Matter in accretion disks VS higgs-boson at CERN

[David Levy]

The 10 µas figure is the angular size of the black hole radius (which would be about 12 million km).

 

The 37 µas figure is the diameter of the radio source - the accretion disk and / jets (depending which models are correct).

 

 

Thanks

 

So, the radius of the SMBH is 12 Million Km, while the diameter of the accretion disk is:

 

37 /12 * 12 Million Km = 37 Million Km

 

Hence, the radius of the accretion disk should be 37/2 Million Km = 18.5 Million Km.

 

Do you agree with that?

 

[Strange]

 

Thanks

 

So, the radius of the SMBH is 12 Million Km, while the diameter of the accretion disk is:

 

37 /12 * 12 Million Km = 37 Million Km

 

Hence, the radius of the accretion disk should be 37/2 Million Km = 18.5 Million Km.

 

Do you agree with that?

 

 

 

That is the size of the radio source. I don't know how that relates to the accretion disk which is, I assume, much larger.

[David Levy]

That is the size of the radio source. I don't know how that relates to the accretion disk which is, I assume, much larger.

 

Can you please give me your best understanding/estimation for the radius of the accretion disk.

Could it be in the range of 100 Million Km?

Edited March 31, 2017 by David Levy

[Strange]

I have no idea.

[David Levy]

Thanks

[David Levy]

What is the radius of Sagittarius_A* Event horizon?

I couldn't find a direct number, however based on the following info its quite easy to calculate.

https://en.wikipedia.org/wiki/Sagittarius_A*

First noticed as something unusual in images of the center of the Milky Way in 2002,[34] the gas cloud G2, which has a mass about three times that of Earth, was confirmed to be likely on a course taking it into the accretion zone of Sgr A* in a paper published in Nature in 2012.[35] Predictions of its orbit suggested it would make its closest approach to the black hole (a perinigricon) in early 2014, when the cloud was at a distance of just over 3000 times the radius of the event horizon (or ≈260 AU, 36 light-hours) from the black hole.

Hence:

Radius of Sagittarius_A* Event horizon = 36 light-hours / 3000

36 light-hours = 36 * 3.88531026 e10 kilometers

Radius of Sagittarius_A* Event horizon = 46.6237 * e7 kilometers = 460 Million Km.

However, the accretion disk must be located outwards the radius of Sagittarius_A* Event horizon.

Therefore, this info should give us an indication for the minimal radius of the accretion disk.

Is it correct?

Edited April 1, 2017 by David Levy

[Strange]

The radius is about 1.2x10¹⁰ m.

 

See here: https://en.wikipedia.org/wiki/Schwarzschild_radius#Parameters

And here: http://www.wolframalpha.com/input/?i=Schwarzschild+radius+4000000+solar+mass

 

The closest stable orbit is, I think, at twice the Schwarzschild radius. So any matter closer than that is falling into the black hole. But I assume that would still be included as part of the accretion disk so the minimum radius is the radius of the event horizon.

Your conversion is incorrect for some reason.

36 light-hours / 3000 = 1.295x10¹⁰ m

See here: http://www.wolframalpha.com/input/?i=36+light-hours+%2F+3000+in+metres

 

Looks like you have the wrong number for light hours: http://www.wolframalpha.com/input/?i=1+light-hours++in+metres

[David Levy]

Thanks

 

The radius is about 1.2x10¹⁰ m.

 

Hence:

The Radius of Sagittarius_A* Event horizon = 12 Million Km.

However, that exactly the radius of its SMBH mass.

 

 

The 10 µas figure is the angular size of the black hole radius (which would be about 12 million km).

 

Is it O.K.?

 

I had the impression that the location of event horizon should be quite outwards than the SMBH radius mass.

It is just on the edge. So, some SMBH mass at the edge could technically drift outside the event horizon.

In this case, could it be that some light from the SMBH mass might escape from the event horizon?

 

Edited April 1, 2017 by David Levy

[Strange]

 

Thanks

 

 

Hence:

The Radius of Sagittarius_A* Event horizon = 12 Million Km.

However, that exactly the radius of its SMBH mass.

 

 

Obviously.

 

 

I had the impression that the location of event horizon should be quite outwards than the SMBH radius mass.

It is just on the edge. So, some SMBH mass at the edge could technically drift outside the event horizon.

In this case, could it be that some light from the SMBH mass might escape from the event horizon?

 

I don't know what you mean by "SMBH radius mass". The radius of the event horizon of a black hole is proportional to its mass. Nothing can escape the event horizon.

 

I think you need to read this https://en.wikipedia.org/wiki/Black_hole to clear up your misunderstandings. (Probably also available in your native language.)

[David Levy]

Well, it's quite disappointing that the Accretion disk radius is so mysterious (for all of us at any language) .

 

I hope to find it later on.

Edited April 1, 2017 by David Levy

[Strange]

The problem is that it is very far away and largely hidden by dust clouds and so on. I also doubt there is a "hard" outer radius to the accretion disk. It is mainly gas and so will just get thinner and thinner with distance.

 

http://www.pppl.gov/news/2016/12/better-way-simulate-accretion-supermassive-black-hole-center-milky-way-developed-pppl

https://arxiv.org/abs/1608.07911