Astronomers spot signs of supermassive black hole mergers

Astronomers spot signs of supermassive black hole mergers
Jets from double black holes change direction continuously. The effect can explain features in this 5 GHz radio map of 3C 334 and many powerful radio sources in the sky. The jet emanates from the nucleus of a galaxy (its stars are not visible at radio frequencies) about 10 billion light years from our own. The image spans five million light years from left to right. The peculiar structure of the jets signifies a periodic change of the direction of the jet (precession), an effect that is predicted for jets from black hole pairs. The inset diagram schematically illustrates the physical processes in the black hole pair. Jets may form in gas discs around black holes. The direction of the jets is tied to the spin of the black hole. The spin axis is shown as a red arrow. The latter changes direction periodically due to the presence of the second black hole. Credit: M. Krause / University of Hertfordshire

New research, published today in the journal Monthly Notices of the Royal Astronomical Society, has found evidence for a large number of double supermassive black holes, likely precursors of gigantic black hole merging events. This confirms the current understanding of cosmological evolution—that galaxies and their associated black holes merge over time, forming bigger and bigger galaxies and black holes.

Astronomers from the University of Hertfordshire, together with an international team of scientists, have looked at radio maps of powerful jet sources and found signs that would usually be present when looking at that are closely orbiting each other.

Before black holes merge they form a binary black hole, where the two black holes orbit around each other. Gravitational wave telescopes have been able to evidence the merging of smaller black holes since 2015, by measuring the strong bursts of gravitational waves that are emitted when binary black holes merge, but current technology cannot be used to demonstrate the presence of supermassive binary black holes.

Supermassive black holes emit powerful jets. When supermassive binary black holes orbit it causes the jet emanating from the nucleus of a galaxy to periodically change its . Astronomers from the University of Hertfordshire studied the direction that these jets are emitted in, and variances in these directions; they compared the direction of the jets with the one of the radio lobes (that store all the particles that ever went through the jet channels) to demonstrate that this method can be used to indicate the presence of supermassive binary black holes.

Dr. Martin Krause, lead author and senior lecturer in Astronomy at the University of Hertfordshire, said: "We have studied the jets in different conditions for a long time with computer simulations. In this first systematic comparison to high-resolution radio maps of the most powerful radio sources, we were astonished to find signatures that were compatible with jet precession in three quarters of the sources."

The fact that the most powerful jets are associated with binary black holes could have important consequences for the formation of stars in galaxies; stars form from cold gas, jets heat this gas and thus suppress the formation of stars. A jet that always heads in the same direction only heats a limited amount of gas in its vicinity. However, jets from change direction continuously. Therefore, they can heat much more gas, suppressing the formation of stars much more efficiently, and thus contributing towards keeping the number of in within the observed limits.


Explore further

When radio galaxies collide, supermassive black holes form tightly bound pairs

More information: Martin G H Krause et al, How frequent are close supermassive binary black holes in powerful jet sources?, Monthly Notices of the Royal Astronomical Society (2018). DOI: 10.1093/mnras/sty2558
Citation: Astronomers spot signs of supermassive black hole mergers (2018, October 23) retrieved 24 April 2019 from https://phys.org/news/2018-10-astronomers-supermassive-black-hole-mergers.html
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Oct 23, 2018
I would be curious to look at the simulation of a supermassive black hole merger in terms of its gravitational wave output. The kinds of GW signatures we have seen so far come from very small events comparatively speaking. I am just wondering if the GW from a truly massive merger could cause stellar disruption in the inner disk of the surrounding galaxy. This is turn could allow past supermassive BH mergers to be detected from long ago.

Just idle speculation while I wait for my compile to finish...

Oct 23, 2018
I would be curious to look at the simulation of a supermassive black hole merger in terms of its gravitational wave output. The kinds of GW signatures we have seen so far come from very small events comparatively speaking. I am just wondering if the GW from a truly massive merger could cause stellar disruption in the inner disk of the surrounding galaxy. This is turn could allow past supermassive BH mergers to be detected from long ago.

Just idle speculation while I wait for my compile to finish...

A binary SMBH merger would not be in the spectrum range of Advanced LIGO http://www.tapir....rum.html
To detect this kind of merger you will have to wait for LISA. https://en.wikipe..._Antenna

Oct 23, 2018

A binary SMBH merger would not be in the spectrum range of Advanced LIGO http://www.tapir....rum.html

That's gonna be one BIG interferometer....:-)

Oct 23, 2018
Now that's interesting. 75% of SMBH at the cores of active galaxies are binary, huh? And that means that mergers are fairly common, too, since that's pretty much the only way you get two SMBHs.

Oct 24, 2018
That was an unexpected - to me - help in solving the star formation problem.

I am just wondering if the GW from a truly massive merger could cause stellar disruption in the inner disk of the surrounding galaxy.


The reason why GW was so long in discovery was that it such a weak effect. On the scale of LIGO the displacement is about the dimension of a nuclei, on the scale of star distances the width of a human hair.

Looking at sound waves of a star like Sun with a diameter of ~ 10^6 km [ https://en.wikipe...wiki/Sun ], the asteroseismic displacement is "up to several-per-cent change in radius" [ file:///C:/Users/torbj/Downloads/ISSsec4.pdf ] so perhaps ~10^4 km. While the GW displacement scaled from LIGO is ~10^6*10^-15 or 10^-9 m, or a factor 10^13 less - give or take my back-of-the-envelope errors.

I would not expect any visible effects.

Oct 24, 2018
Astronomers spot signs of supermassive black hole mergers

The title of the article needs an adjustment;
'Plasma ignoramuses pontificate fanciful on Dancing Leprechauns while actually observing plasmoids, electric currents, and real plasma processes'

Oct 24, 2018
Regarding gravitational waves, via the abstract (https://arxiv.org....04050):

We consider complementary evidence and discuss if any jetted supermassive black hole with some indication of precession could be detected as individual gravitational wave source in the near future. This appears unlikely, with the possible exception of M87.


The PDF notes gravitational waves from M87 might be detectable:

[The best candidates for gravitational wave detections] are generally of the order of 10^−17 except for M87 [...] where h0 could be as high as 10^−15. Pulsar timing with the Square Kilometre Array radio telescope is expected to detect gravitational waves at relevant frequencies down to h0 = 6 × 10−16 (Lazio 2013)

Oct 24, 2018
Astronomers spot signs of supermassive black hole mergers

The title of the article needs an adjustment;
'Plasma ignoramuses pontificate fanciful on Dancing Leprechauns while actually observing plasmoids, electric currents, and real plasma processes'


Only one ignoramus claiming such idiotic crap as plasmoids to explain BHs, and that is you, woo boy. I keep asking - show us the maths behind the observed orbits of the stars around Sgr A* using a non-existent plasmoid. Only an idiot would suggest such a thing.

Oct 24, 2018
cantdrive85 puts the lotion in the basket or else it gets the hose again.

Oct 24, 2018
Oh cant! You still seeing leprechauns flying about? It would be a big assist to you, if you stop stealing the bowl of whiskey left out for the little guys. Sobriety can help to clear up your delusions of intellectual competency.

Oct 24, 2018
I've always said that @cantdrive85 is a fart smeller, I mean a smart feller, sorry.

Oct 24, 2018
Two half a holes make one

As these paired BHs regurgitate their starry snacks ejecting this plasma in their jets
New unknown properties that has emerged out the BHs of no escape
The jets blow and bend in the cross wind
phys.org> Simulations of jets with crosswinds show that the jets may be bent and are found towards the windward side of the lobes
https://academic..../5105759
What is this BH crosswind we hear you cry
You may well ask because these new startling properties are just starting to emerge out these two holes
This is like two ships at sea on the windward starboard
Looks like we underestimated the stamina of these BHs

Not only are they not singularities
They have no event horizon
As plasma is freely ejected
Out their spin-axis jets
Where these jets bend like the bough
That bends in the winds
That these BHs blow
As they are in binary orbit
As these two ships at sea on the windward starboard reveal these new facts

Oct 24, 2018
They have no event horizon
As plasma is freely ejected
Out their spin-axis jets


Wrong. Stick to poetry, forget the science, it is beyond you.

Oct 25, 2018
2.2.2 Dynamical or asymmetric environments

They have no event horizon
As plasma is freely ejected
Out their spin-axis jets

jonesdave> Wrong. Stick to poetry, forget the science, it is beyond you.

JD, did I say any of what I have just written
Or JD, did I simply copy it from what your good self is eternally for ever requesting
Namely https://academic..../5105759
Reputable scientific links
[ Simulations of jets with crosswinds show that the jets may be bent and are found towards the windward side of the lobes (Balsara & Norman 1992)
The 3D simulations of precessing jets with crosswinds of Rodríguez-Martínez et al.]

Be that as it may JD, this reputable link is in all reality a simulation
But this is the internet of links and related links
In a world of virtual reality
As this is the true reality of BHs JD
BHs in all reality
Are simulations in virtual reality
And that my friend is the reality that is a BH

Oct 25, 2018
And that my friend is the reality that is a BH


I don't need an uneducated idiot to tell me what a BH is or isn't, you tosser. The jets are imaged, thicko. They are not material that has gone beyond the EH, by definition, you plank. Stop commenting on subjects that are way beyond your level of understanding. You just come across as an idiot.

Oct 25, 2018
A dynamic process in accretion-disk then out of spin-axis
And that my friend is the reality that is a BH

jonesdave> I don't need an uneducated idiot to tell me what a BH is or isn't, you tosser. The jets are imaged, thicko. They are not material that has gone beyond the EH, by definition, you plank. Stop commenting on subjects that are way beyond your level of understanding. You just come across as an idiot.

BHs release 50% of the mass they take in snacking on stars from the point of least resistance, namely their spin-axis
It is a dynamic process, with matter piling equatorially from their accretion-disk, where inside the BH, the plasma takes the path of least resistance out the two spin-axis, ejecting plasma into the two star forming 25,000Lyr Fermi-clouds above and below the host galaxy!

Oct 25, 2018
A dynamic process
a BH

jonesdave> thicko. idiot

BHs release 50% of the mass from the point of least resistance out their spin-axis
It is a dynamic process, with matter piling equatorially from their accretion-disk, where inside the BH, the plasma takes the path of least resistance out the two spin-axis, ejecting plasma into the two star forming 25,000Lyr Fermi-clouds above and below the host galaxy!

The Myth of non-rotating BHs
As a point of interest, the reason BHs spin and spin rapidly is simple
BHs are ex-pulsars!
As BHs spin at milli-second rates
As surprisingly, so do Neutron stars
As neutron stars are pulsars
As pulsars are neutron stars
As neutron star as pulsar star as one
Are in all reality
When in collapsing conservation of angular momentum
Creating a rapidly rotating star
Of such rotational rapidity
Of such humongous stellar mass
There is only one possible outcome in the vacuous vacuum
There only exists a rapidly rotating BH

Oct 25, 2018
^^^^^^^Like I said, quit commenting on things that are beyond your understanding. You only come across as an idiot.

Oct 25, 2018
Memories in mind
^^^^^^^Like I said, quit commenting on things that are beyond your understanding. You only come across as an idiot.

This is how our minds remember JD, it has become part of your conscience and your instinct JD, as you cannot shake it off, as your comment purport to prove

Oct 25, 2018
This is how our minds remember JD, it has become part of your conscience and your instinct JD, as you cannot shake it off, as your comment purport to prove


Stop talking crap, you loon.


Oct 25, 2018
A rapidly spinning BH

As you prove your doubt in your mind of instinct
You have yet to disprove the spinning BH derivation in collapsing angular momentum

Oct 25, 2018
You have yet to disprove the spinning BH derivation in collapsing angular momentum


WTF are you talking about, you idiot? Why would I want to disprove it? Jesus, you are a f***wit! Go away, you cretin.

Oct 25, 2018
Gravitational wave telescopes

Is it just me or does the term "telescope" seem wildly wrong for these instruments to anyone else?

I would be curious to look at the simulation of a supermassive black hole merger in terms of its gravitational wave output.

From what I understand they should be harder to detect because the merger distance (teh combined Schwarzschild radii) is larger - thus the 'chirp' part (as well as the ringdown) is lower frequency than with the smaller mergers. At least when I google for the LIGO sensitivity the detectable strain drops of noticeably towards lower frequencies.


Oct 25, 2018
In truth BHs are untruths
You have yet to disprove the spinning BH derivation in collapsing angular momentum

jonesdave> WTF are you talking about, you idiot? Why would I want to disprove it? Jesus, you are a f***wit! Go away, you cretin.

That's a first JD, in your flowery language, admitting the reverse of your apparent mantra that in truth I am correct
Even as we tell factual scientific facts concerning BHs
As we tell these truths
In truth JD, there are in the same instant all lies
Because in truth BHs do not exist as scientific factual facts
As truth and lies are untruths of truthful untruthfulness

Oct 25, 2018
could cause stellar disruption in the inner disk of the surrounding galaxy

Well, you can get a feeling for it if you consider the following:

From the first gravitational wave the signal lasted for about 0.2 seconds and the total energy released in the wave was about 3 solar masses. So consider a shell of width 0.2 light seconds (about 60000km thick) that contains this sort of 'mass' (read: gravitational effect) travelling outward at c. Even though 3 solar masses is a lot It should be apparent that this becomes pretty dilute pretty quickly. So I wouldn't expect huge amounts of supernovae or the likes in its wake. Stars are pretty much fluid-dynamics plasma-balls. Such a distortions shouldn't phaze them unless they are *really* close (a couple AU or thereabouts )

A SMBH merger should release more energy, but the signal length should also be longer. How much the one cancels the other in the above view out is a bit of a guessing game without writing a simulation.

Oct 25, 2018
That's a first JD, in your flowery language, admitting the reverse of your apparent mantra that in truth I am correct


I have never said BHs do not rotate, you f***ing lying cretin. Are you a compulsive liar, as well as being mentally deranged? Why don't you p!ss off, you uneducated moron?


Oct 25, 2018
Nobody does it better
That's a first JD, in your flowery language, admitting the reverse of your apparent mantra that in truth I am correct

jonesdave> I have never said BHs do not rotate, you f***ing lying cretin. Are you a compulsive liar, as well as being mentally deranged? Why don't you p!ss off, you uneducated moron?

Perfection at its best JD, no one does it better
Obfuscation at its finest!

Who else JD
Could turn a derivation
Into a lie to use
As a weapon
Of accusatory truths

Oct 25, 2018
Gravitational travelling wave
antialias_physorg> Stars are pretty much fluid-dynamics plasma-balls. Such a distortions shouldn't phase them

Gravity attracting every other particle under gravitational force the star feels no force, its weightless under free fall, the diluted gravitational wave is like a tsunami out at sea, imperceptible.
But if you can do the calculation the results will be interesting antialias_physorg!

Oct 25, 2018
Sailing gravitational waves

These gravity waves are likened to a pulse jet where each oscillation of gravitational wave is micro-second period, as acceleration is weightlessness, oscillating gravity waves are the solution to sailing the galactic vacuum as acceleration and deceleration on destination arrival is no inertial problem, as there are no forces on galactic ships construction under weightless acceleration of gravity waves!

Oct 25, 2018
Goddammit I love the ignore button.

Oct 25, 2018
Who else JD
Could turn a derivation
Into a lie to use
As a weapon
Of accusatory truths


Will you quit lying you bloody psycho? I have never said anything about BHs not rotating. Now STFU you mentally deranged numpty.

Oct 25, 2018
Granville is getting nuttier and nuttier. His brain must be filling up from reading all the articles here and something else has to leak out.

Oct 25, 2018
Mind your CIRCULARITORY system JD
Who else JD
Could turn a derivation
Into a lie to use
As a weapon
Of accusatory truths

jonesdave> Will you quit lying you bloody psycho? I have never said anything about BHs not rotating. Now STFU you mentally deranged numpty.

No one is WINDING you up JD
I'm just taken lessons in Obfuscation from master tactician
As nobody does it better, Obfuscationaly that is JD

Oct 25, 2018
No one is WINDING you up JD
I'm just taken lessons in Obfuscation from master tactician
As nobody does it better, Obfuscationaly that is JD


WTF are you on about, you dense prat? What have I obfuscated about, you lying clown? Why don't you sod off. There is no point in your being here, you loon.


Oct 25, 2018
Squirrel Nutkin
Ojorf> Granville is getting nuttier and nuttier. His brain must be filling up from reading all the articles here and something else has to leak out.

Well you said it, Ojorf, just like a BH of no escape until it leaks out
What's leaking out is sinking back again

Oct 25, 2018
The key turns again
No one is WINDING you up JD
I'm just taken lessons in Obfuscation from master tactician
As nobody does it better, Obfuscationaly that is JD

WTF are you on about, you dense prat? What have I obfuscated about, you lying clown? Why don't you sod off. There is no point in your being here, you loon.

Just one more turn till the next turn
Keep this up, you'll burst your aneurysm JD

Oct 25, 2018
Just one more turn till the next turn
Keep this up, you'll burst your aneurysm JD


Sod off you moron.

Oct 25, 2018
The key turns again
No one is WINDING you up JD
I'm just taken lessons in Obfuscation from master tactician
As nobody does it better, Obfuscationaly that is JD

WTF are you on about, you dense prat? What have I obfuscated about, you lying clown? Why don't you sod off. There is no point in your being here, you loon.

Just one more turn till the next turn
Keep this up, you'll burst your aneurysm JD


Well granDy, he's been on a psycho-babble routine for quite a long stretch here during his retirement career. His increasingly hostile & foul mouthed rhetoric has without a doubt ramped up in recent months which may be indicative of an increasing pressure along those blood supply vessels. I imagine there will come a not too distant day we will come here to stone cold silence from jonesy, I mean you talk about someone with anger management issues, he's the #1 patient here.

Oct 25, 2018
Only one ignoramus claiming such idiotic crap as plasmoids to explain BHs, and that is you, woo boy. I keep asking - show us the maths behind the observed orbits of the stars around Sgr A* using a non-existent plasmoid. Only an idiot would suggest such a thing.

A lone voice of reason in a sea of dark lunacy.

I have explained how these systems should be addressed. You have never explained how these stars even form given the hypothesized tidal forces in said region.

Oct 25, 2018
I have explained how these systems should be addressed.


No you haven't. You have posited an idiotic piece of woo that no scientist would take seriously. And you cannot explain the orbits of the stars.

Oct 25, 2018
The key turns again
No one is WINDING you up JD
I'm just taken lessons in Obfuscation from master tactician
As nobody does it better, Obfuscationaly that is JD

WTF are you on about, you dense prat? What have I obfuscated about, you lying clown? Why don't you sod off. There is no point in your being here, you loon.

Just one more turn till the next turn
Keep this up, you'll burst your aneurysm JD


Well granDy, he's been on a psycho-babble routine for quite a long stretch here during his u talk about someone with anger management issues, he's the #1 patient here.


Hey, sh!tforbrains, figured out how nuclear fusion works yet? Or what a half-life is? Get back in your cage.

Oct 25, 2018
Hey, sh!tforbrains, figured out how nuclear fusion works yet? Or what a half-life is? Get back in your cage.


See what I mean granDy, every rant just builds the pressure a little higher. The more we post granDy, the more jonesy will post in response, and this builds the pressure a tad higher inside the containment vessel each time, so keep it comimg granDy, likewise for me.


Oct 25, 2018
Hey, sh!tforbrains, figured out how nuclear fusion works yet? Or what a half-life is? Get back in your cage.


See what I mean granDy, every rant just builds the pressure a little higher. The more we post granDy, the more jonesy will post in response, and this builds the pressure a tad higher inside the containment vessel each time, so keep it comimg granDy, likewise for me.



Hahahaha! All that you sad, pathetic, scientifically illiterate loons are doing, is laying bare your ignorance for all to see on here every time you post. Carry on, sh!tforbrains.

Oct 25, 2018
Infinite angular velocity in singularity's of BHs

And as JD turn his own screw, each time the screw getting looser than the last, till the proverbial screw comes loose
To JDs specialist subject
Namely holes of the black variety
Of singularities
In collapsing singularity of momentum
Has JD in his aneurysm of pressure
At the altar of singularities
Ever stopped in mid rant
To realise the stupidity of enormity
Angular momentum in collapsing singularity in all reality actually means
Infinite density
Without infinite gravity
By definition an infinitesimal hole of zero gravity
Where singularity of angular moment
Is infinite angular velocity
How stupid can you be JD
Infinite angular velocity
Infinite angular velocity
It does not get more stupid in duplicate JD
How on earth can you have Infinite angular velocity
Because as you say a BH is a singularity JD
As an ex-pulsar in rotation
Your saying
Infinite angular velocity
In BH rotation, JD,

Oct 25, 2018
Apply your logic and reason simply stumps
In clear Queens English

Welcome simply stumps
The truth in singularities
In Infinite angular velocity

Oct 25, 2018
Because as you say a BH is a singularity JD
As an ex-pulsar in rotation
Your saying
Infinite angular velocity
In BH rotation, JD,


WTF are you on about, badger brain? Where did I say this? Quit lying you psycho loon.


Oct 25, 2018
Because as you say a BH is a singularity JD
As an ex-pulsar in rotation
Your saying
Infinite angular velocity
In BH rotation, JD,


WTF are you on about, badger brain? Where did I say this? Quit lying you psycho loon.


......... pressure is building. I wonder how long before..........?

Oct 25, 2018

......... pressure is building. I wonder how long before..........?


......you admit to lying about being a nuclear engineer, and confess to being a scientifically illiterate loon, who is suffering the terminal stages of D-K syndrome? What is a half-life, putty brain? What is nuclear fusion dependent upon? Come on, regale us with more of your idiocy. It is funny! Nuclear engineer! Hnyuk, hnyuk, hnyuk!

Oct 25, 2018

......... pressure is building. I wonder how long before..........?


......you admit to lying about being a nuclear engineer, and confess to being a scientifically illiterate loon, who is suffering the terminal stages of D-K syndrome? What is a half-life, putty brain? What is nuclear fusion dependent upon? Come on, regale us with more of your idiocy. It is funny! Nuclear engineer! Hnyuk, hnyuk, hnyuk!


Wow, you talk about someone who has a personal obsession with somebody else other than themselves, you are a tempest in a teapot that is boiling over.

Oct 25, 2018
Because you said not inside its Event Horizon, JD
Because as you say a BH is a singularity JD
As an ex-pulsar in rotation
Your saying
Infinite angular velocity
In BH rotation, JD,

WTF are you on about, badger brain? Where did I say this? Quit lying you psycho loon.

A BH by definition of its Event Horizon is a Singularity
Nothing on this earth escapes an event horizon
And so by definition, inside an event horizon is a singularity
A BH JD, is defined by its event horizon
Infinite density
Without infinite gravity
Inside an event horizon
Of singularity
Of infinite angular velocity
For a singularity of absoluteness
Your imagination has gone wild
In this infinitesimal singularity JD
Do you actual socialise in the real world JD
Or do you live in a world of holes in their singularities
Of infinite angular velocity
Has twisted you reality
Such that JD
Your screw has finally come loose

Oct 25, 2018

......... pressure is building. I wonder how long before..........?


......you admit to lying about being a nuclear engineer, and confess to being a scientifically illiterate loon, who is suffering the terminal stages of D-K syndrome? What is a half-life, putty brain? What is nuclear fusion dependent upon? Come on, regale us with more of your idiocy. It is funny! Nuclear engineer! Hnyuk, hnyuk, hnyuk!


Wow, you talk about someone who has a personal obsession with somebody else other than themselves, you are a tempest in a teapot that is boiling over.


And you are a lying, Dunning-Kruger affected, scientifically illiterate loon. As proven. Yes? Lol.

Oct 25, 2018
A BH by definition of its Event Horizon is a Singularity


Wrong, moron. Stick to sh!t poetry. Science is not your thing, eh?

Oct 25, 2018
JDs infamous BH infinite angular velocity

At last JD, it is sinking into that thick skull
The stupidity of infinite angular velocity

We have become accustomed to singularities
And infinite density
But the line begins at
But not infinite gravity
Where reality is totality gone
At infinite angular velocity
These two departure lines, JD
Have reached the point of no return
That no singularity in the vacuum
Can return any semblance of truth
If any truth exists in a singularity of hole
That even existed in its conception
When the Singularity was coined
Because in truth the singularity
In all reality
Was the BHs demise in its formulation
So there you have another accolade JD
JDs infamous BH infinite angular velocity

All this fame is going to your head JD, the screws are beginning to rattle

Oct 25, 2018
The stupidity of infinite angular velocity


Dafuq are you on about, badger brains.

Oct 25, 2018
I would be curious to look at the simulation of a supermassive black hole merger in terms of its gravitational wave output. The kinds of GW signatures we have seen so far come from very small events comparatively speaking. I am just wondering if the GW from a truly massive merger could cause stellar disruption in the inner disk of the surrounding galaxy. This is turn could allow past supermassive BH mergers to be detected from long ago.

Just idle speculation while I wait for my compile to finish...

Low target incidence. You might have to wait a thousand years.

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