Reconstructing parametric gravitational-wave population fits from non-parametric results without refitting the data

Understand

Combining multiple events into population analyses is a cornerstone of gravitational-wave astronomy.

• A critical component of such studies is the assumed population model, which can range from astrophysically motivated functional forms to non-parametric treatments that are flexible but difficult to interpret.
• In practice, the current approach is to fit the data multiple times with different population models to identify robust features.
• We propose an alternative strategy: assuming the data have already been fit with a flexible model, we present a practical recipe to reconstruct the population distribution of a different model.