Jet-driven shocks and turbulence in radio-loud Active Galactic Nuclei observed with JWST MIRI/MRS

Rogemar A. Riffel, Gabriel L. Souza-Oliveira, Luis Colina, Almudena Alonso-Herrero, Marina Bianchin, Kalliopi M. Dasyra, Lorenzo Evangelista, Kameron Goold, Pierre Guillard, Rogério Riffel, Anil Seth, Thaisa Storchi-Bergmann, Nadia Zakamska, Samile Araujo-Santos, Anelise Audibert, Enrica Bellocchi, Steph Campbell, Françoise Combes, Guilherme S. Couto, José Henrique Costa-Souza, Richard I. Davies, Maitê S. Z. de Mellos, Tanio Díaz-Santos, Fergus R. Donnan, Ismael García-Bernete, Santiago García-Burillo, Laura Hermosa Muñoz, Erin K. S. Hicks, Alvaro Labiano, Enrique Lopez-Rodriguez, Vincenzo Mainieri, Christopher Packham, Miguel Pereira Santaella, Cristina Ramos Almeida, Claudio Ricci, Lucas Ramos Vieira, Vivian U

First listed 2026-05-04 | Last updated 2026-05-04

Abstract

Jet-cloud interactions are a key manifestation of Active Galactic Nucleus (AGN) feedback on nuclear scales, distinct from the large-scale radio-mode feedback that suppresses gas cooling in galaxy halos. On these smaller scales, radio jets can inject energy and momentum into the interstellar medium (ISM), shaping the physical and kinematic properties of the nuclear and circumnuclear regions of galaxies. Using JWST MIRI/MRS observations of seven nearby radio-loud AGN (3C293, 3C305, Centaurus A, Cygnus A, IC5063, NGC1052, and M87), we investigate jet-driven turbulence in both the warm molecular and ionized gas phases. By combining spatially resolved H$_2$/PAH flux ratios with diagnostic line ratios of the ionized gas, we constrain the dominant H$_2$ excitation processes and assess the impact of radio jet--ISM interactions on the multiphase gas. We find that radio jets drive enhanced turbulence in both molecular and ionized (traced by [FeII], [NeII] and [NeIII] lines) gas, not only along but also perpendicular to the jet axis, indicating that jet--ISM interactions extend beyond the collimated jet channel and affect the nuclear environment. Strong correlations between the H$_2$/PAH ratio, the H$_2$ excitation temperature, and shock-sensitive ionized-gas tracers indicate that jet-driven shocks dominate the excitation of the H$_2$ rotational lines in most sources. These results indicate that radio jets are a key driver of multiphase ISM kinematics and excitation in nearby radio-loud galaxies.

Short digest

This paper uses JWST/MIRI MRS maps of seven nearby radio-loud AGN—3C 293, 3C 305, Centaurus A, Cygnus A, IC 5063, NGC 1052, and M87—to test how radio jets affect both warm molecular and ionized gas on circumnuclear scales. The core result is that elevated H2/PAH ratios, higher H2 excitation temperatures, and shock-sensitive ionized-gas tracers ([Fe II], [Ne II], [Ne III]) all track enhanced turbulence, with the effect seen not only along the jet axis but also in regions perpendicular to it. That combination argues that jet-driven shocks dominate the excitation of the H2 rotational lines in most of the sample, rather than a purely radiative origin. For LRDigest readers, the interesting takeaway is that even in nearby systems the jet couples to the multiphase ISM more broadly than a narrow collimated channel, offering a resolved template for how mechanical feedback can restructure black-hole fueling environments.

Key figures to inspect

• Figure 1 is the scene-setter: inspect how the MIRI/MRS spaxel measurements populate the H2 S(3)/PAH 11.3 versus PAH plane relative to the Spitzer SF, BAT AGN, and radio-selected AGN comparison samples, which shows whether these radio-loud nuclei are genuinely H2-enhanced at resolved scales rather than only in integrat…
• Figure 2 is the key diagnostic figure for the paper’s main claim. Compare the along-jet and perpendicular-to-jet spaxels in H2 S(3)/PAH versus H2 temperature, [Fe II]/PAH 11.3, and [Ne III]/[Ne II] to see whether shock-linked molecular excitation persists off-axis as well as within the radio channel.
• Figure 3 is worth checking after Figure 2 because it compresses the source-by-source correlation behavior. Use it to identify which galaxies show statistically significant coupling between H2 excess, molecular heating, and shock tracers, and which systems break the pattern or only show it in one orientation.
• Figure 4 is the best summary of the orientation test across the full sample. The paired along/perpendicular mean ratios, connected for each galaxy and color-coded by radio luminosity, let you judge whether the perpendicular enhancement is a subtle secondary effect or a systematic feature of powerful radio-loud AGN.
• If the full paper includes the sample/property table near Section 2, inspect it alongside Figures 2–4 to connect each galaxy’s distance and radio power to its line-ratio behavior; that helps separate truly generic jet-ISM coupling from source-specific geometry.