Parity-odd correlators of diffuse gamma rays and intergalactic magnetic fields

Abstract

We develop the connection between intergalactic helical magnetic fields and parity odd signatures in the diffuse gamma ray sky. We find that the location and the amplitude of a peak in a parity odd correlator, $Q(R)$, can be used to infer the normal and helical power spectra of the intergalactic magnetic field. When applied to Fermi-LAT data, the amplitude of the observed peak in $Q(R)$ gives $\sim 10^{-14}\mathrm{G}$ intergalactic magnetic field strength, which is consistent with an earlier independent estimate that only used the peak location (Tashiro et al. 2014). We discuss features in the observed $Q(R)$ that further support the intergalactic magnetic field hypothesis and make predictions for future tests.

10 pages, 4 figures

References in corpus (6)

• Lower limit on the strength and filling factor of extragalactic magnetic fields
• Adding helicity to inflationary magnetogenesis
• Gamma-ray induced cascades and magnetic fields in intergalactic medium
• A method of measurement of extragalactic magnetic fields by TeV gamma ray telescopes
• Helical Magnetic Fields from Sphaleron Decay and Baryogenesis
• Blazar halos as probe for extragalactic magnetic fields and maximal acceleration energy

Cited by in corpus (3)

• Gamma-ray observations of blazars and the intergalactic magnetic field spectrum
• Intergalactic magnetic field spectra from diffuse gamma rays
• Implications of a Primordial Magnetic Field for Magnetic Monopoles, Axions, and Dirac Neutrinos