Projects

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Galaxy-in-a-box

Galaxy-in-a-Box is a model that predicts galactic-scale emission from active star formation based on the properties of protostellar outflows. In its current form, it focuses on the water line emission at 987.9 GHz (H₂O 2₀₂–1₁₁) and examines whether this line can trace star-forming activity across cosmic environments. However, the framework could be applied to any molecule for which there is solid observational evidence linking its emission to protostellar outflows and a substantial number of observational data points.

The ultimate goal is to connect the emission from outflows, which are one of the key signposts of active star formation, with what we observe on larger scales, where molecular feedback can capture more than just star formation. Ideally, we could identify a clean molecular diagnostic of star formation that remains reliable across different environments. This perspective allows us to ask questions such as:

• To what extent does the emission traced by a given molecular line actually originate from ongoing star formation?
• Can this emission be used to quantify the level of star-formation activity in different environments?
• Is it possible to disentangle the contribution of star-formation-driven outflows from other sources within the same line emission?

So far, Galaxy-in-a-Box (and so the WED framework) has shown that the total H₂O emission is primarily governed by the star-formation efficiency and the adopted free-fall-time scaling, with only a minor dependence on the IMF and molecular-cloud mass function (Dutkowska & Kristensen 2022, A&A 667, A135). A subsequent study linked water-line and far-infrared luminosities to star-formation rates and demonstrated that additional physical processes are required to reproduce the brightest systems (Dutkowska & Kristensen 2023, A&A 674, A95).

While independent from WED, the project benefits from the same empirical foundation by testing how the statistical behaviour of water emission observed in protostellar environments translates to integrated galactic scales. Code and documentation are available on GitHub.