Observations of M87 at 5 GHz

M87 (Virgo A, 3C274), has been observed at 5 GHz with the Cambridge One-Mile telescope, with a resolution of $$6.5^{\prime\prime} \times 28^{\prime\prime}$$ arc. These observations did not include the extensive halo, but showed that the central region of the source consists of at least three components. The central component is unresolved and appears to coincide with the optical nucleus; the outer pair extend from a point about $$10^{\prime\prime}$$ arc south of the optical nucleus. These components are unresolved perpendicular to their extension axes. The north preceding component is related to the optical jet, but is more extended. The physical conditions in the radio components and the optical jet are investigated in the light of these new observations. It is concluded that the two outer components probably consist of a number of small sub-components, each confined by its supersonic passage through the gas in the galaxy. It is shown that the nuclear component probably has two sub-components, the smaller of these possibly producing the observed X-rays by the inverse Compton effect. The structure of the halo is used to derive some information about the past activity of the source.