Photon densities within galtactic disc compared to CMB

[UHECRon]

I am interested in what the average photon densities are within galactic environments due to non CMB sources. In extra galactic environments, the CMB certainly dominates, however as you enter more dense and luminous areas (e.g. , the galactic disc) broad spectrum photon densities from local sources must climb. My question is how does this compare on average to CMB?

I ask as the answer may have implications on cosmic ray phenomenology.

 

[Drakkith]

I ask as the answer may have implications on cosmic ray phenomenology.

In what way?

 

[UHECRon]

I was wondering about the rates of photo-pion production in the galactic disc as opposed to those more traditionally calculated in extra galactic spaces. The thought being that a significant enhancement of attenuation of Ultra high energy cosmic rays in the regime could help to explain some discrepancies observed in both flux and composition at these extreme energies in the northern and southern hemispheres.

A lazy literature search hasn't turned up much on broad spectrum photon intensities in galactic environments so I was hoping someone would point me in a helpful direction.

 

[Drakkith]

I see. Well, I doubt I can help you at all. Best of luck on your search!

 

[UHECRon]

Thanks! Hope I find something. If I do, I will report it here.

If anyone reads this and has any insights, I would be most thankful for some information.