The Meudon PDR code is one of the community codes of INSU. It is one of the few astrochemical codes that solves, in a coupled and self-consistent way, radiative transfer, gas-phase and grain-surface chemistry, thermal balance including individual heating and cooling mechanisms, and statistical equilibrium, out of thermodynamic equilibrium, in the quantum states of the main species of an interstellar cloud exposed to stellar radiation. The code determines the spatial profiles of the abundances of hundreds of chemical species, the thermal structure of the gas and grain populations, and the intensities of thousands of resulting atomic and molecular lines from the ultraviolet to the radio domain.
The Meudon PDR code has been developed and continuously improved for more than 20 years. It is used by the community to interpret observations from all types of instruments observing from the UV to the radio (FUSE, HST, VLT instruments, ISO, Spitzer, Herschel, JWST, IRAM, NOEMA, ALMA, …) or to prepare new observing campaigns, or even prepare future missions. It is versatile enough to have been used for various problems : diffuse clouds, photodissociation regions (PDRs), proplyds, circumstellar disks, debris disks, Galactic and extragalactic star-forming regions, low-metallicity galaxy gas, damped Lyman-alpha systems at high redshift, …
The service consists in maintaining a stable version of the code and expanding its physics and capabilities according to user needs, helping users run the code and helping developers improve it, coordinating the developer community, optimizing the code for current architectures, and ensuring its portability across different machines.
