Paschen Alpha as a Probe of Relativistic Beaming

Extract

Is the theme of core-brightening by relativistic beaming, so useful for compact sources, helpful in explaining the nuclear properties of classical doubles? Certainly one can construct an attractive model - involving the usual beaming together with an anisotropic dust distribution at r ≲ 1 pc - to explain the differences in nuclear radio and optical properties of radiogalaxies as due differences in orientation with respect to us. There are clear predictions about the strength of broad Pα. Preliminary results indicate that this kind of model is not correct.