How Plasma Composition affects the relativistic flows and the emergent spectra

It has been recently shown that transonic electron positron fluid is the least relativistic, compared to the fluid containing finite proportion of baryons. We compute spectra from these flows in general relativity (GR) including the effect of light bending. We consider the bremsstrahlung process to supply the seed photons. We choose accretion in the advective domain, and for simplicity the radial accretion or Bondi type accretion. We show that electron positron accreting flow produces the softest spectra and the lowest luminosity.