Course information
ASTR 476: Observational Cosmology · 3 credits · Year 4 elective · 14 weeks.
Description: Observational foundations of modern cosmology, including redshift and distance measures, Type Ia supernovae, baryon acoustic oscillations, CMB acoustic physics, weak lensing, structure growth, parameter inference, survey selection, and systematic uncertainty.
Prerequisites: ASTR 420 or concurrent enrollment, consistent with the curriculum catalog.
Planning assumption: two 75-minute meetings per week; each numbered item is a weekly lecture module taught across those meetings. Confirm institutional policies, instructor details, dates, accessibility, and local prerequisites before use.
Learning outcomes
- Derive and compute cosmological redshift, FLRW distances, and distance-modulus relations with assumptions and units.
- Explain how SNe Ia, BAO, CMB anisotropies, weak lensing, and clustering constrain different combinations of cosmological parameters.
- Use covariance-aware likelihood calculations and distinguish measurement, derived quantity, and model-dependent inference.
- Assess calibration, selection, nuisance parameters, and model assumptions in a published cosmological result.
- Build reproducible analyses with source provenance, pinned software, numerical checks, and explicit limitations.
- Communicate a claim whose strength matches the data and likelihood actually available.
Schedule
| Week | Lecture module | Work due |
|---|---|---|
| 1 | Lecture 01: Redshift, Scale Factor, and the Expanding Universe | Lecture and reading preparation |
| 2 | Lecture 02: The FLRW Distance Ladder | Lab 01; Problem Set 01 |
| 3 | Lecture 03: Type Ia Supernovae as Standardizable Candles | Lecture and reading preparation |
| 4 | Lecture 04: Supernova Covariance and Calibration | Lab 02; Problem Set 02 |
| 5 | Lecture 05: Baryon Acoustic Oscillations as a Standard Ruler | Lecture and reading preparation |
| 6 | Lecture 06: The CMB Acoustic Scale | Lab 03; Problem Set 03 |
| 7 | Lecture 07: Weak Gravitational Lensing and Cosmic Shear | Lecture and reading preparation |
| 8 | Lecture 08: Growth of Structure and Redshift-Space Distortions | Lab 04; Problem Set 04 |
| 9 | Lecture 09: Likelihoods, Priors, and Parameter Degeneracies | Lecture and reading preparation |
| 10 | Lecture 10: Survey Selection and Malmquist Bias | Lab 05; Problem Set 05 |
| 11 | Lecture 11: Cross-Probe Concordance and Tension | Lecture and reading preparation |
| 12 | Lecture 12: Curvature and Evolving Dark Energy | Lab 06; Problem Set 06 |
| 13 | Lecture 13: Systematics, Calibration, and Error Budgets | Lecture and reading preparation |
| 14 | Lecture 14: Observational Cosmology Synthesis | Lab 07; Problem Set 07 |
Assessment
| Component | Weight | Evidence |
|---|---|---|
| Seven data/computational labs | 35% | Runnable methods, uncertainty, validation, source audit |
| Seven problem sets | 35% | Derivations, calculations, interpretation, covariance reasoning |
| Final evidence dossier | 20% | Reproducible claim-to-evidence chain with peer audit |
| Participation and research critique | 10% | Structured discussion of assumptions and alternative explanations |
| Total | 100% |
Cadence and resources
Fourteen weekly lecture modules are paired into seven two-week units. One lab and one problem set cover each pair and are due at the end of the second week (Weeks 2, 4, 6, 8, 10, 12, and 14). This deliberate 14/7/7 cadence gives time for data work and uncertainty analysis; it is not a one-to-one lecture-to-assessment schedule. See schedule.html for the exact map.
CPython 3.14.6; pinned NumPy, SciPy, Astropy, and Matplotlib versions are listed in requirements.txt. No paid account or observatory access is assumed. The Pantheon+ excerpt is live-verified, redshift-stratified, and unsuitable for survey-level inference. Other data are published summaries or model illustrations as labeled in reference-log.md.
Students may discuss concepts, but submitted reasoning and analysis must be attributable. Cite data, software, and adapted code. Revisions and resubmissions are encouraged to improve mastery; high standards for method, evidence, uncertainty, and interpretation remain in force.