PHYSICAL EFFECTS FROM THE INTRACLUSTER GAS
ON CLASSICAL DOUBLE RADIO GALAXIES
LOCATED IN CLUSTERS OF GALAXIES

J.P. Vallée
1981, Astrophysical Letters, 22, 63-68

J.P. Vallée & A.H. Bridle
1982 Astrophysical Journal, 253, 479-484


X-ray images of  1 square degree each 
were acquired with the Einstein Observatory satellite in 1979, 
using the Imaging Proportional Counter with 2-arcmin resolution,
of 3 wide classical-double radio-emitting galaxies
located inside the intracluster thermal x-ray gas.



Physics: The observations revealed an interaction between the relativistic radio gas
and the thermal x-ray gas. In Abell cluster A1763,
the thermal gas withstood the equipartition pressure in the double radio
lobes of the expanding relativistic gas,
but the ridge of the radio gas showed a small deformation attributed
to the motion of the optical galaxy across the x-ray cluster gas.



Model: Assuming hydrostatic equilibrium of the hot gas with cluster gravity,
the total amount of mass in the x-ray gas within a radius of 1.4 Mpc
is comparable to the mass of all the optical galaxies,
but an additional dark mass is needed to bind the cluster.