The course, which is a follow-up of the course Galaxy Evolution in Cosmic Structures A, is divided into two large modules. Both will explore the forward-modeling of state-of-the-art cosmological simulations, with the spirit that students can generalize these ideas and apply these same techniques to new problems in their own research, whether they work with galaxy images, spectra, or other data types.

Module 1: The 2D Observational Pipeline & Mock Galaxy Photometry: We will learn to handle simulation data and establish the "ground truth". Our primary case study will be a simulated galaxy. We will cover the full pipeline to create a realistic mock observation, including:

1. Stellar Population Synthesis (SPS) to convert particle mass to light.
2. Point Spread Function (PSF) convolution to simulate optical/atmospheric blurring.
3. Adding realistic sky background and instrumental noise.

Hands-on Goal: We will create, "observe," and analyze a mock galaxy image, to then carry out in a direct comparison of the "true" 3D mass profile with the "observed" 2D light profile.

Module 2: 1D Spectral Data, Redshift-Space. This module tackles 1D spectra. We will be the Lyman-alpha forest, which reveals the intergalactic medium (IGM). We will explore a different set of observational systematics, including

1. The physics of Ly-alpha optical depth.
2. The critical effect of Redshift-Space Distortions (RSDs).
3. Simulating a spectrograph's Line Spread Function (LSF).
4. The continuum fitting.

Hands-on Goal: We will generate a mock quasar spectrum from a simulation skewer and discover how the final "observed" Flux PDF is fundamentally different from the "true" underlying density field.

The course concludes with a final synthesis lecture on the universal principles of forward modeling and a discussion on what we can (and cannot) learn from numerical simulations.