Questions tagged [accretion-discs]
Questions regarding disks of gas, dust, and plasma around a central object, such as a black hole, which takes in the matter.
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What is it exactly about these flares of infrared light from Sgr A* that "confirms" it is a supermassive black hole?
CNET.com's SCI-TECH
Scientists confirm a 'supermassive black hole' at the heart of our galaxy
It's "mind-boggling", they say.
This links to Astronomy.com's Scientists finally confirm the Milky Way ...
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How did they make a video of the center of the galaxy, and what is it exactly that's flashing there?
The ESA video ESOcast 173: First Successful Test of Einstein’s General Relativity Near Supermassive Black Hole includes a clip of images of stars at the center of our galaxy orbiting around SgrA*, a ...
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How will they know when to start taking the picture of the black hole at the center of the Milky Way?
@csm's answer to Why not take a picture of a closer black hole? points out that it's necessary for the supermassive black hole at the center of a galaxy to be actively feeding for it to generate a ...
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What defines the plane of an accretion disk around a black hole?
The question Do we know at which angle the Event Horizon Telescope will look at the accretion disk of Sagittarius A*? about just how close to edge-on we would be viewing any accretion disk around the ...
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Why would the merger of spinning black holes within the accretion disk of a supermassive black hole cause them to "shoot straight up" out of the disk?
I just tried to read the new New York Times article Two Black Holes Colliding Not Enough? Make It Three which links to the new 25-June-2020 Physical Review Letter Graham et al. Candidate ...
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What enhances the capture and merge rates of pairs of small black holes orbiting around supermassive black holes?
I just tried to read the new New York Times article Two Black Holes Colliding Not Enough? Make It Three which links to the new 25-June-2020 Physical Review Letter Graham et al. Candidate ...
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Accretion disks - why are they disk-shaped, rather than spherical?
So, the theory (briefly) about accretion disks is that stuff falling into the black hole will most likely not fall straight into it but will miss it and go into orbit, perhaps for a long time, perhaps ...
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How are microlensing events used to constrain the size of innermost stable circular orbits around spinning black holes?
The third paragraph of the introduction to the ArXiv preprint Constraining Quasar Relativistic Reflection Regions and Spins with Microlensing says:
Quasar microlensing has significantly improved our ...
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If a black hole does not emit light, how can one take a picture of the black hole itself?
There's some discussion that the image composed by the Event Horizons Telescope is really just an accretion disk. To "take an image" of something, you need the light reflecting off of the surface of ...
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Did the earth form outside the solar system?
Why isn't it possible that the earth formed outside the solar system and got attracted later by the Sun?
I just need arguments to defeat this hypothesis.
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Quasar mass and accretion rates
This page on Wikipedia -- Quasars mentions that the "The largest known [quasar] is estimated to consume matter equivalent to 600 Earths per minute". However, there is no citation for this comment. How ...
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How do rocky objects between 1cm and 1m accrete to form planetesimals?
I am having a hard time gaining an intuitive understanding of some of the middle stages of planetary formation from a protoplanetary accretion disk.
I understand that microscopic dust particles may ...
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Angular momentum in planetary disk formation
Reading about the formation of planetary disks, one of the major problems, it seems like, is the evacuation of angular momentum. Aparently planets can't form with the amount o angular momentum the ...
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How does gas in accretion disks of supermassive black holes create orbital torques on smaller black holes within the disks causing them to migrate?
This answer to What enhances the capture and merge rates of pairs of small black holes orbiting around supermassive black holes? links to Migration Traps in Disks Around Supermassive Black Holes which ...
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What does "synchrotron emission from relativistic electrons in equipartition with a ∼1.5 mG magnetic field" mean?
I've heard of the equipartition theorem in the context of thermodynamics.
But I don't understand how either "synchrotron emission" or "relativistic electrons" can be in "...
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