Future Perspectives on Black Hole Jet Mechanisms: Insights from Next-Generation Observatories and Theoretical Developments

TL;DR

The paper argues that a concerted effort combining horizon-scale imaging (EHT), high-energy gamma-ray observations (CTA), long-term optical monitoring (LSST), and coordinated multi-wavelength campaigns (WEBT) with advances in GRMHD and kinetic plasma simulations will transform our understanding of black hole jets. It proposes that next-generation observations, together with hybrid numerical methods and radiative transfer, can connect the physics at the event horizon to large-scale feedback in galaxies and clusters. Key contributions include outlining observational synergies, universal scaling relations, and the role of MADs and magnetic reconnection in jet launching and dissipation. The work highlights open questions and lays out concrete methodological pathways—computational advances, data science, and multi-messenger strategies—that will drive progress in jet physics and its cosmological impact.

Abstract

Black hole jets represent one of the most extreme manifestations of astrophysical processes, linking accretion physics, relativistic magnetohydrodynamics, and large-scale feedback in galaxies and clusters. Despite decades of observational and theoretical work, the mechanisms governing jet launching, collimation, and energy dissipation remain open questions. In this article, we discuss how upcoming facilities such as the Event Horizon Telescope (EHT), the Cherenkov Telescope Array (CTA), the Vera C. Rubin Observatory (LSST), and the Whole Earth Blazar Telescope (WEBT) will provide unprecedented constraints on jet dynamics, variability, and multi-wavelength signatures. Furthermore, we highlight theoretical challenges, including the role of magnetically arrested disks (MADs), plasma microphysics, and general relativistic magnetohydrodynamic (GRMHD) simulations in shaping our understanding of jet formation. By combining high-resolution imaging, time-domain surveys, and advanced simulations, the next decade promises transformative progress in unveiling the physics of black hole jets.

Figures (12)

• Figure S1: (Top) Observations from the Event Horizon Telescope of the supermassive black hole at the center of the elliptical galaxy M87, for four different days. (Bottom) Snapshots of the M87* black hole appearance, obtained from the EHT array of telescopes in 2009--2017. Where JCMT (James Clerk Maxwell Telescope), CARMA (Combined Array for Research in Millimeter-wave Astronomy), SMT (Heinrich Hertz Submillimeter Telescope), SMA (Submillimeter Array), CSO (Caltech Submillimeter Observatory), APEX (Atacama Pathfinder Experiment), LMT (Large Millimeter Telescope), IRAM (Institute for Radio Astronomy in the Millimetre Range) and SPT (South Pole Telescope). (EHT Collaboration (2019) 10.3847/2041-8213/ab0c96).
• Figure S2: (Top) EHT resolution (EHT collaboration 10.3847/2041-8213/ab0c96). (Bottom) Diagram of the EHT Network used for the observations in 2017. (Credit: Argonne National Laboratory-NRAO/AUI/NSF).
• Figure S3: Polarimetric imaging of M87* from 2017 April 11 low-band data. (Left) Total intensity images generated by EHT-imaging, polsolve, and LPCAL. EHT-imaging results are blurred to achieve
• Figure S4: CTA point source sensitivity comparison. (Top) Overall sensitivity of the full CTA array (black line, filled squares) against individual telescope types: 4 LSTs (red line, filled circles), 25 MSTs (green line, filled triangles), and 75 SSTs (blue line, upside-down triangles). Current instrument sensitivity for the same observation time is also shown (black line), with expected improvements as analysis algorithms evolve and the final layout is set. (Bottom) Differential flux sensitivity for the CTA southern array (black solid line) and northern array (blue dotted line). For context, sensitivities of H.E.S.S., VERITAS, MAGIC (for the same observation time), HAWC (one and five-year observations), and Fermi-LAT (10 years with two diffuse gamma-ray background levels) are included. (Credit: S. Mangano 10.48550/arXiv.1705.07805 and CTA collaboration-eoPortal https://www.eoportal.org/other-space-activities/cta).
• Figure S5: The LSST footprint, illustrating the sky observed over the 10-year survey and the distribution of on-sky visits across the major components of the LSST. Where N Visits (number of visits in the LSST footprint) (Credit: Schwamb et al. 2023 10.3847/1538-4365/acc173).