Impact of disk magnetic fields on the propagation of stellar-scale jets in the magnetically arrested accretion disks of active galactic nuclei

It is widely recognized that active galactic nucleus (AGN) disks host numerous massive stars and compact objects. Stellar-scale jets triggered by collapses of massive stars and mergers of compact objects could propagate through the disk and produce observable electromagnetic radiation. Magnetically arrested disks (MADs), supported by both numerical simulations and observations, possess strong magnetic fields (MFs). As jets travel within such environments, the MFs should regulate jet evolution and shape radiation signatures. In this work, we explore the effects of disk MFs on jet propagation and breakout emission within the MAD framework. We employ a jet-cocoon model that accounts for potential disk-MF effects, including both magnetic pressure and magnetic energy dissipation driven by magnetic reconnection. We find that magnetic pressure effectively suppresses the lateral expansion of the cocoon, which enhances jet collimation and modestly increases the jet-head velocity. Furthermore, magnetic pressure effects are more pronounced at relatively low jet powers. In this regime, the breakout luminosity of the jet-head shock is enhanced, while its breakout time is shortened. However, the magnitude of the luminosity enhancement is sensitive to the adopted regime-dependent emission prescriptions. These findings suggest that, within the explored parameter space, disk MFs can facilitate the breakout of low-power jets arising from binary black hole mergers in AGN MADs.

Improvements to AI Systems:

1. Physics-constrained jet propagation model: Integrate the paper’s jet-cocoon framework (including magnetic pressure and magnetic reconnection energy dissipation) into AI-based astrophysical simulators, enabling accurate prediction of jet-head velocity, cocoon lateral expansion, and breakout time under magnetically arrested disk (MAD) conditions.

2. Regime-aware emission synthesis: Enhance AI models for electromagnetic counterpart prediction by incorporating the paper’s finding that breakout luminosity enhancement depends on regime-dependent emission prescriptions—allowing AI to dynamically switch between radiative efficiency models based on jet power and magnetic field strength.

3. Parameter-space optimization for low-power jet detectability: Use the paper’s result that magnetic pressure boosts low-power jet breakout to train AI classifiers that identify binary black hole merger events in AGN MADs with higher detection probability, optimizing telescope follow-up scheduling.

4. Causal inference for magnetic field effects: Improve AI interpretability tools to isolate the specific contribution of magnetic pressure vs. magnetic dissipation on jet collimation, using the paper’s parametric dependencies (e.g., stronger effect at lower jet powers) as testable constraints for model validation.

5. Surrogate modeling for multi-messenger astrophysics: Train a neural network surrogate on the paper’s jet-cocoon equations to rapidly map input parameters (jet power, disk magnetic field strength, ambient density) to breakout luminosity and time, enabling real-time Bayesian inference for upcoming gravitational-wave+electromagnetic observations.

What the improved AI system can do:

• Predict whether a given AGN disk jet will break out and its observable flux, with accuracy matching the paper’s analytical model but at 1000× lower computational cost.

• Automatically adjust emission models based on the local magnetic environment, avoiding false negatives for low-luminosity jet counterparts.

• Rank candidate electromagnetic counterparts from LIGO/Virgo triggers in AGN MADs, prioritizing those with enhanced breakout due to magnetic pressure.

• Provide physically interpretable uncertainty estimates, distinguishing between magnetic-pressure-driven and reconnection-driven luminosity enhancements.

It is widely recognized that active galactic nucleus (AGN) disks host numerous massive stars and compact objects. Stellar-scale jets triggered by collapses of massive stars and mergers of compact objects could propagate through the disk and produce observable electromagnetic radiation. Magnetically arrested disks (MADs), supported by both numerical simulations and observations, possess strong magnetic fields (MFs). As jets travel within such environments, the MFs should regulate jet evolution and shape radiation signatures. In this work, we explore the effects of disk MFs on jet propagation and breakout emission within the MAD framework. We employ a jet-cocoon model that accounts for potential disk-MF effects, including both magnetic pressure and magnetic energy dissipation driven by magnetic reconnection. We find that magnetic pressure effectively suppresses the lateral expansion of the cocoon, which enhances jet collimation and modestly increases the jet-head velocity. Furthermore, magnetic pressure effects are more pronounced at relatively low jet powers. In this regime, the breakout luminosity of the jet-head shock is enhanced, while its breakout time is shortened. However, the magnitude of the luminosity enhancement is sensitive to the adopted regime-dependent emission prescriptions. These findings suggest that, within the explored parameter space, disk MFs can facilitate the breakout of low-power jets arising from binary black hole mergers in AGN MADs.