Quasars are the Waterloo of LCDM theory.....

[Michael]

Yep .. I agree and I suspect the armchair cranks will also never allow him to change his initial views on possible causes either (because they're addicted to all the 'good bits'!?)

I couldn't speak for the "cranks", but I would definitely allow him to change his initial views on the possible causes because his first so called 'explanation' is utterly ridiculous. Talk about faith in miracles. What are the odds that light from every single quasar experiences microlensing, yet light from every SN1A event does not? That's an absolutely absurd proposition.

There have been so many survey papers since, its hard to name them all here!

A single published paper that actually showed clear evidence of time dilation from quasars would do. Go ahead, make my day.

It's not like your supernatural creation dogma doesn't fail a half dozen other high z observational "tests", but it fails the quasar time dilation test in truly *epic* fashion. The only explanation offered by the author of the paper to explain that lack of time dilation could only be called the "miraculous alignment hypothesis".

 

[Michael]

Quasar jet streams are 100 times hotter than thought possible at 10 TRILLION degrees | Daily Mail Online

Every so often, astronomers make a discovery that goes against everything they thought before.

These kind of discoveries are the most exciting because they lead the way to new physics and, ultimately, a better understanding of the universe.

The most recent example of such a discovery is a quasar jet that turns out to be 100 times hotter than was considered the maximum of such objects at 10 trillion degrees Kelvin.

Quasars really are LCDM's Waterloo. Your creation mythology is so full of holes it's not even funny.

 

[sjastro]

Yep .. sure.

There's a plethora of ideas about causes including instabilities in the accretion disk, supernovae influences(?), Hawkins' microlensing, stellar collisions, thermal fluctuations from magnetic field turbulence and other generalised 'Poisson' processes (whatever they might be .?.))

The Poisson processes probably relate to two main factors.
(1) The statistical nature of light.
The number of photons hitting a detector varies statistically, the deviation from the average allows sigma to be calculated which as we know is a measurement of statistical noise.
(2) Electronic or shot noise.
When photons hit the detector the resultant current varies which is also statistical in nature.

When determining the light curves from faint objects such a quasars its important to have deep exposures in order to have high S/N ratios otherwise the Poisson or statistical noise can lead to photometric errors.

This is analogous to your coin tossing exercise which as we know led to the astounding 1=0.5 derivation.

I'm interested .. feel free to go ahead (if you can find some spare time .. much appreciated).

I'll prepare it some time tomorrow.

 

[Michael]

This is analogous to your coin tossing exercise which as we know led to the astounding 1=0.5 derivation.

"Lies, lies, lies, yeah........"

You really do shoot your own credibility in the foot, not that you had any to start with.

I'm still waiting to see a published paper that claimed to show evidence of time dilation from quasars.

I can see now why Arp focused on such objects. They utterly destroy your model.

 

[sjastro]

I'm interested .. feel free to go ahead (if you can find some spare time .. much appreciated).

The mathematics of cosmological time dilation and the corresponding physical interpretation is as follows.
It’s assumed the reader is familiar with the concept of a metric in space-time, if not it is discussed here.

The metric for an expanding Universe is known as the Robertson-Walker (RW) metric which is a solution for Einstein’s field equations and is defined as:

a(t) is the scale factor and is defined as

r(t) is the radius of the Universe at some point in the past at a cosmological time t.
r(t₀) is the radius of the Universe today at time t₀.
Note that current scale of the Universe is:

σ is the comoving coordinate where expansion is factored out.
The comoving distance between two galaxies is therefore a constant in an expanding Universe assuming each galaxy does not have a peculiar velocity or independent motion through space-time.

k is a discrete variable that defines the geometry of the Universe.
If k = 0 the Universe is flat with zero curvature.
If k = 1 the Universe is closed with positive curvature.
If k = -1 the Universe is open with negative curvature.

θ and φ are the polar and azimuthal angles associated with spherical coordinates.

Let’s consider photons emitted from a galaxy on a trajectory with constant θ and φ.
Since θ and φ are constant dθ = dφ = 0.
As light travels along a null geodesic, the time and spatial components are equal hence ds² = 0.
The RW metric reduces to the simple equation.

Suppose two photons are emitted from a galaxy separated by the time interval Δt₁ and reach an observer in our galaxy at the present cosmological time t₀.
For the first photon emitted at time t₁ and reaching the observer at time t₀:

The second photon is emitted at t₁+Δt₁ and reaching the observer at time t₀+Δt₀.

When the above two equations are subtracted we obtain.

The first integral can be broken up into separate components which give:

And reduce to:

In the photons local frame of reference the photons are separated at a scale where expansion is negligible.
We can therefore treat a(t) as a constant and integrating the above equation gives.

Since a(t₀)=1

This equation tells us in the photon’s “rest frame” the time interval between emissions is Δt₁ but an observer in our galaxy measures the time difference as Δt₀.
Since a(t₁)<1 then Δt₀>Δt₁ hence the observer will always measure a longer time interval which is stretched or cosmologically time dilated in his frame of reference.

The physical reason for cosmological time dilation is that during the photons journey to the observer, the Universe has expanded in the time it takes the photons to reach the observer.
Since photons travel along null geodesics the separation between the photons increases as the Universe expands and the observer will therefore measure a longer time interval.

 

[SelfSim]

The metric for an expanding Universe is known as the Robertson-Walker (RW) metric which is a solution for Einstein’s field equations and is defined as:

a(t) is the scale factor and is defined as

r(t) is the radius of the Universe at some point in the past at a cosmological time t.
r(t₀) is the radius of the Universe today at time t₀.
...
Since a(t₁)<1 then Δt₀>Δt₁ hence the observer will always measure a longer time interval which is stretched or cosmologically time dilated in his frame of reference.

The physical reason for cosmological time dilation is that during the photons journey to the observer, the Universe has expanded in the time it takes the photons to reach the observer.
Since photons travel along null geodesics the separation between the photons increases as the Universe expands and the observer will therefore measure a longer time interval.

So what we have here is an exact solution to the Einstein Field equations, (EFEs), out of which falls time dilation as a logical consequence ..

Clearly, its not quite rational to:

i) 'agree' with Einstein's GR;
ii) 'disagree' with an expanding universe (even though it is an exact solution to the EFEs .. with supporting Supernova redshift and dilation measurements), whilst;
iii) supporting the concept of an apparent unobservability of time dilation in only intrinsically complex QSOs, (quasars), as direct evidence against an expanding universe whilst;
iv) questioning the sanity of an author (Hawkins) who accepts ruling out a non-expanding universe, (solely because said author chooses to pursue other physically known (evidenced) mechanisms)?

Oh .. and by the way: "Happy Dark Matter Day" to all! (Isn't it just a wonderful celebration?)!
(Apologies for being a day or so late .. )

 

[Michael]

So what we have here is an exact solution to the Einstein Field equations, (EFEs), out of which falls time dilation as a logical consequence ..

And what we don't have here is specifically what I asked you two for, namely a published study that actually shows that quasars *do* show any evidence of time dilation. You two seem to be going to great lengths to avoid the fact that you have zero evidence to support the concept that the most distant and powerful objects show evidence of time dilation, and I've already provided you with one paper that shows that they *don't*.

Clearly, its not quite rational to:

I love how two guys who's belief system is composed of 95 percent placeholder terms for human ignorance, combined with about 5 percent "pseudoscience" feel compelled to lecture me about what might be 'rational' and what isn't. It's so cute. Nothing like failing a half dozen different "tests" and then going to the teacher and telling them that the F that they gave you isn't rational.

i) 'agree' with Einstein's GR;

I'm fine with GR theory itself. While it's mathematically possible to stuff magic into a GR formula, GR is *not* dependent upon magic, dark energy, dark matter, space expansion or inflation. You're stuffing four *optional* (non required) elements into a GR formula that really have little or nothing to do with GR theory other than the fact that you chose to stuff them into a GR formula. LCDM is *not* GR theory. In fact it's at least 95 percent *not* GR theory.

ii) 'disagree' with an expanding universe (even though it is an exact solution to the EFEs ..

I have no doubt that GR theory can be used to describe an expanding universe, a contracting universe or even a static universe. Only one of those universes actually exists however. I don't have to agree that it's doing all three. Only one of those scenarios describes the actual universe we live in.

with supporting Supernova redshift and dilation measurements), whilst;

You've already got one serious problem with that claim. You claim that simply because the signal has been "broadened" over distance that this automatically equates to "time dilation" when in fact it could also simply demonstrate ordinary signal broadening in a medium as described by pretty much every "tired light" theory under the sun, and as we observe in the lab. Light pulses spread out over distance as they travel down a fiber optic cable too. Signal broadening is also a logical explanation for a stretched out signal from SN1A events.

viXra.org e-Print archive, Lyndon Ashmore

If the cause of that stretching of the singal was actually "time dilation" then we should see evidence of time dilation in *all* distant objects, not just 'special" types of "one off' events, based upon the *assumption* that they are "standard candles", when in fact we now have evidence that they are not as standard as you originally claimed! Talk about irrational premises! Holy cow!

Supernova 'standard candles' not so standard after all | Cosmos

Even the core premise/assumption of your SN1A claims has been *falsified*!

iii) supporting the concept of an apparent unobservability of time dilation in only intrinsically complex QSOs, (quasars), as direct evidence against an expanding universe whilst;

If time dilation was the real cause of the signal broadening that we observe, then it should be present in quasars too. If it's only observed in specific types of events and not others, where's the evidence that it's actually caused by time dilation, and not ordinary signal broadening in a plasma medium?

It's not as though you've dealt with any of those *other* problems (failed tests) that you have in high z value observations, or the other "failed tests" of your theory in the lab! When you put them altogether and look at them as a whole, we don't see evidence of galaxy evolution as you claim, we don't see evidence of a reionization process as you predicted. We see evidence of massive black holes that don't fit your theory. We see "dusty" galaxies as far back in time as we can observe, and there's literally no reason to believe that your theory is accurate. On top of all that conflicting evidence, we also have several billion dollars of failed tests of your dark matter claims, and ample evidence that you've been consistently and seriously underestimating the mass of galaxies based on their photon output. Worse yet, you didn't know where most of the mass of the galaxies resided until 2012, and you didn't know about the neutral hydrogen gas halo until *this year*!

iv) questioning the sanity of an author (Hawkins) who accepts ruling out a non-expanding universe, (solely because said author chooses to pursue other physically known (evidenced) mechanisms)?

I dared to question miraculous lensing 900 times in a row? How is miraculous positioning/lensing a "known mechanism"? I'd buy that idea if only a few of the events didn't show evidence but the rest did, but *none* of them show any evidence of time dilation. On one hand you're claiming that several hundred SN1A events show none of the signs of this magical special lensing process, but 900 quasars just so happen to be positioned *exactly perfectly* to cancel out time dilation? I thought you two didn't believe in "miracles"?

I didn't question Hawkin's sanity by the way, I questioned his handwavy 'excuse' as to why quasars show no signs of time dilation. The fact that neither of you has come up with any paper that suggests they *do* experience time dilation, or any other 'rational' explanation for *any* of the problems I've mentioned in this thread simply makes that claim look ridiculous. You'd need 900 *perfect* alignment processes to take place for that particular explanation to be valid. I simply lack belief that it's a 'rational' explanation for the lack of time dilation from 900 different objects.

If an EU/PC proponent proposed something that ridiculously unlikely as the cause of their failed prediction, you'd call them a "crackpot", a "crank", yada, yada, yada.

Oh .. and by the way: "Happy Dark Matter Day" to all! (Isn't it just a wonderful celebration?)!
(Apologies for being a day or so late .. )

Based on the LHC, LUX, Zenon-1T and PandaX experiments it is rather obvious that dark matter is a magic trick, not an empirical physics treat. That is why LHC has destroyed all of your most "popular" mathematical models, and that's why LHC demonstrated that the standard particle physics model predicts the various lab results that we've observed with *stunning* accuracy.

The whole basis for your astronomical "evidence" for dark matter has been *obliterated* by later studies which show that your horrifically flawed 2006 lensing study underestimated the brightness of galaxies by a factor of 2. It underestimated the number of stars in various galaxies by a whopping factor of between 3 and 20 times depending on the size of the star and the type of galaxy, and it didn't include either of the two different "halos" of hot plasma or cool gas that we've found since 2012 which contain more mass than all the mass of the stars combined!

Thunderbolts Forum • View topic - Lambda-CDM - EU/PC Theory - Confirmation Bias

At least they picked the right day to call it "dark matter day". It's clearly a magic "trick", not a physics treat.

 

[Michael]

You two are going to great lengths to avoid what I asked you for, specifically a quasar study that shows evidence of time dilation from those objects. All I've seen thus far is a paper that doesn't mention Hawkins work or his paper to start with. It doesn't demonstrate any mistakes in his work, and doesn't mention the term 'time dilation' even once in the whole paper. It's not even a valid rebuttal of Hawkins paper!

Let's recap now.

We spent billions of dollars in the lab looking for exotic forms of matter and we've found exactly nothing to support your wild assertion about the existence of exotic matter. Meanwhile the standard particle physics model has been demonstrated to predict those same lab results with *stunning* accuracy.

Your expansion model fails the surface brightness test at larger redshifts.

Your model fails to explain those 12 billion solar mass 'black holes' at the highest redshifts.

Your model fails the quasar time dilation test.

Your model fails the 'galaxy evolution' test.

Your model fails the "reionization" test too.

On the other hand a static universe/tired light model is consistent with all of those same observations.

About the only 'evidence" you seem to be able to produce to support an expansion model is related specifically to a narrow microwave bandwidth which Eddington first *predicted* based on the simple process of the scattering of starlight off the dust of spacetime, and he nailed the right number to within 1/2 of one degree on his first try. Early estimates based on expansion models were off by more than a whole order of magnitude and it took them three of four tries to get any closer than Eddington at predicting the average temperature of spacetime.

Worse yet, the only way you can actually get a "match" to even those observation is to insert 95 percent ad hoc constructs, one of which has failed billions of dollars worth of lab tests! Notice a problem?

 

[Michael]

The physical reason for cosmological time dilation is that during the photons journey to the observer, the Universe has expanded in the time it takes the photons to reach the observer.
Since photons travel along null geodesics the separation between the photons increases as the Universe expands and the observer will therefore measure a longer time interval.

Very nice explanation of time dilation. Now all you need to do is to produce a quasar study that actually demonstrates that quasars show evidence of time dilation as I requested.

 

[sjastro]

A further expansion of the maths in my previous post is to show the relationship between redshift z and cosmological time dilation.

Light is also subject to the scaling a(t) as evidenced by cosmological redshift where wavelength increases, therefore:

In this case λ and λ₀ are the wavelengths at cosmological time t and t₀ respectively.

The redshift z is defined as.

However as shown in my previous post.

Where Δt is the time interval in the rest frame, Δt₀ is time interval in the observer frame.

Therefore the equation becomes:

A picture using actual data tells a thousand words to illustrate the maths.

 

[Michael]

Readers should note that we have still seen nothing remotely resembling a legitimate scientific rebuttal to Hawkin's observations of a complete lack of time dilation in quasars, nor any other published paper which claims to observe time dilation in quasars.

I'm starting to believe that this nifty little mathematical exercise is simply another clever form of denial. I think they believe that if they can explain how the process *should* work, nobody will notice that it *doesn't actually work*.

As the other links in this thread also demonstrate, astronomers can't even explain the heat source of the plasma jets around quasars either, mostly because they refuse to embrace electric fields and current flow in spacetime. Astronomers today are completely and totally electrophobic when it comes to cosmology. They're like the keystone cops of physics, but boy can do they do metaphysical math exercises.

FYI, "space expansion", like "dark magic", can of course be stuffed into a GR formula, but it's *entirely optional* and GR is in no way *dependent* upon such concepts.

Are either of you planning to post an actual rebuttal to Hawkins work, or shall I assume that you can't find a scientific rebuttal to his findings?

It's not like LCDM doesn't fail at least a half dozen other long distance, high redshift predictions, including failing the surface brightness tests, tests of their reionization claims, supermassive black hole problems, mature galaxy problems, etc. It's just that LCDM fails the quasar time dilation test in truly *epic* fashion, so they talk all around the edges of the problem without actually dealing with the problem.

Make no mistake about it, LCDM offers no real 'knowledge' to start with because 95 percent of it amounts to placeholder terms for human ignorance and most of the rest of their math which they apply to plasma amounts to "pseudoscience" according to the author of MHD theory. The whole LCDM model is utterly and entirely devoid of any type of real "knowledge" which is why none of it actually works in the lab.

We spent billions looking for dark matter and found nothing. Their model fails tons of observational tests too, but they simply sweep all their failures right under the rug and pretend they don't exist. The only thing holding LCDM together in 2017 is pure denial.

 

[SelfSim]

A further expansion of the maths in my previous post is to show the relationship between redshift z and cosmological time dilation.

Light is also subject to the scaling a(t) as evidenced by cosmological redshift where wavelength increases, therefore:

In this case λ and λ₀ are the wavelengths at cosmological time t and t₀ respectively.

The redshift z is defined as.

However as shown in my previous post.

Where Δt is the time interval in the rest frame, Δt₀ is time interval in the observer frame.

Therefore the equation becomes:

A picture using actual data tells a thousand words to illustrate the maths.

Hmm .. interesting. Thank you for spending the time and effort to demonstrate how the explicit relationships are derived from the generalised Einstein GR models and then, comparing the predictions with real SN measured data.

Keeping the empirical relationships and the diagram in mind, the interesting question arises of what impacts might the doppler/redshift issues have in more distant quasar type light curves, then?

This recent (like within the days few days) study, throws some interesting light on the matter:
NEW METHOD FOR RESEARCHING ACTIVITY AROUND QUASARS AND BLACK HOLES
(My emboldenment):

For decades, astronomers have been studying the light coming from AGNs to determine how large and massive their black holes are. This has been difficult, since this light is subject to the Doppler effect, which causes its spectral lines to broaden. But thanks to a new model developed by researchers from China and the US, astronomers may be able to study these Broad Line Regions (BLRs) and make more accurate estimates about the mass of black holes.

They then say:

The problem with observing these bright regions comes from the fact that the gases within them are moving so quickly in different directions. Whereas gas moving away (relative to us) is shifted towards the red end of the spectrum, gas that is moving towards us is shifted towards the blue end. This is what leads to a Broad Line Region, where the spectrum of the emitted light becomes more like a spiral, making accurate readings difficult to obtain.

Paper here.
If mass calculation is plagued by such reading uncertainties, then how might the time dilation parameter be affected?

 

[Michael]

Hmm .. interesting. Thank you for spending the time and effort to demonstrate how the explicit relationships are derived from the generalised Einstein GR models and then, comparing the predictions with real SN measured data.

Er, you mean "metaphysicalized LCDM models" because space doesn't do any magic expansion tricks in the lab, around the Earth, or anywhere in the whole galaxy, cluster or supercluster, and GR doesn't require it in the first place. The "space expansion" claim is nothing more than an "act of pure faith" in metaphysical processes on the part of the believer. Why are you guys atheists again when you put so much faith in numerous metaphysical claims?

If mass calculation is plagued by such reading uncertainties, then how might the time dilation parameter be affected?

It's worse than you think. Your mathematical models of quasars are *so* uncertain and so primitive, you underestimated the plasma jet temperatures by two who orders of magnitude. Yep, that's a pretty serious problem alright.

Your industry has a really bad case of electrophobia and none of those quasar observations can be explained without overcoming your fear of acknowledging the role of electricity in space.

 

[sjastro]

Hmm .. interesting. Thank you for spending the time and effort to demonstrate how the explicit relationships are derived from the generalised Einstein GR models and then, comparing the predictions with real SN measured data.

Keeping the empirical relationships and the diagram in mind, the interesting question arises of what impacts might the doppler/redshift issues have in more distant quasar type light curves, then?

This recent (like within the days few days) study, throws some interesting light on the matter:
NEW METHOD FOR RESEARCHING ACTIVITY AROUND QUASARS AND BLACK HOLES
(My emboldenment):
They then say:Paper here.
If mass calculation is plagued by such reading uncertainties, then how might the time dilation parameter be affected?

I don’t think the mass calculation is a pivotal issue.

The paper deals with a mechanism which is an addition to current thinking that the relativistic beaming of the jets and the inefficient conversion of gravitational potential energy of the accretion disk into EM radiation contribute to the variable light output of quasars.

This mechanism involving the tearing off clumps of matter which fuel the BH is by its very nature unpredictable and adds to the chaotic nature of the light output.

It simply confirms the extreme difficulty in formulating a template model for the light output variation in the rest frame of a quasar.

Without an accurate template the determination of gravitational time dilation is an extremely difficult exercise if not futile.

 

[Michael]

I don’t think the mass calculation is a pivotal issue.

The paper deals with a mechanism which is an addition to current thinking that the relativistic beaming of the jets and the inefficient conversion of gravitational potential energy of the accretion disk into EM radiation contribute to the variable light output of quasars.

This mechanism involving the tearing off clumps of matter which fuel the BH is by its very nature unpredictable and adds to the chaotic nature of the light output.

It simply confirms the extreme difficulty in formulating a template model for the light output variation in the rest frame of a quasar.

Without an accurate template the determination of gravitational time dilation is an extremely difficult exercise if not futile.

Translation: No Michael, we don't have any published rebuttal of Hawkin's paper, and we have no published paper to offer which reports any observation of time dilation from quasars, so we'll just handwave away and claim that it's really hard to do, without once citing any actual error in Hawkin's work.

Halton Arp was right on the money when he focused on quasars. They don't fit your model in any way, in fact they *defy* your model entirely, and they demonstrate that you don't have a clue how to explain them. You can't even explain why those jets are two whole orders of magnitude hotter than your theories predict.

Your model fails the surface brightness test at larger redshifts, it fails various quasar tests, it fails the maturity of galaxies tests, it fails to explain or predict such massive objects in the early universe, and it fails in terms of predicting the results of billions of dollars worth of laboratory experiments here on Earth in spectacular fashion. The whole model is nothing but metaphysical placeholder terms for human ignorance with a smattering of pseudoscience to begin with!

And you actually wonder why electric universe theory is gaining momentum?

I must say that this has been a very enlightening thread. You folks really have no "knowledge" to offer anyone, just metaphysical dogma galore that doesn't even jive with anything that we actually observe in the distant universe.

LCDM is definitely the laughing stock of physics and it's doomed to be replaced with a new cosmology theory which is based on pure empirical physics sooner or later. I strongly suggest that you two jump ship now, or find a new profession. I'd be embarrassed to call myself a "professional astronomer" while peddling a model that has no useful purpose here on Earth, and no value as it relates to correctly "predicting" anything in the early universe.

I think the jig will be up once the Webb telescope comes online and it returns images of "mature" galaxies as far back in time as it can see. It will be almost impossible at that point to ignore the handwriting on the wall. Your denial song and dance routine is already looking pretty ridiculous and it's only going to get worse over time.

The real back breaker of LCDM is it's need for exotic matter. LHC completed the standard particle physics model and those billion dollar experiments demonstrated that the standard particle physics model correctly predicts the outcome of every observation with absolutely stunning accuracy. It also destroyed all of your metaphysical claims about SUSY theory, and all of your "popular" exotic matter models. You've found nothing at LUX, nothing at PandaX, nothing at Xenon-1T, and nothing in any other experiment that suggests that any form of exotic matter even exists.

Why are you two atheists again? You sure seem to be emotionally and professional attached to all kinds of metaphysical claims, none of which enjoy even a *shred* of empirical support.

It's ironic IMO that you need at least three more metaphysical entities than an average religion.

 

[sjastro]

SelfSim,

We might as well introduce the Hawkins rebuttal paper here from our other discussion.
The use of slopes in Part A of the paper seems incomprehensible but is an extension of the maths I described in post #50.
The trouble with these papers they are written by astrophysicists for astrophysicists and therefore there is no reason to rehash the maths.

Let me fill in the gaps, this is how they did it.
Recall the equation from post #50.

The right hand equation is simply the rate of change of observer time t₀ with respect to rest frame time t.

In terms of the derivative:

The equation becomes.

Using the chain rule:

Here F is the quasar flux measurements as defined in the paper.

Hence the equation becomes:

dF/dt and dF/dt₀ are simply the slopes of the Flux vs Time graphs in the rest and observer frames respectively.
The differences in the slopes are due to cosmological time dilation as the authors have stated.
The measured observer time values for the thirteen quasars have been have been converted into rest frame values by multiplying by 1/(1+z) which is consistent with the first equation in this post.

The obvious question that arises if you can do this conversion why not simply create a rest frame template by multiplying a measured quasar light curve by 1/(1+z) and not worry about slopes.
The trouble is, as has been demonstrated in this thread, Δt₀ varies from cycle to cycle hence the corresponding rest frame value Δt cannot be a unique value which defines the template.
The slopes on the other hand are taken over a number of cycles from thirteen quasars.

So it appears that using this method Quasar 9.5484.258 does in fact exhibit time dilation as its calculated z value from the last equation in this post agrees well with the measured redshift.

Now the next step is to aim for a much larger sample size.

A less technical paper on the subject is found here.

 

[SelfSim]

SelfSim,

We might as well introduce the Hawkins rebuttal paper here from our other discussion.
The use of slopes in Part A of the paper seems incomprehensible but is an extension of the maths I described in post #50.
The trouble with these papers they are written by astrophysicists for astrophysicists and therefore there is no reason to rehash the maths.

Let me fill in the gaps, this is how they did it.
Recall the equation from post #50.

The right hand equation is simply the rate of change of observer time t₀ with respect to rest frame time t.

In terms of the derivative:

The equation becomes.

Using the chain rule:

Here F is the quasar flux measurements as defined in the paper.

Hence the equation becomes:

dF/dt and dF/dt₀ are simply the slopes of the Flux vs Time graphs in the rest and observer frames respectively.
The differences in the slopes are due to cosmological time dilation as the authors have stated.
The measured observer time values for the thirteen quasars have been have been converted into rest frame values by multiplying by 1/(1+z) which is consistent with the first equation in this post.

The obvious question that arises if you can do this conversion why not simply create a rest frame template by multiplying a measured quasar light curve by 1/(1+z) and not worry about slopes.
The trouble is, as has been demonstrated in this thread, Δt₀ varies from cycle to cycle hence the corresponding rest frame value Δt cannot be a unique value which defines the template.
The slopes on the other hand are taken over a number of cycles from thirteen quasars.

So it appears that using this method Quasar 9.5484.258 does in fact exhibit time dilation as its calculated z value from the last equation in this post agrees well with the measured redshift.

Now the next step is to aim for a much larger sample size.

A less technical paper on the subject is found here.

Well that makes more sense .. thanks for that.

So with this paper we do in fact, have refutational evidence from which it appears that some quasars exhibit time dilation .. with a recommendation that more light curves be examined, (ie: beyond the 13 QSOs used in the study).

The paper is some five years old now (published in 2012), so I wonder whether those recommendations were pursued?

Very interesting!

 

[Michael]

SelfSim,

We might as well introduce the Hawkins rebuttal paper here from our other discussion.

Hey, finally a relevant paper! Cool.

In [1], an interesting correlation between emission line equivalent width (the ratio of integrated line flux over local continuum flux density) and rest-frame ultraviolet luminosity was observed. Namely, C IV 1549 A emission-line equivalent width in quasars decreases with increasing UV continuum (1450 A) luminosity.

I'm not exactly clear what they mean by that statement.

We performed our analysis for V-band light curves, though a similar procedure could be carried out for other wavelengths. We currently do not have a theoretical explanation of this effect. We would not want to speculate much on the possible explanation since the physics of these objects is poorly understood.

I've only skimmed the paper thus far. I probably won't get a chance to go through it fully until after work, but it looks like an interesting study, even if I don't begin to grasp the physics of why it might work yet. Then again, it's not clear that the authors themselves have a good explanation for it either. Still, the results look to provide pretty accurate results compared to known redshifts and therefore it does appear to have some merit. It's an interesting paper, but the sample size is pretty small, and the redshift ranges seem somewhat limited. Still, at least it asserts to refute Hawkin's findings and it seems to work quite well on a small sample size.

Now the next step is to aim for a much larger sample size.

Indeed. I'd also be curious to see how well that particular technique works at larger redshifts.

 

[sjastro]

Well that makes more sense .. thanks for that.

So with this paper we do in fact, have refutational evidence from which it appears that some quasars exhibit time dilation .. with a recommendation that more light curves be examined, (ie: beyond the 13 QSOs used in the study).

The paper is some five years old now (published in 2012), so I wonder whether those recommendations were pursued?

Very interesting!

Due to the aperiodic nature of quasars, the observation of their light curves can take years.
All the light curve data comes from the MACHO project which was a long term study of microlensing of background objects such as Quasars by the Large and Small Magellanic Clouds.
This project lasted for seven years and ended in 1999.
Unless there is another similar long term imaging project it's unlikely there will be further additions to the sample size in the near future.

There are long term projects which include current observations combined with old data whether this can expand the sample size remains to be seen.

 

[Michael]

Due to the aperiodic nature of quasars, the observation of their light curves can take years.
All the light curve data comes from the MACHO project which was a long term study of microlensing of background objects such as Quasars by the Large and Small Magellanic Clouds.
This project lasted for seven years and ended in 1999.
Unless there is another similar long term imaging project it's unlikely there will be further additions to the sample size in the near future.

There are long term projects which include current observations combined with old data whether this can expand the sample size remains to be seen.

We wouldn't expect this effect to be limited to micolensed objects so it's really just a question of choice and the allocation of telescope time.