Questions CosmicGrain Is Built to Answer
Where does a galaxy's dust mass actually come from?
Stellar sources alone struggle to produce the dust masses observed in galaxies within the time available — implying substantial in-situ growth in the ISM. CosmicGrain tracks the full production, growth, and destruction cycle self-consistently, letting us ask directly where that missing dust mass comes from.
How do dust-to-gas and dust-to-metal ratios evolve with environment?
Because CosmicGrain resolves individual grain populations rather than a single galaxy-wide average, D/G and D/Z can be measured locally — in the ISM, in outflows, in the halo — rather than assumed.
Does dust survive the journey into the circumgalactic medium?
This is a question about dust kinematics, not just chemistry — exactly what an explicit-particle approach is suited to answer.
How does grain size respond to different ISM environments?
Shocks, turbulence, and dense molecular gas each push grain size distributions in different directions. CosmicGrain tracks each superparticle's radius individually, making it possible to see exactly how and where the distribution shifts — and why.
What Makes the Approach Different
Most cosmological dust models treat dust as an attribute of the surrounding gas — a scalar quantity that moves wherever the gas moves. CosmicGrain instead evolves dust as explicit N-body superparticles, each with its own position, velocity, grain size, and composition, fully coupled to gravity, aerodynamic drag, and radiation pressure the same way GADGET-4 already integrates dark matter and stellar particles.
The practical consequence: CosmicGrain can directly resolve where dust decouples from gas — in fast-moving outflows, in the diffuse circumgalactic medium, near young, radiatively active stars — rather than assuming dust always moves with the flow it was born in. That decoupling is often exactly the thing under investigation, not a detail to average away.