Quasars occurred throughout the early universe but only while there was a lot of gas around to fall into the central black holes. Most of it has been used up so that's why we don't see them nearby, you have to look far away to see earlier times.

They are complex structures and send jets of material out from the poles of the rotating accretion disc but look different if we are not in that direction.

   According to General Relativity, our visible universe is a 4-dimensional manifold, but we sit on a 3-dimensional submanifold. In one less dimensión, we sit on the surface of an expanding balloon (that is, if you accept the expanding-universo picture). An ant sitting on such a balloon will see every other ant moving away from her (according to Hubble's law, incidentally).  

   This is the standard explanation (which I support).

Hi George Dishman

"Quasars occurred throughout the early universe", is just a kind of naive justification to explain why Quasars are high redshifted. If this is true, what is process permits the formation of the Quasars at early universe and prevents such formation now?

Hi Salah,

I explained in my previous post: ".. only while there was a lot of gas around to fall into the central black holes. Most of it has been used up so that's why we don't see them nearby, you have to look far away to see earlier times."

We do see galactic nuclei become active nearby but not very often. Look at our own galactic core and you can see a few stars in very elliptical orbits passing close to the SMBH but none have hit it yet. In the early universe, SMBH were able to pull in material at a rate equivalent to several solar masses per year.

Salah, your question really hits the nail on the head. The standard explanation for quasars cannot account either for the extreme energetics and relativistic outflows of charged particles or for the extinction of quasars during the early universe. This is particularly puzzling within the quiescent cores of galaxies in nearby galaxy clusters. There, gas starvation definitely cannot be the cause of quasar death. Only about 10% of the original gas has been reprocessed so far in clusters. A solution does exist, however. It challenges the dogma of recent generations - but don't let that bother you too much as it suggests yet another success for Einstein.

Preprint Dispelling Black Hole Pathologies Through Theory and Observation

Hi Robin

Yes, the scenario concering the Quasars no more than speculations and guesses to fabricate suitable explaination to current observations. The problem relies on the simliarity of the cosmological redshift to the Doppler redshift that both of them cause recession speed. The first by the expansion of the spacetime and other by receding withen the spacetime. If the high redshift of the Quasar is due to the cosmological redshift of the expanding spacetime, why shouldn't agree and concide with the redshift of the hosting Galaxy. The cosmological redshift must be interpreted in a different way, as I do, as manifests the curvature of the hyperbolic spacetime.

Article Title: The Cosmological Redshift Manifests the Curvature and...

SM: If the high redshift of the Quasar is due to the cosmological redshift of the expanding spacetime, why shouldn't agree and concide with the redshift of the hosting Galaxy.

In many cases the host galaxy is too dim to be seen but where both can be measured, they do agree.

Hi George

No, they don't agree. The high redshifts of the Quasars reflect a recession speed approches and exceed the speed of light, where those of Galaxies is very low compared to the Quasars..

At present, the most distant known galaxy with a spectroscopic redshift is EGSY8p7. That has a redshift of z=8.68 corresponding to a recession speed of 3.65c at the time the light was emitted (2.1c now). The most distant quasar is ULAS J1120+0641 with a redshift of 7.085 corresponding to a recession speed of 3.17c at the time the light was emitted (2.0c now).

However, those are unrelated objects. Can you back up your claim by providing an example of a quasar at the centre of a host galaxy with a significantly different redshift?

https://en.wikipedia.org/wiki/EGSY8p7

https://en.wikipedia.org/wiki/ULAS_J1120%2B0641

The bright the Quasar the high the redshift the distant is. The bright the Galaxy the low redshift the nearby is. Brightest Galaxies associated with brightest Quasars, but faint Galaxies not. So, if a Quasar agree in their brightness they disagree with their redshifts.

AK: couldn't quasars have cosmological and gravitational redshifts superimposed?

Yes, generally they will but the amount of gravitational redshift would depend only on the mass and how far from the central black hole the light is generated. For a large accretion disc, that can be quite far out so the shift is small.

Salah, the brightness of the quasar depends on the rate at which material is falling onto the accretion disc and the exact orientation of the disc with respect to our line of sight so it varies over a very large range.

There is also the little matter of how an electrically neutral black hole can launch relativistic jets away from itself. Isn't gravity a force of attraction? A proper scientific model must be able to account for all the observed characteristics of quasars, not just those that fit one's pet theory. The accretion disks of black holes are made of plasma at searing temperatures, way above the Curie temperatures of ferromagnets. The claim that the accretion disk becomes gradually magnetised over millions of years is ludicrous. A model that fits all the facts, however inconvenient they may be to the establishment, has been proposed:

Article Quasars: A supermassive rotating toroidal black hole interpretation

Preprint Dispelling Black Hole Pathologies Through Theory and Observation

Ah, an electrically neutral BH produces a magnetic field, now it all makes sense!

For the same reason as a spheroidal BH is expected to be electrically neutral, a plasma will normally be electrically neutral on macroscopic scales. That is why astrophysicists do not claim that accretion disks are initially magnetised. Instead, we are invited to believe that the magnetisation takes hundreds of millions of years to accumulate. Yet quasar luminosity can vary enormously on timescales of hours.

Aleš, bear in mind that even the innermost edge of the disc can be no closer than 3 times the Schwarzschild Radius, that's the innermost stable circular orbit (ISCO).

I've linked a slide set from a Caltech course, have a look at how the disc spectrum is built up on slide 24 which includes gravitational redshift and compare it with the real example on slide 25.

http://www.astro.caltech.edu/~george/ay127/Ay127_AGN.pdf

Ales, have you ever wondered what would happen to the charged particles of a plasma if they were actually capable of crossing a black hole event horizon? Ever wondered what might become of their magnetic fields out here in the real world?

Ales, I take it that your black hole would also have formed through time tunneling then. Can tunneling of some kind eradicate electrical charge from the universe? Can it allow the total entropy of the universe to decrease? Can it bring Einstein back to life so he can knock science back into shape?

I think the point that is missed in these remarks is that the observable properties of quasars come entirely from the accretion disc whose inner edge is well outside any event horizon, whether that exists or not.

We have no more than guesses and speculations, then we built upon them theory which soon collapses. No direct observations nor rigours  mathematics.

That is simply not true. The slides I cited earlier are just an overview for a lecture to undergraduates but the plots included are from scientific papers where the modelled spectra were calculated and matched to the observed spectra. The modelling is complex and evolving but the basics are all solid.

Ales

Your guess is correct, the gravitational redshift of the Quasar manifests the curvature ,

TDM: One should not mix up the quasars that are the result of accumulated ejected material from jets, and the BH's with acretion disks that likely were formerly binary stars.

The sizes are very different of course but the main features, discs and jets, are similar.

Jet material does slow until the shock of hitting previously ejected material slows it to a stop creating the well known "lobes", but other than the Doppler shift of the high speed jets, the redshifts are similar to the host galaxies. Arp did some great work but also reached some poor conclusions because he was working mainly with photographic plates. Modern detectors and space-based telescopes showed that many of his "associations" were completely unrelated objects merely sharing a line of sight to us.

“Quasar light curves do not show the effects of time dilation” - this result of seems incredible. The cosmological time dilation is very basic phenomenon predicted by the Friedmann-Robertson-Walker (FRW) metric.

How can quasars ignore this fundamental effect of relativistic cosmology?

Mainstream cosmologists simply ignore the evidence supporting association of objects with different redshifts considering all these cases as a just random projections of background objects like constellations. They might be righ in some cases but the statistics of anomalies seems to be too high to indicate that we do not completely understand these phenomena. To conclude, at present we have no compelling reason to reject the standard cosmological concepts about quasars. However, it seems that there is a growing number of alleged observational facts which are difficult to reconcile with the standard paradigm. It is not a good strategy to simply ignore these facts, in our opinion. It would be much better to remember the nineteenth century humorist Josh Billings’ aphorism “It ain’t ignorance causes so much trouble; it’s folks knowing so much that ain’t so” [74] and keep eyes wide open to new insights.

The high redshifts of the quasars imply they are distant. Hence they are younger. Therefore, quasars should be deficient in metals. But observations show no metal deficiency as a function of redshift. Quasars enviroments, based on their emission lines, are generally metal rich with metallicities near or above the solar value.

Robin Spivey. added an answer on February 26, 2016:

Salah, your question really hits the nail on the head. The standard explanation for quasars cannot account either for the extreme energetics and relativistic outflows of charged particles or for the extinction of quasars during the early universe.

This is particularly puzzling within the quiescent cores of galaxies in nearby galaxy clusters. There, gas starvation definitely cannot be the cause of quasar death. Only about 10% of the original gas has been reprocessed so far in clusters.

A solution does exist, however. It challenges the dogma of recent generations - but don't let that bother you too much as it suggests yet another success for Einstein.

Article Dispelling Black Hole Pathologies Through Theory and Observation

Recommended / Share

• 2 Recommendations

Salah A. Mabkhout. added an answer on February 29, 2016

Hi Robin,

Yes, the scenario concerning the Quasars is no more than speculations and guesses to fabricate suitable explanation to current observations. The problem relies on the similarity of the cosmological red-shift to the Doppler red-shift that both of them cause recession speed. The first by the expansion of the spacetime and other by receding within the spacetime. If the high red-shift of the Quasar is due to the cosmological red-shift of the expanding spacetime, why shouldn't [this] agree and coincide with the red-shift of the hosting Galaxy. The cosmological red-shift must be interpreted in a different way, as I do, as manifests the curvature of the hyperbolic spacetime.

Article Title: The Cosmological Redshift Manifests the Curvature and...

Recommended / Share

• 1 Recommendation

Robin Spivey. added an answer on March 1, 2016:

There is also the little matter of how an electrically neutral black hole can launch relativistic jets away from itself. Isn't gravity a force of attraction? A proper scientific model must be able to account for all the observed characteristics of quasars, not just those that fit one's pet theory.

The accretion disks of black holes are made of plasma at searing temperatures, way above the Curie temperatures of ferromagnets. The claim that the accretion disk becomes gradually magnetised over millions of years is ludicrous. A model that fits all the facts, however inconvenient they may be to the establishment, has been proposed:

Article Quasars: A supermassive rotating toroidal black hole interpretationArticle Dispelling Black Hole Pathologies Through Theory and Observation

Recommended / Share

• 2 Recommendations

George Dishman. added an answer on March 2, 2016:

Aleš, bear in mind that even the innermost edge of the disc can be no closer than 3 times the Schwarzschild Radius, that's the innermost stable circular orbit (ISCO).I've linked a slide set from a Caltech course, have a look at how the disc spectrum is built up on slide 24 which includes gravitational redshift and compare it with the real example on slide 25.http://www.astro.caltech.edu/~george/ay127/Ay127_AGN.pdf

Recommended / Share

• 2 Recommendations