Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultrahigh energy cosmic ray nuclei from remnants of dead quasars   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.

26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
24
The categories of this paper are: dg-ga
2
The categories of this paper are: math