Discovery of a nuclear counterjet in NGC 1275: A new way to probe the parsec-scale environment

We present a high dynamic range 22 GHz VLBI image of the core of NGC 1275 (3C 84) and discuss the evolution of some of the features seen in previous 22 GHz images. In addition, our image reveals for the first time a feature which is part of the (northern) counterjet. It is extended, and comparison with an 8 GHz image of Walker, Romney, & Benson (1994), which also shows the northern component, indicates that it has a strongly inverted spectrum, unlike the southern features. A simple explanation is that gas in a roughly toroidal or disklike region obscures the counterjet through free-free absorption. Simultaneous multifrequency VLBI observations may provide a new method of probing the parsec-scale environment in nearby galactic nuclei.