Cosmic ray generation by quasar remnants: constraints and implications

The quasar remnant cores of nearby giant elliptical galaxies NGC 4486 (M87) , 1399, 4649 and 4472 are the sites of supermassive (>10(9)M.) black holes. These objects are investigated as to the viability of the conjecture that they could harbour compact dynamos capable of generating the highest energy cosmic rays. For an accretion process involving an equipartition magnetic field near the event horizons of the underlying putative spun-up black hole s, the energy achievable in accelerating protons could well be greater than or equal to 10(20)eV for all these galaxies when only considering the drag induced by curvature radiation. Estimates of the spectral energy distribut ion (SED) of ambient core photons lead to the conclusion that the energy lo sses arising from photo-pion production in proton collisions with these tar get photons are relatively small for all but M87. For M87, the ambient phot on field is likely to be a limiting factor. Accretion rates of similar to 1 M. yr(-1), comparable to the Bondi rates and to the stellar mass-loss rate s, are associated with (>10(20)eV) cosmic ray generation in the other (elec tromagnetically dark) galactic core sites. If these sites are found to be s ources of such cosmic rays, it would suggest the presence of a global inflo w of interstellar gas all the way into the centre of the host galaxy.