Lunch talk on Dec. 8, 2025

Understanding Photodissociation Regions in Galactic and Extragalactic Environments

Speaker: Thomas Bisbas (Zhejiang Lab.)

Venue: SWIFAR Building 2111

Time: 12:45 PM, Monday, Dec. 8, 2025

Abstract: 

Photodissociation regions (PDRs) are the sites where the atomic-to-molecular transition occurs, as well as the transition between the three phases of carbon (C+, C and CO) known as the "carbon cycle". The abundances and the emission of the carbon cycle are highly sensitive to the interstellar medium (ISM) environmental conditions, such as the cosmic-ray ionization rate, the FUV intensity and the gas-phase metallicity. In this talk, I will present insights from three-dimensional numerical modeling and comparisons with observational data, demonstrating how PDRs—and the carbon cycle in particular—serve as powerful probes of environmental properties in both galactic and extragalactic ISM. I will also present recent high-resolution PDR models generated using the upgraded 3D-PDR code, highlighting its enhanced capabilities.