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A cooling flow around the quasar 3C 48

1987; Oxford University Press; Volume: 228; Issue: 4 Linguagem: Inglês

10.1093/mnras/228.4.963

1365-2966

A. C. Fabian, C. S. Crawford, R. M. Johnstone, P. Thomas,

Astrophysics and Star Formation Studies

Spatially-resolved optical spectra of the nebulosity around the quasar 3C 48 show forbidden oxygen line emission extending to a radius of ∼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 to indicate a gas density of at least 3×107 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 ∼3×108M⊙. The commonly proposed galaxy collision or merger hypothesis for quasar nebulosity leads to the clumps being unconfined so that they rapidly disperse. A much higher total mass of cold gas (>1011M⊙) is required so that the nebulosity can last for a collision time-scale and widespread emission can occur. As this far exceeds the mass of gas in normal galaxies, a galaxy collision is an unlikely explanation for 3C 48. A cooling flow around 3C 48 and other quasars is consistent with them lying in either poor or rich clusters and, through accretion, provides a direct link between the quasar nucleus and its environment.