In the realm of energy journalism, a recent study has shed light on the intricate dynamics of active galaxies, with potential implications for our understanding of energy processes in the universe. The research team, led by Dr. C. Marconcini from the University of Florence, Italy, and including members from various institutions across Europe, utilized the James Webb Space Telescope (JWST) to observe the active galaxy NGC 1068. Their findings were published in the journal Astronomy & Astrophysics.
The team combined Mid-Infrared (Mid-IR) and optical Integral Field Spectroscopy (IFS) data from the JWST’s Mid-Infrared Instrument (MIRI) and the Multi Unit Spectroscopic Explorer (MUSE) to examine the multi-phase circumnuclear gas properties in NGC 1068. This active galaxy is known for its powerful Active Galactic Nucleus (AGN), which drives an outflow of gas and a radio jet. The researchers aimed to understand the interaction between this outflow and the surrounding gas.
The MIRI data provided a resolution of 20-60 parsecs and traced the multiphase gas emission up to 400 parsecs from the nucleus. This revealed a clumpy ionized structure around the radio hotspots and a rotating warm molecular disc. The researchers developed innovative Mid-IR diagnostic diagrams that highlighted the AGN as the main excitation source for the ionized gas in the entire MIRI field of view. This finding supports the scenario where the AGN drives a wind that interacts with the surrounding gas.
Density-sensitive Mid-IR transitions of [NeV] and [ArV] revealed high-density clumps along the edges of the jet and outflow, indicating gas compression by the expanding wind. The team combined multi-cloud kinematic modeling (MOKA) and photo-ionization modeling (HOMERUN) to characterize the ionized outflow properties. They found that the [OIV] line traces an outflow that is 300 km/s faster than that inferred from the [OIII] line, suggesting that these lines originate from distinct gas components.
The photoionization analysis required a dust-poor component dominating the optical lines and a dust-rich component responsible for the Mid-IR emission. The Mid-IR-revealed dusty component carries a significantly larger ionized-gas mass than what can be inferred from optical lines alone, showing that most of the outflowing mass is hidden from classical optical diagnostics. The researchers proposed a two-stage acceleration scenario, with velocities up to ~2000 km/s, consistent with an energy-driven wind.
The findings indicate that the outflow entrains up to a few million solar masses of ionized gas and couples efficiently with the surrounding interstellar medium (ISM), injecting turbulence and impacting the host-galaxy environment. This research provides a deeper understanding of the energy processes in active galaxies and the role of AGN outflows in shaping their surroundings.
While the direct practical applications for the energy sector may not be immediately apparent, understanding the fundamental processes governing energy dynamics in the universe can inspire innovative approaches to energy generation, storage, and transmission. The insights gained from studying AGN outflows and their interaction with the ISM can potentially inform the development of advanced energy technologies that harness similar principles.
This article is based on research available at arXiv.