Subject: Is there a maximum surface brightness for an object?

To give off the maximum amount of light in the visible sprectrum a black body 
would likely give off most of its light somewhere in the ultraviolet part of 
the sprectrum.  Is this true?  At some point, if you go higher up in the 
electromagnetic sprectrum, the amount of visible light will drop being too far 
from the peak, even though the total amount of blackbody radiation over all the 
sprectrum continues to go up.

If an object is at a certain temperature, and it is functioning as a blackbody 
is it giving off its maximum surface brightness?  Or is it possible to increase 
surface brightness by having photons emitted through many 
transparent/transcluent layers.

If a blackbody at a certain is indeed giving off its maximum surface radiation, 
then I could resolve a mystery about the Crab Pulsar.  The Crab Pulsar is 16 
mag in visible light.  If it were emitted all that light from the surface of 
the pulsar alone it would have a surface brightness 24 magnitudes brighter than 
our Sun (assuming a 20 km diameter).  I don't think that is possible.

I believe that x-ray or gamma-ray light from the pulsar is stimulating and 
lightup up a nebula of gas surrounding the pulsar.  Up to some fraction of the 
Sun's diameter, this nebula could have a surface brightness as bright as the 
Sun and drop sharply after that.  Do you think this is true?

Re: Is there a maximum surface brightness for an object?