Axion-Like particles from extragalactic High Energy sources

14th International Conference on Topics in Astroparticle and Underground Physics

物理学;天文学

Conrad, J.^1 ; Meyer, M.^1 ; Montanino, D.^2

Oskar Klein Center for Cosmo Particle Physics, Department of Physics, Stockholm University, Albanova, Stockholm

SE-10691, Sweden^1

Dipartimento di Matematica e Fisica Ennio de Giorgi, Università Del Salento, Sezione INFN di Lecce, Via Arnesano, Lecce

I-73100, Italy^2

关键词: Cherenkov telescope arrays;    Cosmic microwave backgrounds;    Extragalactic background light;    Extragalactic sources;    Galactic magnetic fields;    Imaging air Cherenkov telescopes;    Magnetic field parameter;    Turbulent magnetic fields;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/718/5/052026/pdf
DOI  :  10.1088/1742-6596/718/5/052026

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

Background radiation fields (such as Extragalactic Background Light, EBL, or Cosmic Microwave Background, CMB) pervade the Universe. Above a certain energy any gamma ray flux emitted by an extragalactic source should be attenuated by the process γ+ γ(bgk)→ e++ e-pair production. We have considered a scenario in which the photons are partly converted into light Axion Like Particles (ALPs) in the local magnetic field of an (extragalactic) source. Then, while the unconverted fraction of photons undergo absorption, the ALP component travel to our galaxy where is converted back to photons by the galactic magnetic field resulting in a sort of cosmic light shining through wall effect. In particular, we have considered two scenarios: 1) conversion in the turbulent magnetic field inside a galaxy cluster; and 2) conversion of photons in the coherent magnetic field at parsec scales in a Blazar jet. Afterwards, we have also analyzed mock data coming from a hypothetical Imaging Air Cherenkov Telescopes (IACT) array with characteristics similar to the Cherenkov Telescope Array (CTA) and we have investigated the dependence of the sensitivity to detect a gamma ray excess on the magnetic field parameters.