Fermi-LAT γ-ray anisotropy and intensity explained by unresolved radio-loud active galactic nuclei

Journal Article · Sat Nov 01 04:00:00 EDT 2014 · Journal of Cosmology and Astroparticle Physics

DOI:https://doi.org/10.1088/1475-7516/2014/11/021· OSTI ID:22375750

Mauro, Mattia Di; Cuoco, Alessandro; Donato, Fiorenza ^[1]

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1. Dipartimento di Fisica, Università di Torino, via P. Giuria 1, Torino, 10125 Italy (Italy)

Radio-loud active galactic nuclei (AGN) are expected to contribute substantially to both the intensity and anisotropy of the isotropic γ-ray background (IGRB). In turn, the measured properties of the IGRB can be used to constrain the characteristics of proposed contributing source classes. We consider individual subclasses of radio-loud AGN, including low-, intermediate-, and high-synchrotron-peaked BL Lacertae objects, flat-spectrum radio quasars, and misaligned AGN. Using updated models of the γ-ray luminosity functions of these populations, we evaluate the energy-dependent contribution of each source class to the intensity and anisotropy of the IGRB. We find that collectively radio-loud AGN can account for the entirety of the IGRB intensity and anisotropy as measured by the Fermi Large Area Telescope (LAT). Misaligned AGN provide the bulk of the measured intensity but a negligible contribution to the anisotropy, while high-synchrotron-peaked BL Lacertae objects provide the dominant contribution to the anisotropy. In anticipation of upcoming measurements with the Fermi-LAT and the forthcoming Cherenkov Telescope Array, we predict the anisotropy in the broader energy range that will be accessible to future observations.

• OSTI ID: 22375750
• Journal Information: Journal of Cosmology and Astroparticle Physics, Journal Name: Journal of Cosmology and Astroparticle Physics Journal Issue: 11 Vol. 2014; ISSN 1475-7516
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ANISOTROPY
BL LACERTAE OBJECTS
ENERGY DEPENDENCE
ENERGY RANGE
FUNCTIONS
GALAXY NUCLEI
LUMINOSITY
PEAKS
QUASARS
SPECTRA
SYNCHROTRONS
TELESCOPES