Ultrahigh energy cosmic ray nuclei from remnants of dead quasars

Abstract

We re-examine the possibility of ultrahigh energy cosmic rays being accelerated in nearby dormant quasars. We particularize our study to heavy nuclei to accommodate the spectrum and nuclear composition recently reported by the Pierre Auger Collaboration. Particle acceleration is driven by the Blandford-Znajek mechanism, which wires the dormant spinning black holes as Faraday unipolar dynamos. We demonstrate that energy losses are dominated by photonuclear interactions on the ambient photon fields. We argue that the local dark fossils of the past quasar activity can be classified on the basis of how source parameters (mass of the central engine and photon background surrounding the accelerator) impact the photonuclear interaction. In this classification it is possible to distinguish two unequivocal type of sources: those in which nuclei are completely photodisintegrated before escaping the acceleration region and those in which photopion production is the major energy damping mechanism. We further argue that the secondary nucleons from the photodisintegrated nuclei (which have a steep spectral index at injection) can populate the energy region below "the ankle" feature in the cosmic ray spectrum, whereas heavy and medium mass nuclei (with a harder spectral index) populate the energy region beyond "the ankle", all the way to the high energy end of the spectrum. In addition, we show that five potential quasar remnants from our cosmic backyard correlate with the hot-spot observed by the Telescope Array.

Particle acceleration in the superwinds of starburst galaxies

“…Curvature losses, in particular, can be important (Levinson 2000), resulting in γ-ray production. Photopair and photomeson losses might also play some role, especially for more massive black holes (e.g., Moncada et al 2017). In the case of a black hole of 10 6 M these cooling channels are negligible (Levinson & Boldt 2002).…”

Ultra-High-energy Cosmic Rays from beyond the Greisen–Zatsepin–Kuz’min Horizon

“…where G res is introduced as the resonance width. Adopting the same parameterization of  res and σ 0 as Unger et al (2015) 17 (see also, e.g., Moncada et al 2017), we obtain »  665 res , σ 0 = 5.0 × 10 −28 cm 2 , and G = 150 MeV res . By substituting Equation (23) into Equation (16), we obtain an analytical expression for the interaction rate:…”

Ultra high-energy cosmic rays from beyond the Greisen-Zatsepin-Kuz'min horizon

“…Adopting the same parameterisation of res and σ 0 as Unger et al (2015) 11 (see also, e.g. Moncada et al 2017), we obtain res ≈ 665, σ 0 = 5.0 × 10 −28 cm 2 , and Γ res = 150 MeV. By substituting Equation ( 23) into Equation ( 16) we obtain an analytical expression for the in-teraction rate:…”