Detection of X-ray emission from the giant radio lobes of CEN A

B. A. Cooke, A. Lawrence, G. C. Perola

Research output: Contribution to journalArticlepeer-review


The University of Leicester Sky Survey Instrument on the Ariel V X-ray astronomy satellite has detected, at high statistical significance, spatially extended X-ray emission from the giant radio lobes of Cen A. The combined emission of both lobes amounts to 1.3 (plus or minus 0.18) x 10 to the -10 erg/sq cm/s (2-10 keV), which corresponds to 3.7 x 10 to the 41 erg/s at a distance of 5 Mpc. Interpreting the X-rays as Inverse Compton Scattered photons of the microwave background by the radio-emitting electrons, we estimate the average strength of the magnetic field to be 0.7 microgauss, a value almost equal to the equipartition value computed with protons having the same energy content as electrons. There is strong evidence that the peaks of the X-ray emission do not coincide with the radio peaks but are further from the galaxy. This indicates that probably the magnetic field strength decreases by a factor 2-3 along the lobes away from the galaxy, whereas the electron density appears to be larger away from the galaxy than close to it.
Original languageEnglish
Pages (from-to)661-671
JournalMonthly Notices of the Royal Astronomical Society
Publication statusPublished - 1 Mar 1978


  • Compton Effect
  • Radio Sources (Astronomy)
  • Satellite Observation
  • Spaceborne Astronomy
  • X Ray Sources
  • Ariel 5 Satellite
  • Background Radiation
  • Electron Radiation
  • Magnetic Fields
  • Microwave Emission
  • Sky Surveys (Astronomy)

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