High-energy neutrinos and gamma rays from winds and tori in active galactic nuclei

分类： 天文学 >> 天文学 提交时间： 2023-02-19

Susumu Inoue Matteo Cerruti Kohta Murase Ruo-Yu Liu

摘要： Powerful winds with wide opening angles, likely driven by accretion disks around black holes (BHs), are observed in the majority of active galactic nuclei (AGN) and can play a crucial role in AGN and galaxy evolution. If protons are accelerated in the wind near the BH via diffusive shock acceleration, $p\gamma$ processes with AGN photons generate neutrinos as well as pair cascade emission from the gamma-ray to radio bands. The TeV neutrinos detected by IceCube from the obscured Seyfert galaxy NGC 1068 can be interpreted consistently if the shock velocity is appreciably lower than the local escape velocity, which may correspond to a failed, line-driven wind that is physically well motivated. Although the $p\gamma$-induced cascade is $\gamma\gamma$-attenuated above a few MeV, it can still contribute significantly to the sub-GeV gamma rays observed from NGC 1068. At higher energies, gamma rays can arise via $pp$ processes from a shock where an outgoing wind impacts the obscuring torus, along with some observable radio emission. Tests and implications of this model are discussed. Neutrinos and gamma rays may offer unique probes of AGN wind launching sites, particularly for objects obscured in other forms of radiation.

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