Simulation Explains Supermassive Black Holes

Spy der Mann writes "Using a new computer model of galaxy formation, researchers from Carnegie Mellon University have shown that growing black holes release a blast of energy that fundamentally regulates galaxy evolution and black hole growth itself. According to its creators, 'the model explains for the first time observed phenomena and promises to deliver deeper insights into our understanding of galaxy formation and the role of black holes throughout cosmic history'. Hi res pictures and animations (divX) are also available."

Comments

Reflecting the /. effect?

[bagel2ooo]

Well, after the incident with the British Royal Navy and the 38MB Powerpoint file linked to the front page. Now we get to see if the /. effect will cause the packets to coalesce and turn their server into a matter crushing supermassive black hole itself. I guess 22MB DivX is better than linking MPEG. :)

Coral Cache Mirrors

[Agret]

Medium Image
Large Image
Medium Quality Movie
High Quality Movie

animations

[selderrr]

/me thinks they used iTunes screensaver for this :-)

Pretty Interesting

[mbrother]

This is my area of expertise, from the observational side. I've just finished writing a proposal (due today!) to observe "post-starburst quasars" in the infrared with the Spitzer Space Telescope. These are quasars that still show clear signs of massive starbursts, observations that can in principle test simulations like the ones discussed in the article. I've seen Di Matteo give a talk on this topic a year or two ago, and she strikes me as very good. I'm going to have to check out the new work closely -- I have suspicions that their explanation will fail in some details. But that's what makes science fun, finding the problems with ideas and fixing them, or forcing everyone to move on.

Re:Pretty Interesting

[js7a]

so, how long are quasars resulting from supermassive black hole collisions expected to last?

Re:Pretty Interesting

[mbrother]

There are limits to quasar ages based on demographic arguments (the relic holes we see today compared to historical quasar activity and assumptions about the efficiency of the matter to energy conversion). The upper limit is on order of 100 million years or so. I know the timescale for "blowing out" gas/dust on Galactic scales from a powerful quasar is much shorter than that, more like 100,000 years, so I'm going to have to see the jounral article and see what they're saying in this paper. Big difference between those two numbers. Keep in mind that even 100 million years is relatively short compared to a unverse age of 13.7 billion years and may be the "short" timescale discussed.

Re:Pretty Interesting

[Ev0lution]

This is my area of expertise, from the observational side

This was my area of expertise too, although I've now left astronomy. I worked indirectly with Volker Springel, who is extremely good (his simulation code, GADGET, was depressingly better than mine!). The bit that's new is the treatment of radiative transfer, which is extremely hard to model (the full treatment is a time-dependent function of six variables, so you have to simplify it somehow). Doing it well is an achievement in itself, but it's also where the numerics are likely to be wrong. The non-radiative aspect of the simulations isn't new (I did similar simulations for galaxy clusters in my thesis, and although I did them better - at the time - it wasn't new then).

Re:Pretty Interesting

[mbrother]

No, the black holes CAN'T splatter into pieces. They're too massive, their gravity too strong. All the "crap" around them -- gas, dust -- that is the fuel of the quasar -- that stuff surely does spew all over. The basic accretion process, when things settle down and merg, is for that material to form a flattened disk. When you see a quasar, it is the intense radiation from this hot disk that does all the shining. The black hole just provides the gravity. There may also be relativistic jets shooting out the spin axis, but their formation is not well understood. Neither are the less collimated outflows from around quasars (one of the reasons I'm suspicious about their results -- they're dealing with a broad brush and could be right on that level but we surely don't understand a lot of the details even on an empirical, observational level).

I've got some lecture slides on active galaxies (powerpoint) up at my astronomy website. Look at: This link. There are some some real images, and some artists renditions, you might like. I've just used the powerpoint web format, so it looks crappy in anything but explorer. Sorry.

A great step for xscreensaver

[Jammet]

Now we can replace the galaxy screensaver with this calculation, and it entertain even more!

Re:Cool

[piquadratCH]

Seriously, I think everyone loves black holes.

No. They suck.

Re:Cool

[AstrumPreliator]

I don't know about that. My last girlfriend told me her black hole was "off limits".

More Information

[NEOtaku17]

Here are tons of the most recent research papers on black holes. Definitely an good read for anyone with an interest in physics.

Re:Hmm

[mbrother]

Astronomy does pretty well with women, at least compared to other hard sciences. At the undergraduate level, it looks to be close to 50/50. Last year I think we had more female applicants for our summer REU program than males. We're going to admit more women than men into our graduate program this year, too. At the more senior levels, there are fewer women, but the numbers more or less match the historical demographics. My PhD advisor was female, and I have lots of female collaborators and a female grad student. Di Matteo isn't too old -- my generation, 30s. Physics, on the other hand, is still having its problems...

Resolution espected

[FrenchNeal]

They should have released images in 1024x768, 1280x1024 etc... to make it better wallpaper!

Bold claims

[ralphclark]

Surely the word "may" belongs in there somewhere?

Re:Whoa, massive blackhole...

[Flendon]

i always have wondering since nothing can escape then why is it emitting something out of it? Just a thought.

The blackholes don't actually emit anything. The accretion disk is what does the emitting. Imagine water going down a drain. Most of the matter approaching a blackhole is not on a direct collision course but rather the blackhole sucks it close where it spirals downward. The spiraling excites the atoms creating huge bursts of energy, sometimes enough to blast nearby matter out of the gravitational field.

Implications for our own galaxy?

[kcbrown]

If I'm not mistaken, the Milky way and the Andromeda galaxy will collide (or have a near-miss, I'm not sure which) about a billion years hence.

If both galaxies have black holes at their centers, and the simulation is correct, then I have to wonder what the consequences will be for life within either galaxy, as I would imagine the burst of radiation from the collision of the black holes (and the resulting quasar) will be deadly.

Anyone wanna chime in with some numbers?

Maybe the Pierson's Puppeteers have the right idea after all...

Re:Implications for our own galaxy?

[mbrother]

The high supernova rate resulting from the burst of star formation is likely more of a problem than a central quasar, especially since the star formation can take place outside of the Galactic center. I give my intro astronomy students a problem to computer what the Galactic core would look like if it was a quasar and there was no intervening gas/dust (a really big if, since there is a lot of obscuration now).

Quasars can be 1000 times more luminous than an entire galaxy. The absolute magnitude of such a luminous quasar would be about M = -28.5. If the black hole in the center of our galaxy became a quasar, and obscuring gas and dust did not dim it, what would the apparent magnitude of the galactic core be? Think about the answer and what that would look like in the sky.

The answer is a magnitude of -13.9, about the same as the full moon. It would be more concentrated that the light of the moon, and you'd be able to see it in the day time. But, as I said, intervening gas/dust would diminish it's light, and the Milky Way and Andromeda do not have black holes massive enough to shine as brightly as my example. Our atmosphere would also be there to protect us from X-rays and UV, much as it does now.

Re:Implications for our own galaxy?

[sploo22]

A collision between galaxies is not exactly as dramatic as you seem to think it would be. Remember, stars are light-years apart. Actual collisions between stars would be very rare, and unless the black holes come within an incredibly tiny distance they would just slingshot around each other in a hyperbolic orbit and keep going. The real issue is that large numbers of stars would be flung off into space in the process, but I'd say that if there are any humans still alive then, a boring night sky is something they can live with.

Re:Implications for our own galaxy?

[Pedrito]

If I'm not mistaken, the Milky way and the Andromeda galaxy will collide

You are correct. And a simulation of that can be found here in mpeg format.

Re:Implications for our own galaxy?

[kamikasei]

This is gone over in one of Alastair Reynolds' books - Redemption Ark I believe it was. From what I can remember the main problem wasn't colliding stars but colliding gas clouds and such, prompting new star formation, leading quickly to supernovas, which due to their size or location or both would basically sterilize most of the galaxy. Not quite a boring night sky...

Re:Whoa, massive blackhole...

[Baudelaire76]

The blackholes don't actually emit anything. The accretion disk is what does the emitting.

Actually, black holes do emit. It's called Hawking radiation. But you're right in that what we see is coming from the accretion disk.

Re:Whoa, massive blackhole...

[mbrother]

The origin of the X-rays are not well understood, but are thought primarily to come from upscattering of thermal photons in a very hot atmosphere above the accretion disk. All the light basically comes from the stuff right around the black holes moving at relativistic speeds, not the black holes themselves.

Re:Fears put to rest

[m50d]

Eventually the accreation disk (that does the radiating) will all get sucked in, and then there will be no more "wind", so more matter can be pulled in.

Re:Hmm

[IWannaBeAnAC]

But then, pure maths seems to be doing OK with women, at least at undergraduate/early graduate levels. So its not maths per se that's the problem. Is it simply inertia? Maybe astronomy 'simply' achieved a critical mass of women, so new female students don't feel like they're joining a club of crotchety old men?

Weapons of Mass Suction

[gelfling]

Quick let's declare war on it.

Re:Cool

[Liquidrage]

"...have shown that growing black holes release a blast of energy"

And apparently they blow as well.