Abstract We have obtained very high angular resolution (a few milliarcseconds or sub-parsec-scale) Very Long Baseline Array (VLBA) and European Very Long Baseline Interferometry Network (EVN) radio continuum images of the nucleus in the barred spiral galaxy NGC 7479, to search for possible nuclear emission on parsec scales. The observations were taken using phase referencing. Previous Karl G. Jansky Very Large Array and Multi-Element Radio Linked Interferometer Network observations revealed a large jetlike structure, apparently emanating from the nucleus, and unresolved nuclear emission at 0 . ″ 1 (≈15 pc at the assumed distance of 32 Mpc) scale, respectively. Our sensitive new VLBA and EVN images resolve the previously unresolved nuclear source and reveal two distinct emission regions (very long baseline interferometry (VLBI) components) that are separated by about 30 mas. We also report an apparent change in separation of the two main emission regions over the 10 yr between EVN and VLBA observations, implying relativistic radio jet motion or changes in shock illumination of gas by a nuclear wind. We measure the spectral indices and brightness temperatures of the VLBI components and discuss possible physical causes of the observed emission.
Laine et al. (Tue,) studied this question.