The Apparent Angular Size - Frequency Dependence in ~3000 Parsec-scale Extragalactic Jets


الملخص بالإنكليزية

The upper envelope of the amplitude of the VLBI visibility function usually represents the most compact structural pattern of extragalactic radio sources, in particular, the core-jet morphologies. By fitting the envelope to a circular Gaussian model in ~3000 parsec-scale core-jet structures, we find that the apparent angular size shows significant power-law dependence on the observing frequency (power index n = -0.95 pm 0.37). The dependence is likely to result from synchrotron self-absorption in the inhomogeneous jet and not the free-free absorption (n = -2.5), nor the simple scatter broadening (n leq -2).

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