Limb-Brightened Jet in M87 from Anisotropic Nonthermal Electrons

Fuente: arXiv
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Autori principali: Tsunetoe, Yuh, Pesce, Dominic W., Narayan, Ramesh, Chael, Andrew, Gelles, Zachary, Gammie, Charles F., Quataert, Eliot, Palumbo, Daniel C. M.
Natura: Preprint
Pubblicazione: 2025
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author Tsunetoe, Yuh
Pesce, Dominic W.
Narayan, Ramesh
Chael, Andrew
Gelles, Zachary
Gammie, Charles F.
Quataert, Eliot
Palumbo, Daniel C. M.
author_facet Tsunetoe, Yuh
Pesce, Dominic W.
Narayan, Ramesh
Chael, Andrew
Gelles, Zachary
Gammie, Charles F.
Quataert, Eliot
Palumbo, Daniel C. M.
contents Very long baseline interferometry observations reveal that relativistic jets like the one in M87 have a limb-brightened, double-edged structure. Analytic and numerical models struggle to reproduce this limb-brightening. We propose a model in which we invoke anisotropy in the distribution function of synchrotron-emitting nonthermal electrons such that electron velocities are preferentially directed parallel to magnetic field lines, as suggested by recent particle-in-cell simulations of electron acceleration and the effects of synchrotron cooling. We assume that the energy injected into nonthermal electrons is proportional to the jet Poynting flux, and we account for synchrotron cooling via a broken power-law energy distribution. We implement our emission model in both general relativistic magnetohydrodynamic (GRMHD) simulations and axisymmetric force-free electrodynamic (GRFFE) jet models and produce simulated jet images at multiple scales and frequencies using polarized general relativistic radiative transfer. We find that the synchrotron emission is concentrated parallel to the local helical magnetic field and that this feature produces limb-brightened jet images on scales ranging from tens of microarcseconds to hundreds of milliarcseconds in M87. We present theoretical predictions for horizon-scale M87 jet images at 230 and 345 GHz that can be tested with next generation instruments. Due to the scale-invariance of the GRMHD and GRFFE models, our emission prescription can be applied to other targets and serve as a foundation for a unified description of limb-brightened synchrotron images of extragalactic jets.
format Preprint
id arxiv_https___arxiv_org_abs_2501_14862
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Limb-Brightened Jet in M87 from Anisotropic Nonthermal Electrons
Tsunetoe, Yuh
Pesce, Dominic W.
Narayan, Ramesh
Chael, Andrew
Gelles, Zachary
Gammie, Charles F.
Quataert, Eliot
Palumbo, Daniel C. M.
High Energy Astrophysical Phenomena
Astrophysics of Galaxies
Very long baseline interferometry observations reveal that relativistic jets like the one in M87 have a limb-brightened, double-edged structure. Analytic and numerical models struggle to reproduce this limb-brightening. We propose a model in which we invoke anisotropy in the distribution function of synchrotron-emitting nonthermal electrons such that electron velocities are preferentially directed parallel to magnetic field lines, as suggested by recent particle-in-cell simulations of electron acceleration and the effects of synchrotron cooling. We assume that the energy injected into nonthermal electrons is proportional to the jet Poynting flux, and we account for synchrotron cooling via a broken power-law energy distribution. We implement our emission model in both general relativistic magnetohydrodynamic (GRMHD) simulations and axisymmetric force-free electrodynamic (GRFFE) jet models and produce simulated jet images at multiple scales and frequencies using polarized general relativistic radiative transfer. We find that the synchrotron emission is concentrated parallel to the local helical magnetic field and that this feature produces limb-brightened jet images on scales ranging from tens of microarcseconds to hundreds of milliarcseconds in M87. We present theoretical predictions for horizon-scale M87 jet images at 230 and 345 GHz that can be tested with next generation instruments. Due to the scale-invariance of the GRMHD and GRFFE models, our emission prescription can be applied to other targets and serve as a foundation for a unified description of limb-brightened synchrotron images of extragalactic jets.
title Limb-Brightened Jet in M87 from Anisotropic Nonthermal Electrons
topic High Energy Astrophysical Phenomena
Astrophysics of Galaxies
url https://arxiv.org/abs/2501.14862