Accretion disk around galaxy NGC 4261

[JeffOCA]

Hello,

When you look at the accretion disk around NGC 4261 (see here), you can read that the dark, dusty disk represents a cold outer region which extends inwards to an ultra-hot accretion disk with a few hundred million miles from the suspected black hole.
So, from the outside, you have successively a bright ring, then a dark dusty ring and "an ultra-hot accretion disk" very close to the center black hole itself.

My question : due to the ultra-hot temperature in the accretion disk, the dark material (dust) is extremely heated and, so, should radiate in a very bright way (UV and/or X-rays). Why not ?

Regards
JF

 

[Chronos]

Here is an X ray image of NGC 4261 http://chandra.harvard.edu/photo/2003/ngc4261/

 

[JeffOCA]

Ok, the picture link I posted is taken at visible wavelengths that why dust material is not bright. Am I right ?

Regards
JF

 

[Chronos]

Yes. Dust tends to radiate at the frequency of light it receives.