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The Very Long Baseline Array has been used at 15 GHz to image the milliarcsecond structure of the Seyfert galaxies Mrk 231 and Mrk 348 at two epochs separated by about 1.7 yr. Both galaxies contain parsec-scale double radio sources whose components have brightness temperatures of 10^9-10^{11} K, implying that they are generated by synchrotron emission. The nuclear components are identified by their strong variability between epochs, indicating that the double sources represent apparently one-sided jets. Relative component speeds are measured to be ~0.1c at separations of 1.1 pc or less (for H_0 = 65 km/s/Mpc), implying that parsec-scale Seyfert jets are intrinsically different from those in most powerful radio galaxies and quasars. The lack of observed counterjets is most likely due to free-free absorption by torus gas, with an ionized density n_e > 2 X 10^5 cm^{-3} at T~8000 K, or n_e > 10^7 cm^{-3} at T~10^{6.6} K, in the inner parsec of each galaxy. The lower density is consistent with values found from X-ray absorption measurements, while the higher temperature and density are consistent with direct radio imaging of the NGC 1068 torus by Gallimore et al.
Radio outflows of extents ranging from a few parsecs to a few kiloparsecs are present in Seyfert and LINER galaxies that make up the `radio-quiet AGN class. AGN jets and/or starburst superwinds have been suggested to produce these outflows. We presen
We present 18-cm radio maps of four Seyfert nuclei, Mrk 1, Mrk 3, Mrk 231 and Mrk 463E, made with the European VLBI Network (EVN). Linear radio structures are present in three out of four sources on scales of ~100 pc to ~1 kpc, and the 20-mas beam of
(Abridged) We consider the polarization properties of optically thin synchrotron radiation emitted by relativistically moving electron--positron jets carrying large-scale helical magnetic fields. In our model, the jet is cylindrical, and the emitting
We conducted radio detection observations at 8.4 GHz for 22 radio-loud broad absorption line (BAL) quasars, selected from the Sloan Digital Sky Survey (SDSS) Third Data Release, by a very-long-baseline interferometry (VLBI) technique. The VLBI instru
We have discovered kiloparsec-scale extended radio emission in three narrow-line Seyfert 1 galaxies (NLS1s) in sub-arcsecond resolution 9 GHz images from the Karl G. Jansky Very Large Array (VLA). We find all sources show two-sided, mildly core-domin