SIMBAD references

We report on the detection of a soft spatially extended component of X-ray emission around four intermediate-redshift 3Cquasars observed with Chandra : 3C254, 3C263, 3C275.1 and 3C281. The bolometric luminosity of this emission ranges over 0.3-1.6x10⁴⁴ erg.s^–1, and extends to length-scales of over 350 kpc at the redshift of the quasar. The X-rays are most likely thermal emission from the intracluster medium of a cluster of galaxies around each quasar, which provides the working surface for the powerful radio lobes. Some X-ray emission is also seen to be associated with the radio plasma.