“Black Holes” are considered to be an astronomical fact, based upon the secondary evidence gathered of their existence. According to the theory, as matter is tugged into a black hole, the final acceleration is in the form of an accretion ring that emits radiant energy in the form of x-rays and gamma rays as matter is accelerated into the ‘black hole’ nucleus. Since evidence that an accretion ring in our own galaxy actually exist became quite compelling more than a decade ago, accretion rings activity has been observed in many, many galaxies – so many that it is now kosher to hypothesis that ‘black hole’ features may dominate the centers of all galaxies.

The Tully-Fisher relationship is an equally well-observed phenomena: The total luminosity of a galaxy is directly proportional to the mass fraction, as measured by the estimated size and Newtonian angular velocity of galaxies. The Tully-Fisher relationship is well established, and consistent for galaxies ranging a size-luminosity range factor of over six hundred.

The paradox is obvious: More massive galaxies should, on average, have seen more mass converted to the ‘black hole’ fraction than less massive galaxies. Over time, as more and more mass is consumed by the black hole, the galaxy should become proportionally dimmer as less and less radiant energy is able to excape.

Why then, are more massive galaxies proportional brighter?

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

Galaxy Mergers.

Galaxies have huge gravitational forces and sometimes they will collide when they pass close to another galaxy, they merge and become a much larger galaxy. During the merger thier diffuse gas clouds are compressed together and there is a major amount of new star birth. This adds to the new mergerd galazies overall brightness as well.

__________________
There is no problem that cannot be solved by a suitable application of high explosives - US Army Demolitions School

I just saw Hayley's comet, she waved, Said "why you always running in place? Even the man in the moon disappeared, Somewhere in the stratosphere" - Shinedown

http://worldsofothersuns.home.comcast.net/

Taking a quess here, but, if galaxy mergers are a factor we would have two sets of data, merged and non merged galaxies and one set wouldn't obey the Tully-Fisher relationship. Since it appears they follow this trend then my quess is that it's not the cause.

__________________
MrObvious

Also remember that, relatively speaking, the black holes at the center of galaxies are a relatively small fraction of the mass of the galaxy. A few million solar masses may seem huge, but out of a total mass of a trillion solar masses or so, it just doesn't represent a large fraction of the mass of the galaxy. So, maybe because of the black hole there are a million fewer stars in a typical galaxy than there would be otherwise. Why would we expect that to reduce the overall galactic luminosity by more than a tiny fraction?

I wonder if the Tully-Fisher relationship applies to elliptical galaxies, which might be result of mergers. So perhaps ellipticals might be the other set not obeying Tully-Fisher relationship.

__________________
"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums]

Good point. Over time though, all of the galactic matter should feed into the center. In an evolving universe, this means galaxies that are mature in the Deep Hubble fields should be fading today, as more and more of the mass is gobbbled up. Therefore there should be an evolution in the Tully-Fisher relationship - Massive galaxies today should be brighter than massive galaxies observed ions ago. Is this observed?

Galaxie mergers could effect the equation as well, but here again, the resulting core mass (in a true merger - there is evidence galaxies may pass right through each other somewhat unscathed), should on average over time created a diminishing luminosity function.

To say that the universe is not old enough to observe this effect is a very iffy arguement: We should expect a Gaussian distribution in the initial energys supplied when galaxies formed, so a 'red tail' of very high density, low luminosity galaxies should exist. Do they? Where are they?

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

The Universe is not old enough to observe free protons decay.

__________________
papageno


"Why waste time learning, when ignorance is instantaneous?" - Hobbes (Calvin and Hobbes)

"It's all about context!" - Vince Noir (The Mighty Boosh)

"I've never heard of such a brutal and shocking injustice that I cared so little about!" - Zapp Brannigan (Futurama)

"...because the logic of the lines traced from reality is as poor of aesthetic value as it is strict in consistency. " - Paolo Bozzi (Naive Physics - free translation)

An idea from a previous thread where somebody asked what would happen if our sun was suddenly converted into a same mass BH. The consensus was that the planets would continue on there merry way without any disturbance of their orbits since our primary’s mass would not have changed. Makes me wonder if once the black hole has gobbled up all the local matter (even in a mature galaxy) it’s consumption would drastically decrease unless an outside force radically altered the galaxy’s shape, stellar orbits or what have you to once again direct matter towards the black hole.

__________________
Photons have mass? I didn't even know they were Catholic.

Exactly. After some period of time a massive black whole will already have gobbled up all the other matter close enough to be eaten or drawn into it's "danger zone" from which another body can not escape being eventually devoured. After a while, there just won't be anything left in reach.

Here is a totally different idea, maybe out there with "wormholes" and "time travel", but I have cause to think it is this:
--quote mine/ Ivan

I leave this here only for the record. Solar masses collapsing or falling into black holes have nothing to do with their size or growth. Rather, the extremely high spin around black holes converts these solar masses to lightspeed energy instead, which further feeds the black hole. The spin off dividend is ionized hydrogen proto-atoms spun out the galactic axis, which will seed the galactic disk with future hydrogen molecules, which will gravitationally collapse into hot radiant stars, which will feed radiant energy into the black hole, and so on. It's a continuous system.

Check back in a few decades, when cosmology goes the next step. They'll call it the "Alexander effect".

Cheers.

__________________
Caveat Lector. Experimentum summus judex...

Over time, maybe, but over a lot of time. I'll repeat, the current estimate I've seen for the black hole mass for the Milky Way is about 0.0002% of the total galactic mass, and that's at the present. If the black hole were to continue to grow at the same rate, then in another 13 billion years or so, it might account for 0.0004% of the galactic mass, and we're not going to be able to notice a significant difference in the luminosity. If we wait 60 trillion years or so (5,000 times the age of the current universe!), the fraction would finally start to approach 1%, and maybe then we might notice a trend, but it would still be subtle. A difference in brightness this small is completely swamped by the random and systematic variations in the luminosity to mass ratio of galaxies; there's just no way it would be observable.

I disagree. The tails on a Gaussian distribution fall off pretty quickly. But even if the occasional central black hole is ten times larger than the Milky Way's, relative to its own galaxy's mass, now we're talking about accounting for 0.002% of the galactic mass. How could we possibly notice a trend that slight among all the other effects that can cause a galaxy's overall brightness to vary? Especially since a measurement of the absolute luminosity of a galaxy also depends on a distance measurement.

Wouldn't this be observable? Younger galaxies would have stronger X-Ray emissions.

__________________
Do try not to take me too seriously.

Black Hole do not exists. There are very massive objects with conditions near Black Hole. Do you know that time close to Black Hole slows down ?

It is very difficult to create a very massive star. Such a star radiate tremendous energy and kick gas and dust out. Heavy stars are created when similar stars mergers together only. It is very rare in our such empty Universe. It was possible at the beginning when the Universe was very dense.

Every big star evaporate its energy and mass and new born galaxies are created around small “Black Holes”. If something comes from accretion disc into central very heavy star it is accelerated and became high energetic and transformed into particle-antiparticle and ejected in jets. This jets carry out the star’s energy and mass.

Elliptical galaxies tend to lie on the "fundamental plane", which is defined in a 3D space formed between effective radius, effective surface brightness (or luminosity) and velocity dispersion. You can get something similar to the Tully-Fisher relationship by projecting the fundamental plane down on to the luminosity/velocity dispersion plane; this is analogous to the Tully-Fisher law and is known as the Faber-Jackson law. The scatter in the FJ law is rather greater than in the TF law, since the FJ law is only a projection of the much tighter fundamental plane relationship.

Tully-Fisher relationship indicate a mass of the galaxy but we can’t see a star in a center.
It seems that if the Universe was denser (Big Bang or Local Big Bang in Rotating Universe) earlier, there were a heavy rotating clouds of gas ejected. We see them as Quasars with accretion disc. They transform their energy in ejected matter and created new stars circled around heavy center.

I do not think , the early quasar’s center was a Black Hole. It was a gaseous rotating nebula with parameters near Black Hole.
Many particles and energy radiate out and some clouds of gas create at least the stars (some of them neutron stars) circle around joint center. It is not possible to create a real Black Hole like M/R = c^2/G. How do you think ?

If there are 2 stars with parameters M/R close c^2/G each of them and they approach very close and rotate.
According to relativistic time delation of Lorentz T=T(o)/(1-v^2/c^2)^1/2 will they at least stay motionless ?
They have very big mass but according to Tully-Fisher very faint and small. http://www.space.com/scienceastronom...ole_birth.html

I think Grey's answer is pretty good...neglecting, of course, the unresolved inflation issue.

Try this one.

__________________
jwj

It's a big universe out there...is it really unwinding, really burning out?

I'm not quite sure what inflation has to do with this thread at all, but I'll take a look at your cosmic ray question in a bit.