2004/09/15 by Jian-Min Wang, Jian‐Min Wang · 2 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Astrophysics and Cosmic Phenomena #Compton scattering #Electron #Galaxies: Formation, Evolution, Phenomena #Galaxy #Infrared #Lorentz factor #Lorentz transformation #Nuclear physics #Photon #Physics #Quantum mechanics #Spitzer Space Telescope #Telescope #Torus #astro-ph
paper · pdf · doi:10.1086/425318
published as Astrophys.J. 614 (2004) L21-L24 · 4 pages in emulateapj5.sty; 1 figure
openalex publication_date 2004/09/15 · arxiv created 2004/12/03 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
A geometrically thick dusty torus in NGC 1068 has been unambiguously resolved by an infrared interferometry telescope. This implies that clouds composing the dusty torus are undergoing supersonic collisions with each other. We show that the collisions form strong nonrelativistic shocks, which accelerate populations of relativistic electrons. The torus reprocesses emission from the accretion disk into an infrared band. We show that the energy density of the infrared photons inside the torus is much higher than that of the magnetic field in the clouds, and the seed photons of inverse Compton scattering are mainly from the infrared. The maximum energy of the relativistic electrons can reach a Lorentz factor of 10 5 . We calculate the spectrum of the synchrotron and inverse Compton scattering radiation from the electrons in the torus. The relativistic electrons in the torus radiate nonthermal emission from radio to γ-ray, which isotropically diffuses in the region of the torus. We find that the most prominent character is a peak at ~0.5-1 GeV. We apply this model to NGC 1068 and find that the observed radio emission from the core component S 1 can be explained by the synchrotron emission from the relativistic electrons. We predict that there is γ-ray emission with a luminosity of 10 40 ergs s -1 peaking at ~1 GeV from the torus, which could be detected by the Gamma-Ray Large-Array Space Telescope in the future. This will provide a new clue to understanding the physics in the torus. The nonthermal radiation from the dusty torus may explain the radio emission from Seyfert galaxies. The cosmological implications of the nonthermal emission to the γ-ray background radiation are also discussed.