Cosmogenic gamma rays and the composition of cosmic rays

Journal Article · Sat Oct 15 04:00:00 EDT 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.84.085019· OSTI ID:21607952

Ahlers, Markus ^[1]; Salvado, Jordi ^[2]

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1. C. N. Yang Institute for Theoretical Physics, SUNY at Stony Brook, Stony Brook, New York 11794-3840 (United States)
2. Departament d'Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, 647 Diagonal, E-08028 Barcelona (Spain)

We discuss the prospects of detecting the sources of ultrahigh energy (UHE) cosmic ray (CR) nuclei via their emission of cosmogenic {gamma} rays in the GeV to TeV energy range. These {gamma} rays result from electromagnetic cascades initiated by high energy photons, electrons, and positrons that are emitted by CRs during their propagation in the cosmic radiation background and are independent of the simultaneous emission of {gamma} rays in the vicinity of the source. The corresponding production power by UHE CR nuclei (with mass number A and charge Z) is dominated by pion photo production ({proportional_to}A) and Bethe-Heitler pair production ({proportional_to}Z{sup 2}). We show that the cosmogenic {gamma}-ray signal from a single steady UHE CR source is typically more robust with respect to variations of the source composition and injection spectrum than the accompanying signal of cosmogenic neutrinos. We study the diffuse emission from the sum of extragalactic CR sources as well as the point-source emission of the closest sources.

• OSTI ID: 21607952
• Journal Information: Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 8 Vol. 84; ISSN PRVDAQ; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
BOSONS
COSMIC GAMMA SOURCES
COSMIC NEUTRINOS
COSMIC RADIATION
COSMIC RAY SOURCES
ELECTROMAGNETIC INTERACTIONS
ELECTROMAGNETIC RADIATION
ELECTRONS
ELEMENTARY PARTICLES
EMISSION
ENERGY RANGE
FERMIONS
GAMMA RADIATION
GEV RANGE
HADRONS
INJECTION
INTAKE
INTERACTIONS
IONIZING RADIATIONS
LEPTONS
MASS NUMBER
MASSLESS PARTICLES
MATTER
MESONS
NEUTRINOS
NUCLEI
PAIR PRODUCTION
PARTICLE INTERACTIONS
PARTICLE PRODUCTION
PHOTONS
PHOTOPRODUCTION
PIONS
POINT SOURCES
POSITRONS
PSEUDOSCALAR MESONS
RADIATION SOURCES
RADIATIONS
SIGNALS
SPECTRA
TEV RANGE