ASTR 420 PS 05 Solutions: Structure Growth and BAO

Rubric

Problems 1-4 are 25 points each. Require dimensional consistency, correct comparative direction, explicit assumptions, reproducibility, and interpretation. Accept equivalent derivations when the physical meaning is preserved.

Problem 1

Solution route: define the measured quantity, write the model, substitute shared values, and test the stated assumption.

Key check: Linear matter-era growth from z=1100 to today is a factor of 1+z = 1101; a 10^-5 seed becomes 0.01101 in the idealized model.

Problem 2

Solution route: define the measured quantity, write the model, substitute shared values, and test the stated assumption.

Key check: The analysis must contain a labeled data display, uncertainty or sensitivity treatment, and a provenance statement; an unsupported scalar answer is incomplete.

Problem 3

Solution route: define the measured quantity, write the model, substitute shared values, and test the stated assumption.

Key check: The analysis must contain a labeled data display, uncertainty or sensitivity treatment, and a provenance statement; an unsupported scalar answer is incomplete.

Problem 4

Solution route: define the measured quantity, write the model, substitute shared values, and test the stated assumption.

Key check: The analysis must contain a labeled data display, uncertainty or sensitivity treatment, and a provenance statement; an unsupported scalar answer is incomplete.

Common errors

using cz as a universal cosmological velocity;
mixing Mpc, km, and seconds without conversion;
reversing a ratio or calling a model-dependent quantity direct;
ignoring covariance, selection, or the approximation domain.