Slide 35 of 48
Notes:
Substituting for Omega into the previous SSA equation in terms of F_nu, we derive the expression above. Then re-arranging and inserting values for numerical constants we find the expression for R shown.
This expression for R shows that R is proportional to nu^(-5/4), ie as the source size increases, the frequency at which the self-absorption occurs decreases (moves to longer wavelengths).
Thus if a source is large and emits strongly in the radio, SSA is an important process (eg. in extended, lobe-dominated radio galaxies).
But how important is it in a compact X-ray source?
