A new interpretation of the gamma-ray observations of distant active galactic nuclei

By Warren Essey, A. Kusenko. 2009

148 citations recorded by the source corpus.

Abstract Gamma-ray telescopes have reported some surprising observations of multi-TeV photons from distant active galactic nuclei (AGN), which show no significant attenuation due to pair production on either the extragalactic background light (EBL), or the photons near the source. We suggest a new interpretation of these observations, which is consistent with both the EBL calculations and the AGN models. Cosmic rays with energies below 50 EeV, produced by AGN, can cross cosmological distances, interact with EBL relatively close to Earth, and generate the secondary photons observed by γ -ray telescopes. We calculate the spectrum of the secondary photons and find that it agrees with the γ -ray data. The delays in the proton arrival times can explain the orphan flares, the lack of time correlations, and the mismatch of the variability time scales inferred from the multiwavelength observations. The γ -ray data are consistent with the detection of the secondary photons, which has important ramifications for gamma-ray astronomy, cosmic ray physics, EBL, and the intergalactic magnetic fields (IGMF).

Subfields: Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/0cbf21ea098a7c1125dbf0710b195c47b100349c

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Nuclear and High Energy Physics

Citations in the corpus

THE EXTRAGALACTIC BACKGROUND LIGHT, THE HUBBLE CONSTANT, AND ANOMALIES: CONCLUSIONS FROM 20 YEARS OF TeV GAMMA-RAY OBSERVATIONS (2015, background): “…the fact that EBL reconstructed from gamma-ray observations follows the expected spectrum are pieces of evidence against scenarios in which the VHE emission of blazars would primarily come from ultra-highenergy cosmic rays (UHECR) reprocessed along the line of sight (e.g., Essey & Kusenko 2010).”
EVIDENCE FOR GAMMA-RAY HALOS AROUND ACTIVE GALACTIC NUCLEI AND THE FIRST MEASUREMENT OF INTERGALACTIC MAGNETIC FIELDS (2010, unknown): “Finally, at TeV energies, the secondary photons produced in interactions of cosmic rays with EBL may have already been observed by the air Cherenkov telescopes (Essey & Kusenko 2010; Essey et al. 2010).”
Open Questions in Cosmic-Ray Research at Ultrahigh Energies (2019, unknown): “The signature of UHECR acceleration could be detectable in the gamma-ray spectra of blazars ( Gabici and Aharonian, 2005; Essey and Kusenko, 2010; Essey et al., 2010; Kotera et al., 2011; Murase et al., 2012; Prosekin et al., 2012; Aharonian et al., 2013; Takami et al., 2013; Oikonomou et al.,…”
2FHL: THE SECOND CATALOG OF HARD FERMI-LAT SOURCES (2015, background): “These photons are especially interesting for testing alternative photon-propagation scenarios such as secondary cascades (Essey & Kusenko 2010) and axion-like particles (e.g.,de Angelis et al. 2007; SánchezConde et al. 2009; Domínguez et al. 2011a; Horns & Meyer 2012).”
THE COSMIC CORE-COLLAPSE SUPERNOVA RATE DOES NOT MATCH THE MASSIVE-STAR FORMATION RATE (2011, background): “If secondary gamma rays produced en route by beamed cosmic rays are important (Essey & Kusenko 2010; Essey et al. 2011), the EBL could be even higher.”
Indications for a pair-production anomaly from the propagation of VHE gamma-rays (2012, background): “[3, 4] for gamma-ray induced cascades and [5–7] for ultra-high energy proton induced cascades)1.”
ROLE OF LINE-OF-SIGHT COSMIC-RAY INTERACTIONS IN FORMING THE SPECTRA OF DISTANT BLAZARS IN TeV GAMMA RAYS AND HIGH-ENERGY NEUTRINOS (2010, background): “…1966; Zatsepin & Kuzmin 1966) is much larger than the horizon size, the protons do rarely interact with the background photons and produce secondary gamma rays at a rate that results in observable flux and shows an excellent agreement with the data (Essey & Kusenko 2010; Essey et al. 2010b).”
3FHL: The Third Catalog of Hard Fermi-LAT Sources (2017, background): “These photons permit testing EBL models and evaluating potential changes in the optical depth due to other more exotic scenarios (e.g., de Angelis et al. 2007; Sánchez-Conde et al. 2009; Essey & Kusenko 2010; Domínguez et al. 2011b; Horns & Meyer 2012).”
A hadronic origin for ultra-high-frequency-peaked BL Lac objects (2014, background): “…from the emitting region trigger intergalactic cascades with the extragalactic background light (EBL) or cosmic microwave background (CMB) (e.g. Essey & Kusenko 2010; Dermer et al. 2012; Murase et al. 2012) Proton-proton interactions (important in denser environments, such as supernovae…”
BLAZARS AS ULTRA-HIGH-ENERGY COSMIC-RAY SOURCES: IMPLICATIONS FOR TeV GAMMA-RAY OBSERVATIONS (2011, background): “The curve labeled “E14, low IR" is the spectrum resulting from the cascade of Emax = 1014 eV photons withβ = 5/4 produced at the source for the low-IR EBL model.”