### Abstract

We determine the effect of intergalactic magnetic fields on the distribution of high-energy gamma rays by performing three-dimensional Monte Carlo simulations of the development of gamma-ray-induced electromagnetic cascades in the magnetized intergalactic medium. We employ the so-called "Large Sphere Observer" method to efficiently simulate blazar gamma ray halos. We study magnetic fields with a Batchelor spectrum and with maximal left- and right-handed helicities. We also consider the case of sources whose jets are tilted with respect to the line of sight. We verify the formation of extended gamma ray halos around the source direction, and observe spiral-like patterns if the magnetic field is helical. We apply the Q-statistics to the simulated halos to extract their spiral nature and also propose an alternative method, the S-statistics. Both methods provide a quantitative way to infer the helicity of the intervening magnetic fields from the morphology of individual blazar halos for magnetic field strengths B10-15 G and magnetic coherence lengths Lc100 Mpc. We show that the S-statistics has a better performance than the Q-statistics when assessing magnetic helicity from the simulated halos.

Original language | English (US) |
---|---|

Article number | 083005 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 94 |

Issue number | 8 |

DOIs | |

State | Published - Oct 10 2016 |

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### ASJC Scopus subject areas

- Nuclear and High Energy Physics

### Cite this

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*94*(8), [083005]. https://doi.org/10.1103/PhysRevD.94.083005

**Probing intergalactic magnetic fields with simulations of electromagnetic cascades.** / Alves Batista, Rafael; Saveliev, Andrey; Sigl, Günter; Vachaspati, Tanmay.

Research output: Contribution to journal › Article

*Physical Review D - Particles, Fields, Gravitation and Cosmology*, vol. 94, no. 8, 083005. https://doi.org/10.1103/PhysRevD.94.083005

}

TY - JOUR

T1 - Probing intergalactic magnetic fields with simulations of electromagnetic cascades

AU - Alves Batista, Rafael

AU - Saveliev, Andrey

AU - Sigl, Günter

AU - Vachaspati, Tanmay

PY - 2016/10/10

Y1 - 2016/10/10

N2 - We determine the effect of intergalactic magnetic fields on the distribution of high-energy gamma rays by performing three-dimensional Monte Carlo simulations of the development of gamma-ray-induced electromagnetic cascades in the magnetized intergalactic medium. We employ the so-called "Large Sphere Observer" method to efficiently simulate blazar gamma ray halos. We study magnetic fields with a Batchelor spectrum and with maximal left- and right-handed helicities. We also consider the case of sources whose jets are tilted with respect to the line of sight. We verify the formation of extended gamma ray halos around the source direction, and observe spiral-like patterns if the magnetic field is helical. We apply the Q-statistics to the simulated halos to extract their spiral nature and also propose an alternative method, the S-statistics. Both methods provide a quantitative way to infer the helicity of the intervening magnetic fields from the morphology of individual blazar halos for magnetic field strengths B10-15 G and magnetic coherence lengths Lc100 Mpc. We show that the S-statistics has a better performance than the Q-statistics when assessing magnetic helicity from the simulated halos.

AB - We determine the effect of intergalactic magnetic fields on the distribution of high-energy gamma rays by performing three-dimensional Monte Carlo simulations of the development of gamma-ray-induced electromagnetic cascades in the magnetized intergalactic medium. We employ the so-called "Large Sphere Observer" method to efficiently simulate blazar gamma ray halos. We study magnetic fields with a Batchelor spectrum and with maximal left- and right-handed helicities. We also consider the case of sources whose jets are tilted with respect to the line of sight. We verify the formation of extended gamma ray halos around the source direction, and observe spiral-like patterns if the magnetic field is helical. We apply the Q-statistics to the simulated halos to extract their spiral nature and also propose an alternative method, the S-statistics. Both methods provide a quantitative way to infer the helicity of the intervening magnetic fields from the morphology of individual blazar halos for magnetic field strengths B10-15 G and magnetic coherence lengths Lc100 Mpc. We show that the S-statistics has a better performance than the Q-statistics when assessing magnetic helicity from the simulated halos.

UR - http://www.scopus.com/inward/record.url?scp=84992159629&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84992159629&partnerID=8YFLogxK

U2 - 10.1103/PhysRevD.94.083005

DO - 10.1103/PhysRevD.94.083005

M3 - Article

VL - 94

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 1550-7998

IS - 8

M1 - 083005

ER -