Black Hole kick observed

[publius]

Forgive me if this has been ToSeek'ed and I didn't see it, but they've observed a supermassive black hole, the result of a merger, being kicked out of the host galaxy by the massive gravitational radiation recoil kick predicted by GR simulations of merger events.

http://www.space.com/scienceastronom...superkick.html

We've discussed this here a few times and I knew they hadn't yet observed it, but were looking. Well, they've found one now.

This should be seen as more good, but indirect, evidence for gravitational radiation, on a par with the binary pulsar inspirals.

ETA: the recoil velocity here is *amazing*. The big boy got a kick speed of ~2700 km/s. And that is one heck of a lot of radiation blasting out in the other direction, too.

This would make for a good movie plot. We learn that one of these rogue supermassive black holes is headed right for us!

ETA2: Tony, or any other gravity simulator gurus (those who know the program well enough to quickly set it up), just for fun, run a simulation of a 100 million Sol mass ripping through the solar system at oh, say, 1000 km/s. Let it come in in the plane, and then let it come perpendicular to the ecliptic. I'd just like to see what that would do.

-Richard

[Neverfly]

http://www.bautforum.com/universe-to...servation.html
Fraser beat ya to the punch- but that's to be expected.

[Neverfly]

This would make for a good movie plot. We learn that one of these rogue supermassive black holes is headed right for us!

We can run around in a panic fretting what we will do in a couple hundred thousand years when it arrives and the actors will be encouraged to look worried but relaxed.

[frankuitaalst]

There's no reason to panic ....
Even a black hole can't destroy us ...
If the black hole (1 Mio Suns ) starts at 1000AU above our heads and moves with 1000 km/s towards Sol , it will reach us in less than 2 years .
The animation herunder (Gravity Simulator ) depicts the scene as seen from "above" , during the last days of the approach .
The sun and the black hole appear in the center of the frame .
The inner planets Mercury to Mars are shown as they orbit the sun .
Due to the pull of the black hole Jupiter and Saturn are pulled inwards , later on also the inner planets are pulled towards the attractor .
At the end the BH has a relative speed of more than 50.000 km/s.
Finally the BH collides with Sol , Sol vanishes ...
Remarkably all the planets survive , but orphinized they are injected into space , drifting away from the black hole.
No 2012 scenario

[m1omg]

There's no reason to panic ....
Even a black hole can't destroy us ...
If the black hole (1 Mio Suns ) starts at 1000AU above our heads and moves with 1000 km/s towards Sol , it will reach us in less than 2 years .
The animation herunder (Gravity Simulator ) depicts the scene as seen from "above" , during the last days of the approach .
The sun and the black hole appear in the center of the frame .
The inner planets Mercury to Mars are shown as they orbit the sun .
Due to the pull of the black hole Jupiter and Saturn are pulled inwards , later on also the inner planets are pulled towards the attractor .
At the end the BH has a relative speed of more than 50.000 km/s.
Finally the BH collides with Sol , Sol vanishes ...
Remarkably all the planets survive , but orphinized they are injected into space , drifting away from the black hole.
No 2012 scenario

I guess Gravity simulator do not simulate the destroying of the planets from gigantic enormous tidal forces?

And you call the destruction of the Sun with planets flung outwards (I guess in reality they would be ripped apart by the tidal forces) "not 2012 scenario"?!

This Gravity simulator CANNOT simulate tidal forces or the gigantic clouds of extremely hot gas that would be heated to hundreds of million degress by the BH accreting and this applet http://xaonon.dyndns.org/hawking/ gives the radius of the event horizon as about 300 million km, so the BH would engulf all the inner Solar system!

Use your own intelligence, not only some automated programmes please next time.

Even if the planets were composed of pure indestructable unoptanium the hot gas from the remains of the Sun and then the cold of interstellar space would kill all life.

It would be trillion times worse than any "2012" woo woo.
And it would not just destroy our Solar system, I guess that entire galaxy would be ripped apart and degenerate into a cloud of rogue planetless stars and gas.
Of course any star system to that it would came would suffer the same horrifying fate as ours - half being ripped apart, half being engulfed.

[frankuitaalst]

I guess Gravity simulator do not simulate the destroying of the planets from gigantic enormous tidal forces?

And you call the destruction of the Sun with planets flung outwards (I guess in reality they would be ripped apart by the tidal forces) "not 2012 scenario"?!

This Gravity simulator CANNOT simulate tidal forces or the gigantic clouds of extremely hot gas that would be heated to hundreds of million degress by the BH accreting and this applet http://xaonon.dyndns.org/hawking/ gives the radius of the event horizon as about 300 million km, so the BH would engulf all the inner Solar system!

Use your own intelligence, not only some automated programmes please next time.

Even if the planets were composed of pure indestructable unoptanium the hot gas from the remains of the Sun and then the cold of interstellar space would kill all life.

It would be trillion times worse than any "2012" woo woo.
And it would not just destroy our Solar system, I guess that entire galaxy would be ripped apart and degenerate into a cloud of rogue planetless stars and gas.
Of course any star system to that it would came would suffer the same horrifying fate as ours - half being ripped apart, half being engulfed.

You're right m1omg.
Gravity Simulator does not calculate the tidal forces of course , nor the radiation experienced by the merging of our poor Sun . But is does indeed account for the gravitational effects and generates non relativistic orbits .
The scenario would indeed be catastrophic , but ...it may not seem as our total solar system would be sucked into the BH as some "2012" guys would suggest .
Therefor the

[m1omg]

You're right m1omg.
Gravity Simulator does not calculate the tidal forces of course , nor the radiation experienced by the merging of our poor Sun . But is does indeed account for the gravitational effects and generates non relativistic orbits .
The scenario would indeed be catastrophic , but ...it may not seem as our total solar system would be sucked into the BH as some "2012" guys would suggest .
Therefor the

Sorry,

I've never heard the version of 2012 pseudoscience about all the solar system sucked into a black hole, just that ordinary crackpot stuff about the Mayan calendar and brown dwarfs coming from nowhere heating Earth and coming to flip poles and destroy orbits .

I know it calculates gravity accurately on Newtonian model, but wouldn't black hole create some interesting effects because the gravity near the horizon behaves non-Newtonianly, with Einstein's relativity effects being obvious?

And could you do the model again, with the real BH (event horizon of it actually) size please?
And, also, at what velocities are the planets ejected (if they survived) and how fast it would happen?

[frankuitaalst]

Sorry,

I've never heard the version of 2012 pseudoscience about all the solar system sucked into a black hole, just that ordinary crackpot stuff about the Mayan calendar and brown dwarfs coming from nowhere heating Earth and coming to flip poles and destroy orbits .

I know it calculates gravity accurately on Newtonian model, but wouldn't black hole create some interesting effects because the gravity near the horizon behaves non-Newtonianly, behaving as in Einstein's model of gravity?

Indeed BH give very weird gravitational fields . Please forgive me not being familiar with this highly advanced theory . I wonder who of us is capable to run such simulations ?
Orbits around black holes fi. seem not to be "closed" as they do in the Newtonian model . Weird .
Considering the black hole as a point mass , also considering Newtonian behaviour , neglecting tidal forces and radiation ,...in one word ...applying classical dynamics on the solar system the pass of a BH may look as herunder .
Ok : just for fun : starting conditions are : BH originally at 1000AU at the right , vertical offset of 10AU and initial velocity of 1000 km/s . Mass : 10^6 Solar Mass. Animation runs for ca. 10 years.
The BH reaches the solar system ( in fact the solar system reaches the BH ..) after ca. 2 years. Watch the mess the BH creates .
Due to the initial offset the BH misses the sun .
So in this scenario the sun is conserved , but looses most of it's planets .
No planet merges with the BH .
Due to the hughe accelerations Earth is no longer capable to keep its moon .
The moon is separated from Earth .
This simulation is of course only one of the millions of other posibilities , which hopefully will never occur .

[trinitree88]

Now, now, everybody is missing the real point....there's an opportunity here. There are million upon millions of vertically challenged people who would like nothing better than to be a foot taller with no dieting, no anabolic steroids, no running hundreds of miles....etc.
All they need to do is sign up for our first annual pilgrimmage to the black hole. We sell tickets to Virgin Atlantic Black Hole Day...and when it's due to pass through the solar system we guarantee that when their spaceship gets within the Roche lobe....they'll get their free stretching. (It's also good for dislocations, humpback, lazy eye, crooked fingernails, and souffles that fell when Junior opened the oven door too soon....)

pete

[NEOWatcher]

Now, now, everybody is missing the real point...

I see a scam... Wouldn't it have been booked on Virgin Galactic?

[publius]

Don't worry. Doing the actual strong near field solutions of the solar system near that monster would be something that requires the supercomputers and talents of the numerical relativity group at the Max Planck institute.

Oh, and I forgot. The horizon of 100million Sol mass is 300 million km. That's around 2AU! So anything that comes with 2AU is certainly gone. However, the strong field where things are very non-Newtonian extends somewhat beyond that. At a minimum, I'd plug in 3 times that, or a whopping 6AU as the radial "size" of this thing, and let anything that comes within that just collide and merge. That will just be a placeholder for we don't know what happens. It could be pulled in or thrown out, not to mention what the tidal forces that close in would do.

A 100million Sol BH is so big it's ridiculous. Get it too close to the solar system and it just overwhelms everything. For more "fun", we might imagine a Milky Way mass BH of only 1 million Sols. The EH there would be 3 million km, and let the "size" there be 10 or 15 million km. It might be interesting to let that shoot through. The resulting of trajectory of anything that didn't "collide" there would probably be pretty close.

Or the "glancing" runs, where it just shoots close by might be even more interesting.

ETA: And another thing -- the low velocity limit: Things begin to get non-NEwtonian, even in the weak field zone, when v/c becomes appreciable. 50,000km/s is ~17% c, and deviations would start becomming apparent there. I'd let 10% c be the limit there, and flag anything that got too much faster than that.

-Richard

[publius]

Use your own intelligence, not only some automated programmes please next time.

I don't think anyone here, certainly not me, thought this would be an accurate model. It was just a Newtonian starting point to see what havoc such a monster ripping through would do.

And the tidal forces of "ginormous" black holes at a given R/r fraction, are actually less than with smaller black holes. It turns out that for a radial free faller, the radial tidal force is exactly the Newtonian result of 2GM/r^3. And that holds all the way in, even at the horizon (which event occurs only in the proper time of the free faller, not external coordinates). Now, for r = R, the horizon, that's

2GM/R^3.

But recognizing that R = 2GM/c^2, you see the tidal force decreases inversely as square of the mass.

Now, orbiting tides get some rather complex corrections and are indeed larger, especially for very fast orbits close in, but that is beyond my back of the envelope capabilities.

-Richard

[William]

I think this is the paper which is the base for the news release. The black hole “kick” is I believe a hypothesis, as to why two massive objects would not become gravitational bound to each other. There is no direct observational evidence to confirm one black hole can kick another. i.e. There could be another explanation as to why a massive compact object has the ability to kick another.

The paper notes that one BH’s ability to kick another is, within the logic of the hypothesis, maximized if both BH are equally sized and have high rotational speeds and anti-aligned spins.

The whole parameter space of BH recoil velocities is still being explored (e.g., Baker et al. 2006, 2007, Campanelli et al. 2007a,b, Choi et al. 2007, GonzŽalez et al. 2007a,b, Herrmann et al. 2007a,b, Pollney et al. 2007, Schnittman et al. 2008, and references therein; see Pretorius 2007 for a review). Several recent calculations focused on (almost) equal mass BHs with specific spin configurations such that kick velocities are maximized. The line-of-sight velocity we measure is comparable to the recoil velocities predicted by the runs of GonzŽales et al. (2007b; vkick ≈ 2500−2650 kms−1) and by Dain et al. (2008; 3300 kms−1). The scaling formulae of Campanelli et al. (2007a) and of Baker et al. (2008) predict maximal recoil velocities of ∼3800 kms−1. In order to reach a high kick velocity, the pre-merger BHs of SDSSJ0927+2943 must have been rapidly spinning and of nearly equal mass; i.e. the galaxy hosting SDSSJ0927+2943 must have undergone a major merger.

http://lanl.arxiv.org/abs/0804.4585v1

A recoiling supermassive black hole in the Quasar SDSSJ092712.65+294344.0?
S. Komossa, H. Zhou, H. Lu

[parejkoj]

You know, William, for all the quoting of papers you do around here, you really don't seem to actually read them. There are at least a dozen references in that article to papers describing analytic and numerical simulations of black hole mergers where the resultant merged black hole gets a very large kick. Note that this is not a situation where one black hole sends another flying away, but where the pair of black holes merge to form a larger one, and the gravitational radiation from the merger causes the new black hole to go shooting off at high velocity. Similar kicks are expected in stellar-collapse black holes and neutron stars, as predicted by Bekenstein (1973).

Just a few of those papers: Baker et al. (2007), Baker et al. (2006), Blanchet, Qusailah & Will (2005), Bogdanović et al. (2007), Campanelli et al. (2007).

This paper represents the first possible observation of such a system. It isn't convincing yet (there are many examples of line-of-sight superpositions that would look very similar), but it's the closest one yet. Bonning, Shields & Salivander (2007) also looked for such systems in the SDSS, but found none.

So William: what are you complaining about?

[publius]

First, a clarification to make things perfectly clear. This is not one black hole kicking another. This is two black holes merging, and during the merger, emitting a massive burst of directional gravitational radiation which kicks the merged black hole in the opposite direction. This is massive, spectacular gravitational radiation recoil according to the predictions (numerical simulations, not exact solutions which no one has, nor even thinks exist analytically so complex are the equations).

So, various complex numerical GR simulations come up with this pretty amazing, and very non-Newtonian result that two merging BHs, of certain properties (mass and angular momentum, both spin and orbital) will radiate as they merge and produce this large recoil kick.

THat's a gee-whiz type of thing and so they go to looking for evidence of it, and lo and behold, they find something consistent with this. Again, this is up there with the binary pulsar inspirals, observational evidence consistent with some of the wild and crazy strong field GR behavior.

And William, looking over your previous posts, I see you may be a Mitra/ECO/MECO proponent. I'm a little bit familiar with that, and find it fascinating. For any lurkers not familiar, Mitra (and a few others, some converts as it were), argue that the "cold collapse" model of black hole formation is flawed -- the simplifying assumptions are wrong and don't apply to a real collapse. An event horizon and singularity do not form in the proper time of the collapsing object, and it converts all it's mass to radiation and radiates away all its mass-energy eventually (just like Hawking radiation, really -- although bu vastly different mechanisms). The time scale is ridiculous, orders upon orders of magnitude times the age of the universe. No one that I know of has yet found the flaw (if any) in Mitra's math and arguments.

Mitra is not some "anti-GR" type. No, he uses GR and says that the cold dust collapse to singularity solution is flawed.

But whether these are MECOs or "real" black holes with event horizons makes no diffference. If Mitra is correct, ECO/MECOs, to external observers, are so close to a black hole, huge mass in very small space that they behave just about the same. The only difference would be a MECO could have the slightest amount of "hair", a bit of peach fuzz if you like. The "surface" would be so time dilated (rather than z = infinity at the horizon, z = really, really big, but finite number ) and take so long for anything to escape that it would make no difference.

And thus it's my hunch that two merging MECOs would do the same spiral and radiation recoil kick as two real black holes. MECOs vs black holes would be a real theoretical difference, singularity and horizon vs none, but again, externally, they would be very close.

This is thus not a question of whether an event horizon is really there, only the "wild and crazy" GR behavior of two massive, super strong field objects merging and radiating.

-Richard

[William]

In reply to parejkoj's comment:

You know, William, for all the quoting of papers you do around here, you really don't seem to actually read them. There are at least a dozen references in that article to papers describing analytic and numerical simulations of black hole mergers where the resultant merged black hole gets a very large kick.

I guess I try to solve the problem, as opposed to quote papers. I can think about and discuss the observations, in terms of more than one hypothesis.

As noted, observational evidence supports the hypothesis that the massive compact object has a strong intrinsic magnetic field, that the massive compact object is not a hairless BH.

But if you wish, keep the hairless BH hypothesis. Try to use it to explain other observations, say galactic evolution and morphology for example. Lack of evolution of quasar metallicity or quasar density evolution, with redshift. I found the anomalous high temperature of intergalactic gas for galactic clusters to be interesting. (The intergalactic gas should cool and collapse in the centre of the cluster and does not. The cooling mechanism increases when the gas collapses.)

Observationally, a massive compact object was ejected. That is what must be explained and is possibly a hint to the solution. Did you look at the Paradox of Youth observations?

[frankuitaalst]

Don't worry. Doing the actual strong near field solutions of the solar system near that monster would be something that requires the supercomputers and talents of the numerical relativity group at the Max Planck institute.

Oh, and I forgot. The horizon of 100million Sol mass is 300 million km. That's around 2AU! So anything that comes with 2AU is certainly gone. However, the strong field where things are very non-Newtonian extends somewhat beyond that. At a minimum, I'd plug in 3 times that, or a whopping 6AU as the radial "size" of this thing, and let anything that comes within that just collide and merge. That will just be a placeholder for we don't know what happens. It could be pulled in or thrown out, not to mention what the tidal forces that close in would do.

A 100million Sol BH is so big it's ridiculous. Get it too close to the solar system and it just overwhelms everything. For more "fun", we might imagine a Milky Way mass BH of only 1 million Sols. The EH there would be 3 million km, and let the "size" there be 10 or 15 million km. It might be interesting to let that shoot through. The resulting of trajectory of anything that didn't "collide" there would probably be pretty close.

Or the "glancing" runs, where it just shoots close by might be even more interesting.

ETA: And another thing -- the low velocity limit: Things begin to get non-NEwtonian, even in the weak field zone, when v/c becomes appreciable. 50,000km/s is ~17% c, and deviations would start becomming apparent there. I'd let 10% c be the limit there, and flag anything that got too much faster than that.

-Richard

Another try with the same "inconveniences" of the GravSimulator not being able to link to the MaxPlanck institute
Starting : BH at 1000 AU above our heads , 1 Mio Solar Mass , 1000 km/s relative speed , EHorizon : 3Mio km , direction : right heading towards Sol .
It takes only 2 years for the BH to reach us. For simplicity the BH was given a diameter of 3 Mio km , being the event horizon .
The animation shows the final days before and after the approach .
The BH arrives from the bottom in this view .
Outer planets Jupiter/Saturn...Pluto loose their bound to sol , while Sol and the inner planets move towards BH .
As a result Sol , Mercury , Venus , Earth are "absorbed" .
The outer planets are capable to escape and seem to fly away in formation away from the BH .
The situation may be less dramatic if the BH just "grazes" by . In the above case we really have a front collision.

[m1omg]

Another try with the same "inconveniences" of the GravSimulator not being able to link to the MaxPlanck institute
Starting : BH at 1000 AU above our heads , 1 Mio Solar Mass , 1000 km/s relative speed , EHorizon : 3Mio km , direction : right heading towards Sol .
It takes only 2 years for the BH to reach us. For simplicity the BH was given a diameter of 3 Mio km , being the event horizon .
The animation shows the final days before and after the approach .
The BH arrives from the bottom in this view .
Outer planets Jupiter/Saturn...Pluto loose their bound to sol , while Sol and the inner planets move towards BH .
As a result Sol , Mercury , Venus , Earth are "absorbed" .
The outer planets are capable to escape and seem to fly away in formation away from the BH .
The situation may be less dramatic if the BH just "grazes" by . In the above case we really have a front collision.

Could you do the simulation with the speed of the BH 2700 km/s and mass of
100 million Suns, please?And I would also interested; at what speeds the planets would escape (these that aren't engulfed)?
And would you please post a link with these Gravity Simulator files here?It don't look too good in lo-res jerky gif animation.
Make it's diameter 1.975198 AU and let it pass the Solar system by 100 AU from the Sun.

[William]

In reply to publius' comment:

So, various complex numerical GR simulations come up with this pretty amazing, and very non-Newtonian result that two merging BHs, of certain properties (mass and angular momentum, both spin and orbital) will radiate as they merge and produce this large recoil kick

I think the authors of the below linked paper that discusses the observation as opposed to the simulation, believe their data supports the conclusion, that one massive compact object has been ejected from its host galaxy. The kick is a kick that ejects the BH. The quasars in questions are moving apart. The first paper parejkoj linked to in response to my comment, also notes the kick that occurs during a merger, can result in BH host galaxy separation. parejkoj's paper also notes the kick result can be determined within 10% using Newtonian physics.

If many BHs were removed from their hosts in the early history of the universe, this would have profound consequences for galaxy assembly and BH growth in the early universe, and would give rise to a population of interstellar and intergalactic BHs (e.g., Madau et al. 2004, Merritt et al. 2004, Madau & Quataert 2004, Haiman 2004, Yoo & Miralda-EscudŽe 2004, Volonteri & Perna 2005, Volonteri & Rees 2006, Libeskind et al. 2006).

http://lanl.arxiv.org/abs/0804.4585v1

A recoiling supermassive black hole in the Quasar SDSSJ092712.65+294344.0?
S. Komossa, H. Zhou, H. Lu

In reply to publius' comment:

This is thus not a question of whether an event horizon is really there, only the "wild and crazy" GR behavior of two massive, super strong field objects merging and radiating.

I guess I agree. i.e. The observations do not prove or disprove an event horizon.

What do the observations prove? Same question to parejkoj.

[parejkoj]

I guess I try to solve the problem, as opposed to quote papers. I can think about and discuss the observations, in terms of more than one hypothesis.

Honestly, William? All I ever see from you is a lot of misquoting of papers plus vague statements about how the standard model can't explain something (which often has one or more possible explanations in the paper you quoted!). So, why don't you "try to solve the problem" and tell us (in a separate thread, please) how the MECO hypothesis would actually predict different observables from the standard GR black hole? But please, don't start by misquoting a bunch of papers and hinting that the standard theory can't explain things that it can actually explain: I've had enough of that.

But if you wish, keep the hairless BH hypothesis. Try to use it to explain other observations, say galactic evolution and morphology for example. Lack of evolution of quasar metallicity or quasar density evolution, with redshift. I found the anomalous high temperature of intergalactic gas for galactic clusters to be interesting. (The intergalactic gas should cool and collapse in the centre of the cluster and does not. The cooling mechanism increases when the gas collapses.)

I have already tried to explain most of those observations to you using the standard theory, in various other threads. You've given me no reason to think that MECO can do a better job, or even that it would be quantitatively different for any of those observations.

Observationally, a massive compact object was ejected. That is what must be explained and is possibly a hint to the solution. Did you look at the Paradox of Youth observations?

I've known about the "paradox of youth" for some time, but I also know that there are a few competing hypotheses for how those young stars got there (here's a hint: they're described in the papers you keep quoting). None of them would be any different under the MECO scenario.

If many BHs were removed from their hosts in the early history of the universe, this would have profound consequences for galaxy assembly and BH growth in the early universe, and would give rise to a population of interstellar and intergalactic BHs (e.g., Madau et al. 2004, Merritt et al. 2004, Madau & Quataert 2004, Haiman 2004, Yoo & Miralda-EscudŽe 2004, Volonteri & Perna 2005, Volonteri & Rees 2006, Libeskind et al. 2006).

What does that have to do with anything we were just talking about? And what does it have to do with MECO?

I guess I agree. i.e. The observations do not prove or disprove an event horizon.

You mean besides the observations previously listed by Tim Thompson? Or do those somehow not count?

What do the observations prove? Same question to parejkoj.

What do what observations prove? I'm still confused as to what your complaint is.

Speaking about the paper linked in the OP, this is by no means conclusive, but it the best possibility yet for a kicked supermassive black hole. VLT, Keck or Hubble observations at very high resolution are needed to distinguish whether this is more than just a superposition of two AGN.

[frankuitaalst]

Could you do the simulation with the speed of the BH 2700 km/s and mass of
100 million Suns, please?And I would also interested; at what speeds the planets would escape (these that aren't engulfed)?
And would you please post a link with these Gravity Simulator files here?It don't look too good in lo-res jerky gif animation.
Make it's diameter 1.975198 AU and let it pass the Solar system by 100 AU from the Sun.

That's really a monster ! As a manner of speaking having one thousand of the galaxys mass and an event horizon equal to Earths orbit around Sol !Without the last sentence I would have guessed the total solar system would have been deleted .
I'll start at 1000AU above the ecliptic .
I'll give it a try and post the results in the GravitySimulator forum . This allows bigger files...

[frankuitaalst]

M1omg ...
I think we have a "2012" scenario with your setup
See the result of the simulation you proposed herunder :
http://www.orbitsimulator.com/cgi-bi...1209843228/1#1
All planets seem to disappear in the event horizon .
I think the BH monster is really too big ...
But your initial settings for velocity may be somewhat "tricky" . At closestencounter the program indicates sun is moving at "c" ....
The picture herunder shows a part of the simulation at the point where Pluto disappears in the event horizon .

[William]

In reply to parejkoj's comment:

Originally Posted by William quoting Komossa, Zhou, Lu (2008)
If many BHs were removed from their hosts in the early history of the universe, this would have profound consequences for galaxy assembly and BH growth in the early universe, and would give rise to a population of interstellar and intergalactic BHs (e.g., Madau et al. 2004, Merritt et al. 2004, Madau & Quataert 2004, Haiman 2004, Yoo & Miralda-EscudŽe 2004, Volonteri & Perna 2005, Volonteri & Rees 2006, Libeskind et al. 2006).

What does that have to do with anything we were just talking about? And what does it have to do with MECO?

The observation was that the BH has ejected from its host galaxy. It did not receive a kick and then started to merge with the other BH. So are we in agreement about the observation?

"And what does that have to do with a MECO?" Good question. Let's see if galaxies with a MECO are different that galaxies without a MECO. I am researching galaxy morphology and evolution. Interesting subject. Need more time, to answer or at least to sensibly discuss that question.

[parejkoj]

The observation was that the BH has ejected from its host galaxy. It did not receive a kick and then started to merge with the other BH. So are we in agreement about the observation?

Huh? I don't understand your claim at all.

The paper claims to have found a supermassive black hole with a very large velocity relative to its (former) host galaxy. The most likely explanation for this is the "kick" caused when two spinning black holes merge (see all the papers I listed above). I still don't understand your complaint, nor the relevance of the quote you listed to any of this conversation.

"And what does that have to do with a MECO?" Good question. Let's see if galaxies with a MECO are different that galaxies without a MECO. I am researching galaxy morphology and evolution. Interesting subject. Need more time, to answer or at least to sensibly discuss that question.

I'm still waiting for you to start an ATM thread about your MECO ideas, which are quite far from the hypothesis put forward by Schild et al.

And you appear to be ignoring (again) the rest of my response to your "complaints."

To frankuitaalst:
Don't get too worked up over this! Remember, this situation can only happen if two rapidly spinning, supermassive black holes merge perpendicular to their spin axis. That happens only rarely, and there are no candidates in our neighborhood to produce it. Though one might wonder about the merger of M31 and the Milky Way: both have ~million solar mass black holes in their center, but their spin rates (and axes) are unknown.

[m1omg]

M1omg ...
I think we have a "2012" scenario with your setup
See the result of the simulation you proposed herunder :
http://www.orbitsimulator.com/cgi-bi...1209843228/1#1
All planets seem to disappear in the event horizon .
I think the BH monster is really too big ...
But your initial settings for velocity may be somewhat "tricky" . At closestencounter the program indicates sun is moving at "c" ....
The picture herunder shows a part of the simulation at the point where Pluto disappears in the event horizon .

Well, Newton allowed speeds greater than c so it's no surprise.
Under Einstein's relativity it would probably do the same, just that instead of greater than c velocieties you will get chaotic trajectories right before the objects in our Solar system are eaten by the BH.

[frankuitaalst]

Huh? I don't understand your claim at all.

To frankuitaalst:
Don't get too worked up over this! Remember, this situation can only happen if two rapidly spinning, supermassive black holes merge perpendicular to their spin axis. That happens only rarely, and there are no candidates in our neighborhood to produce it. Though one might wonder about the merger of M31 and the Milky Way: both have ~million solar mass black holes in their center, but their spin rates (and axes) are unknown.

Thanks for the reassurement ...Parejkoj .
That's really good news .
As a matter of fact I made the simulation above just for fun or exercise...These extreme gravitional fields are really beyond our comprehension ...or do they ?

[frankuitaalst]

Well, Newton allowed speeds greater than c so it's no surprise.
Under Einstein's relativity it would probably do the same, just that instead of greater than c velocieties you will get chaotic trajectories right before the objects in our Solar system are eaten by the BH.

I guess you're right . Under relativistic assumptions the outcome may be the same . Maybe the whole thing would evolve somewhat slower . You've put the initial settings really ...extraordinary .

[publius]

M1omg ...
I At closestencounter the program indicates sun is moving at "c" ....

Well, that could happen with Newton and 100 million solar masses, but it indicates things went non-Newtonian well before that. As I mentioned above, for rough purposes, I'd use a velocity cutoff of 0.1c and a distance cutoff of at least 3R (R = event horizon). For the 100million Sol mass,
3R ~ 6AU is so huge relative to the solar system that it's just too much.

In the strong field regime, things do get very weird relative to Newtonian behavior. While the GR N-body is a humdinger, I assure, exact solutions for simple test particles in Schwarzschild exist and are relatively straightfoward. The orbital trajectories (ie with tangential velocity) get rather complex, but the radial free fall trajectories are fairly simple.

Dropped from infinity on a radial free fall trajectory, a test particle reaches a maximum coordinate speed of "only" around 30% c at r = 3R, then the extreme time dilation begins to slow it down (in the far away Schwarzschild coordinates) for the "freeze" at the horizon. Now, that's the coordinate speed. The local speed for a stationary observer at 3R would be
c/sqrt(3) ~ 57% c.

You would do a "GR N-body" like this in the equivalent of far away Schwarzschild like coordinates (asympotically flat), and so if radial free fall coordinate speed doesn't get over 30% c, you can see why I'd use 10%c as the cut off for a simple Newtonian simulation.

THe orbital/tangential components are different. At some point (what r I can't remember) circular orbital speed *exceeds* radial free fall speed. That speed becomes exactly 'c' (locally, mind you) at 1.5R, the so-called photon sphere.

And, while all that's well and good, a real black hole would not be a simple Schwarzschild one, but most likely a Kerr rotating hole with lots of frame dragging, which gets very, very complex indeed.

We definitely need the numerical GR people there.

-Richard