2024/10/09 by Rogemar A. Riffel, Riffel, Rogemar A., Gabriel Luan Souza-Oliveira +10 · 2 citations
Engineering · Physics and Astronomy · #Astronomical Observations and Instrumentation #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Gamma-ray bursts and supernovae
paper · pdf · doi:10.48550/arxiv.2410.06960
openalex publication_date 2024/10/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We use James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) medium-resolution spectrometer (MRS) observations of 3C 293 (UGC 8782), CGCG 012-070 and NGC 3884 to investigate the origin of the H2 emission. These three nearby Active Galactic Nucleus (AGN) hosts are known to present H2 emission excess relative to star-forming galaxies, as traced by the H2 S(3)/PAH\rm 11.3μm line ratio. We define the kinematically disturbed region (KDR) by the AGN and the virially dominated region (VDR) based on the H2 line widths, using the W\rm 80 parameter. From the correlations between W\rm 80 and H2 S(3)/PAH\rm 11.3μm, as well as the higher H2 S(5)/H2 S(3) and [Fe II]\rm 5.34 μm/PAH\rm 11.3μm ratios and flatter power-law temperature distributions observed in the KDR, we conclude that the H2 emission in the KDR is primarily driven by shock-heated gas. For 3C 293, the KDR is co-spatial with the radio core, indicating that the origin of the shocks is the interaction of the radio jet with the interstellar medium, which is also responsible for the observed molecular and ionized gas outflows in this source. The other galaxies are weak radio sources; however, due to the lack of high-resolution radio images, we cannot rule out low-power jets as the origin of the shock-heated H2. Our results indicate that the excess H2 emission excess is associated to shock heating of the gas, generated by outflows or by the interaction of the radio jet with the ambient gas.