X‐Ray–emitting Atmospheres of B2 Radio Galaxies

We report ROSAT PSPC spatial and spectral analysis of the eight B2 radiogalaxies NGC 315, NGC 326, 4C 35.03, B2 0326+39, NGC 2484, B2 1040+31, B21855+37, and 3C 449, expected to be representative of the class of low-powerradio galaxies. Multiple X-ray components are present in each, and the gascomponents have a wide range of linear sizes and follow an extrapolation of thecluster X-ray luminosity/temperature correlation, implying that there is norelationship between the presence of a radio galaxy and the gas fraction of theenvironment. No large-scale cooling flows are found. There is no correlation ofradio-galaxy size with the scale or density of the X-ray atmosphere. Thissuggests that it is processes on scales less than those of the overall gaseousenvironments which are the major influence on radio-source dynamics. Theintergalactic medium is usually sufficient to confine the outer parts of theradio structures, in some cases even to within 5 kpc of the core. In the caseof NGC 315, an extrapolation suggests that the pressure of the atmosphere maymatch the minimum pressure in the radio source over a factor of about 40 inlinear size (a factor of about 1600 in pressure).Comment: 34 pages, including 10 figures, using aasms4.sty To appear in the Ap