Year: 2026
Type: preprint
Abstract: Upcoming advances in high-frequency VLBI promise to enable spatially resolved studies of astrophysical jets across an increasingly large source population. We present here a Python implementation of the semi-analytic model from Tsunetoe et al. (2025) for self-consistently interpreting the spatial and spectral structure of the synchrotron emission from such jets. The model is based on an axisymmetric force-free jet solution supplemented with a prescription for nonthermal electron heating, synchrotron cooling, pitch-angle anisotropy in the electron distribution, and radiative transfer along straight rays. We use this model to explore how the predicted spectral energy distribution depends on the model parameters, identifying approximately self-similar scalings with black hole mass, accretion rate, and electron heating efficiency. We also compare the model predictions against observations of M87 and Sgr A*. For M87, a single fiducial parameter set qualitatively reproduces VLBI images across multiple frequencies and matches the observed longitudinal intensity profile, while also yielding a broadband SED that is quantitatively consistent with the observed radio through X-ray measurements. For Sgr A*, a fit to the quiescent-state SED demonstrates that emission from a collimated jet with comparable nonthermal heating efficiency to M87's is quantitatively consistent with the observed radio through X-ray measurements, predicting a compact jet whose radio size decreases inversely with frequency, consistent with VLBI constraints.
Source: arXiv (Cornell University)
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, National Aeronautics and Space Administration, John Templeton Foundation, Gordon and Betty Moore Foundation, California Institute of Technology, Harvard University, National Natural Science Foundation of China, Chinese Academy of Sciences, Shanghai Branch, Japan Society for the Promotion of Science
Awards: G1125352646, G159909979, The Black Hole Initiative, G3901735354, G4006987460, G4248050400, Sharpening the View of Black Holes, G4759703258, The Black Hole Initiative: Towards a Center for Interdisciplinary Research, G5037849455, Enabling the Next-Generation Event Horizon Telescope: Towards Movies of Black Holes, G5507044963, G5586996422, Mid-scale RI-1 (M1:DP): Next Generation Event Horizon Telescope Design, 硫黄細菌の生化学的研究, G6925086031, G7276985768, G757325902, The Event Horizon Telescope: Resolving Black Holes in Time and Space, G7854666520, Black Hole Initiative Phase 3, Frontier Science with the Event Horizon Telescope, 基于超高分辨率观测的近邻超大质量黑洞研究
OpenAlex ID: W7222423309