SIMBAD references

It has recently been suggested that Compton downscattering may give rise to the broad iron lines seen in the X-ray spectra of Seyfert 1 galaxies. This challenges the standard model, in which these lines originate from the innermost regions of the black hole accretion disk with Doppler shifts and gravitational redshifts giving rise to the broadened line profile. Here we apply observational constraints to the Compton downscattering model for MCG-6-30-15 and NGC 3516, the two best cases to date of Seyfert galaxies with relativistically broad lines. We show that the continuum source in MCG-6-30-15 required by the constrained model violates the blackbody limit. In the case of NGC 3516, only a very small region of parameter space is compatible with the constraints. Hence, we conclude that the Comptonization model is not a viable one for the broad line seen in these two objects. The accretion disk model remains the best interpretation of these data.