A cooling flow around the quasar 3C48

Spatially-resolved optical spectra of the nebulosity around the quasar 3C48 show forbidden oxygen line emission extending to a radius of approx. 30 kpc. Assuming that the gas is photoionized by the quasar nucleus which has a spectrum unabsorbed shortward of 91.2 nm, the relative strengths of the [O III] and [O II] lines are interpreted as indicating a gas density of at least 3 x 107 m-3. The observed gas is in clumps which are thinner than about 10 pc and is at a pressure consistent with a cooling flow such as that around the central galaxy in the poor cluster MKW3s. The total mass of observed gas is approx. 3 x 108 solar masses. (author)