic matter) is responsible.

but you still have the problem that the further away the quasar the faster it must blink otherwise you would end up with time dilation effects - and one doesn't.

Not such an outlandish suggestion after all!

In which case you have to explain why distant SN and (apparently) long GRBs do exhibit time dilation.

Garth

No, they do not exhibit time dilation - the light curves are 'stretched'. Time dilation is a possible explanation of this. In any case, have you seen the errors in this? A static universe was 'disproved' but only at the 3 sigma level!

 

[SpaceTiger]

No, they do not exhibit time dilation - the light curves are 'stretched'. Time dilation is a possible explanation of this. In any case, have you seen the errors in this? A static universe was 'disproved' but only at the 3 sigma level!

I'm just dying to hear your theory for the CMB.

 

[ratfink]

You will have to wait - off topic (BTW did the latest WMAP stuff confirm the axis of evil?)

 

[SpaceTiger]

You will have to wait

That was sarcasm. If you have a personal theory, it belongs in IR.

off topic (BTW did the latest WMAP stuff confirm the axis of evil?)

It's not as significant as before, but it's still there. The WMAP team feels that the arguments concerning the "axis of evil" are too a posteriori to be of much use. That's always been my feeling as well. If you want to discuss it, please feel free to bring it up in the WMAP thread.