Molecular conversion of the simulated cold phase

Ascertain the fraction of the simulated cold gas phase (T < 10^4 K) in AGN-driven outflows that transitions to molecular gas under realistic ISM cooling and chemistry, in order to quantify mass budgets and compare with observations of molecular outflows.

Background

The simulations include only primordial cooling, producing a cold phase down to T ≈ 104 K, and therefore provide conservative lower estimates for cold-phase mass outflow rates. Observationally, molecular (e.g., CO-traced) outflows often dominate mass budgets, so knowing how much of the simulated cold gas becomes molecular is essential for comparison.

Including metal-line and low-temperature cooling, molecular chemistry, and radiative transfer may alter the phase structure and increase the mass in the molecular component; the authors call out the need to quantify this conversion explicitly.

References

In particular, how much of our 'cold phase' eventually turns molecular remains to be understood.

— AGN-driven outflows in clumpy media: multiphase structure and scaling relations (2407.17593 - Ward et al., 24 Jul 2024) in Conclusions and Outlook (Section 6)