1999MNRAS.306..467I

We present results from ASCA and ROSAT HRI observations of the powerful radio galaxy 4C+55.16 at redshift 0.24. Extended soft X-ray emission is imaged by the ROSAT HRI. The X-ray brightness profile is sharply peaked on the radio galaxy, characteristic of a strong cooling flow. The X-ray spectrum obtained from ASCA is consistent with multiphase intracluster gas. There is evidence for an absorbed cool component as well as ambient cluster medium in the ASCA spectrum. A spectral fit, taking a cooling-flow component into account, gives a temperature of kT = 5.4_–0.9^+1.4 keV, metal abundance (0.5±0.1) Z_☉, excess absorption on the cool component, Δ N_H = 4.9_–1.3^+3.4 x 10²¹ cm^–2, and an absorption-corrected bolometric luminosity of 2.2 x 10⁴⁵ erg.s^–1 (H₀ = 50 km.s^–1.Mpc^–1, q₀ = 0.5). The mass-deposition rate is estimated to be ∼ 1100 M_☉.yr^–1 from the spectral analysis, in good agreement with that derived from imaging analysis of the ROSAT data when corrected for absorption. We tentatively identify a blue feature, seen ∼ 15 arcsec from the centre of the radio galaxy in a published optical image, as a gravitationally lensed arc. The inferred lensing mass is consistent with the gravitational mass derived from the X-ray data. The best estimate of the redshift of the lensed object is ∼ 1.5 (>0.7). All the observed properties suggest that the environment of 4C+55.16 is similar to known massive cooling-flow clusters. This is the first massive cooling flow to be found around a powerful, radio source with a compact, GHz-peaked spectrum core.