Observables: Connecting Theory to Observations

The Observables module connects theoretical predictions to observational measurements.

This module handles the transformation from theoretical quantities to observable measurements, accounting for survey-specific effects.

Overview

This module computes survey-specific large scale structure (selection functions, window functions, and bias parameters) and galaxy cluster (halo mass function) quantities that distinguish real observations from idealized theoretical predictions.

This module addresses:

• Window functions for weak lensing surveys and CMB lensing
• Galaxy bias modeling and corrections
• Gravitational-wave source number counts and weak lensing
• Redshift-space power spectra P(k, μ)
• Halo mass function

Different Flavors of Observables

cloelib has different types of observable protocols, each serving different purposes for:

• Large Scale Structure
• Tracer Protocol: For photometric and gravitational-wave observables
  • Photometric tracers
  • Gravitational-wave tracers
• SpectroPower Protocol: For spectroscopic observables (3D clustering, redshift-space distortions).
• Galaxy Clusters
• HaloAbundance Protocol: For halo mass function and halo bias.

Next Steps

Ready to compute final statistics with your observables?

• Summary Statistics – Combine tracers into C_ℓ and multipoles
• Perturbations – Review structure formation
• Background – Review the foundation
• API Reference – Full technical details
• Back to Overview – Review the architecture