Description
It is well-established that shocks are the key driver for dust destruction in the interstellar medium (ISM). Feedback process from active galactic nuclei (AGN), such as winds and jets, can generate shocks that create harsh conditions where dust is expected to be destroyed.
Surprisingly, recent JWST observations show that dust grains and polycyclic aromatic hydrocarbons (PAHs) can persist in extreme environments (eg, high temperatures, fast winds) that favour grain destruction through sputtering and/or shattering. The processes underlying dust survival and processing in shocks remain poorly understood. In this talk, I will report on JWST/MIRI imaging of extended dust structures aligned with the narrow line region of a number of nearby AGN, where shocks are prevalent. Using simple models, I will demonstrate that not only does dust co-exists with shocks, but is also likely heated by them. To explore this further, I will present results from hydrodynamical simulations run with the Arepo code, to investigate dust survival under thermal sputtering in AGN-driven shocks. These simulations show that conditions such as grain size, shock velocity, gas temperature, and cooling efficiency can significantly influence the sputtering timescale. This has important implications for AGN feedback efficiency and the dust lifecycle, both of which are key to galaxy evolution.
