VLBI observations of M87

On 1980 February 20 the authors conducted an 8-station intercontinental VLBI experiment in order to study the nucleus and jet of M87 at 1666.6 MHz in right circular polarization. The array was sensitive to structures from 0.001 to 0.1 arcsec. They made a hybrid map of the nucleus of M87, and also searched for compact structures within the knots of the jet. The map shows that the nucleus of M87 contains a one-sided jet. This morphology is similar to that observed in many compact extragalactic sources. The position angle of the nuclear jet is 290.5(+-1) degrees, which precisely matches that of the 20 arcsec jet. No bending of the jet through an angle greater than about 2 degrees is observed. The nucleus also contains a large component (>0.1 arcsec) which is elongated along the same position angle as the jet and has a flux density of roughly 1 Jy. This component is fully resolved by the vast majority of the (u,v) points and could not be mapped with standard techniques. (Auth.)