The connection between radio-quiet active galactic nuclei and the high/ soft state of X-ray binaries

Thomas J. Maccarone, Elena Gallo, Rob Fender

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A large sample of active galactic nuclei (AGN) studied here shows a 'quenching' of the radio emission that occurs when the luminosity is from a few per cent to about 10 per cent of the Eddington rate, just as is seen in the high/soft state of X-ray binaries. The result holds even when the sample of AGN includes no narrow line Seyfert 1 galaxies (the systems most commonly suggested to be the analogue of the high/soft state). This adds substantially to the body of evidence that AGN show the same spectral state phenomenology and related disc-jet coupling as the stellar mass accreting black holes. That the power-law correlation between X-ray and radio luminosity is the same in both AGN and X-ray binaries and extends below 10-7 LEDD strengthens the argument that there is no fundamental difference between the low/hard state and the so-called quiescent state in X-ray binaries. We also discuss possible reasons for the scatter in the radio to X-ray luminosity correlation in the AGN.

Original languageEnglish
Pages (from-to)L19-L24
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - Oct 21 2003



  • Accretion, accretion discs
  • Galaxies: Seyfert
  • Galaxies: jets
  • Quasars: general
  • X-rays: binaries

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