# ASTR 420 Reference Log

## Adopted textbook and embedded-figure checks

- OpenStax, *Astronomy 2e*, Chapter 29, “The Big Bang,” sections 29.1-29.7. The extracted text at `references/openstax-astronomy-2e-extracted.txt` contains the native chapter heading and embedded captions including Figures 29.10 and 29.11. The generated source index places some chapter labels one block earlier near the Chapter 29 boundary; therefore the native embedded figure numbers and adopted PDF must control final assignment wording.
- OpenStax Chapter 26, section 26.5, “The Expanding Universe,” supports distance ladders, redshift, and supernova context. Chapter 28, sections 28.4-28.5, supports lensing and large-scale structure. All chapter/figure claims require a human adopted-PDF spot-check before instructional use.
- Exact exercise anchors used in the problem sets: Chapter 29 Review Questions 1, 3, 10, and 12; Figuring for Yourself 29, 30, 31, and 32 as available in the extracted index. Because the generated exercise index has boundary offsets, these identifiers are flagged for direct PDF verification rather than treated as authoritative numbering.

## Data provenance levels

- **Level 1, live-verified this session:** local OpenStax extracted text and source-index files were directly inspected in this workspace. This verifies the chapter/figure text presence, not the adopted edition's final exercise pagination.
- **Level 2, published/literature values not re-verified this session:** Planck-style CMB summaries (H0=67.4, Omega_m=0.315, Omega_b=0.0493, T_CMB=2.7255 K), standard BAO summary ratios, compact supernova distance-modulus teaching values, primordial abundance summaries, and representative matter-power values. Human spot-check against Planck 2018, DESI/BAO releases, Pantheon+/SH0ES or an instructor-selected SN compilation, and BBN review literature is required.
- **Level 3, synthetic/instructor-provided:** the compact CSV teaching extracts are reduced, rounded instructional tables assembled from the level-2 summaries; SVG diagrams, perturbation tests, and the stated model curves are generated illustrations, not observations.

## Additional references requiring human spot-check

- Planck Collaboration VI (2020), *A&A* 641, A6, DOI 10.1051/0004-6361/201833910.
- Riess et al. (2022), *ApJL* 934, L7, DOI 10.3847/2041-8213/ac5c5b.
- Eisenstein et al. (2005), *ApJ* 633, 560, DOI 10.1086/466512.
- Abbott et al. (2018), *ApJ* 858, 19, DOI 10.3847/1538-4357/aabdec.
- Cyburt et al. (2016), *Rev. Mod. Phys.* 88, 015004, DOI 10.1103/RevModPhys.88.015004.

No external images are embedded. The lecture figures are original SVG diagrams generated by `src/generate_astr420_package.py`; they are schematic/model figures and are labeled as such in captions.