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Study of Flat-spectrum Radio Quasars and BL Lacertae Objects as Sources of Diffusive Ultrahigh-energy Cosmic Rays

delete2026-05-20
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PRE
AI
S
Swaraj Pratim Sarmah *
U
Umananda Dev Goswami
DOI:10.3847/1538-4357/ae64ecdelete
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Abstract

Abstract

En 中文
We examine whether flat-spectrum radio quasars (FSRQs) and BL Lac objects can act as plausible astrophysical sources of diffuse ultrahigh-energy cosmic rays (UHECRs). Using realistic luminosity-dependent density evolution functions derived from observed gamma-ray luminosity functions for FSRQs and BL Lac objects, we calculate the redshift evolution of the cosmic-ray source population through integrated luminosity functions. The diffuse UHECR flux from these sources is modelled by propagating nuclei through extragalactic space, including energy losses from interactions with cosmic photon backgrounds. The resulting UHECR spectra are compared with observational data from the Pierre Auger Observatory and the Telescope Array, with fluxes normalized at reference energies. We also construct illustrative full sky maps of the integral UHECR flux from 10 to 100 EeV using the HEALPix framework, assuming a uniform distribution of synthetic sources and including energy-dependent magnetic diffusion. Our results show that although both FSRQs and BL Lac objects can reproduce the observed UHECR flux, the FSRQ scenario is disfavoured by anisotropy and an inconsistent source density, while BL Lac objects remain consistent with observations.
Keywords:
ACTIVE GALACTIC NUCLEI
LUMINOSITY FUNCTION
COSMOLOGICAL EVOLUTION
ANALYTIC CALCULATIONS
EXPANDING UNIVERSE
MAGNETIC-FIELDS
PROPAGATION
SAMPLE
BLAZARS
ACCELERATION

Journal

Astrophysical Journal cover
Astrophysical Journal
IF:
5.4
Papers:
8.3W
Citations:
32.0W

Organization

I
indian institute of technology (iit) - guwahati
Scholars:
3.2K
Papers: 3.2K
Citations: 2
I
indian institute of technology system (iit system)
Scholars:
9.3W
Papers: 9.9W
Citations: 93
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