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We present J, H and K-band spectroscopy of Cygnus A, spanning 1.0–2.4 μm in the rest-frame and hence several rovibrational H[sub 2], H recombination and [Fe ii] emission lines. The lines are spatially extended by up to 6 kpc from the nucleus, but their distinct kinematics indicate that the three groups (H, H[sub 2] and [Fe ii]) are not wholly produced in the same gas. The broadest line, [Fe ii]λ1.644, exhibits a non-Gaussian profile with a broad base (FWHM≃1040 km s[sup -1]), perhaps because of the interaction with the radio source. Extinctions to the line-emitting regions substantially exceed earlier measurements based on optical H recombination lines. Hard X-rays from the quasar nucleus are likely to dominate the excitation of the H[sub 2] emission. The results of Maloney, Hollenbach & Tielens are thus used to infer the total mass of gas in H[sub 2] v=1–0 S(1)-emitting clouds as a function of radius, for gas densities of 10[sup 3] and 10[sup 5] cm[sup -3], and stopping column densities N[sub H]=10[sup 22]–10[sup 24] cm[sup -2]. Assuming azimuthal symmetry, at least 2.3×10[sup 8] M[sub ⊙] of such material is present within 5 kpc of the nucleus, if the line-emitting clouds see an unobscured quasar spectrum. Alternatively, if the bulk of the X-ray absorption to the nucleus inferred by Ueno et al. actually arises in a circumnuclear torus, the implied gas mass rises to ∼10[sup 10] M[sub ⊙]. The latter plausibly accounts for 10[sup 9] yr of mass deposition from the cluster cooling flow, for which M≃ 10M[sub ⊙]yr[sup -1] within this radius. [ABSTRACT FROM AUTHOR]

We present integral field spectroscopy of a small sample of radio-loud quasars at intermediate redshift (0.26