Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
Polarized Synchrotron Emissivities and Absorptivities for Relativistic Thermal, Power-Law, and Kappa Distribution Functions
4 Pith papers cite this work. Polarity classification is still indexing.
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abstract
Synchrotron emission and absorption determine the observational appearance of many astronomical systems. In this paper, we describe a numerical scheme for calculating synchrotron emissivities and absorptivities in all four Stokes parameters for arbitrary gyrotropic electron distribution functions, building on earlier work by Leung, Gammie, and Noble. We use this technique to evaluate the emissivities and the absorptivities for a thermal (Maxwell-J\"uttner), isotropic power-law, and isotropic kappa distribution function. The latter contains a power-law tail at high particle energies that smoothly merges with a thermal core at low energies, as is characteristic of observed particle spectra in collisionless plasmas. We provide fitting formulae and error bounds on the fitting formulae for use in codes that solve the radiative transfer equation. The numerical method and the fitting formulae are implemented in a compact C library called ${\tt symphony}$. We find that: the kappa distribution has a source function that is indistinguishable from a thermal spectrum at low frequencies and transitions to the characteristic self-absorbed synchrotron spectrum, $\propto \nu^{5/2}$, at high frequency; the linear polarization fraction for a thermal spectrum is near unity at high frequency; and all distributions produce $O(10\%)$ circular polarization at low frequency for lines of sight sufficiently close to the magnetic field vector.
years
2026 4verdicts
UNVERDICTED 4representative citing papers
Simulations of accreting black holes in standard and complex spacetimes indicate that magnetic geometry, quantum corrections, and binary dynamics influence flares, precession, photon rings, and multi-wavelength variability, with potential EHT constraints.
GRRT simulations of spherically symmetric accretion show the Ellis-Bronnikov wormhole yields brighter shadow and photon ring than Schwarzschild, both consistent with EHT M87* data.
Review chapter summarizing the importance of small-scale galactic magnetic fields and proposing SKA observation strategies.
citing papers explorer
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Identifying Observational Signatures of Flux Eruption Events in Supermassive Black Hole Accretion Flows with Machine Learning
Machine learning on simulated images identifies that flux eruption events cause more diffuse, polarized, lower-flux millimeter emission with decreased Q-U loop rotation rate, achieving ~80% accuracy with random forests on summary statistics.
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GRMHD and GRRT Simulations of Black Hole Accretion: Flares, Precession, and Complex Spacetimes
Simulations of accreting black holes in standard and complex spacetimes indicate that magnetic geometry, quantum corrections, and binary dynamics influence flares, precession, photon rings, and multi-wavelength variability, with potential EHT constraints.
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Ellis-Bronnikov Wormhole Shadows with Spherically Symmetric Accretion Flow
GRRT simulations of spherically symmetric accretion show the Ellis-Bronnikov wormhole yields brighter shadow and photon ring than Schwarzschild, both consistent with EHT M87* data.
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Small-scale Magnetic Fields in the Milky Way and Nearby Galaxies
Review chapter summarizing the importance of small-scale galactic magnetic fields and proposing SKA observation strategies.