PHY 524 - Graduate Cosmology


Welcome to the home page for the course “Cosmology” (PHY 524) in Spring 2022.

Overview of Course: This course covers the standard model of cosmology, including both the homogeneous Universe and perturbation theory, and the main observational tests of this model. 

Lecturer:            Neelima Sehgal

Contact:             neelima.sehgal{at}

Class Times:     Tuesdays and Thursdays   1:15pm - 2:35pm  in person in Psychology A 146



Office Hours:    Fridays 9:30 - 10:30am  in ESS 454

Grader:    Rugved Pund (rugved.pund{at}

Grader Office Hours:    Thursday 9:30 - 10:30am  in ESS 431

Course grade:   Homework Problem Sets (25%)

                            Take Home Midterm (35%)

                            Take Home Final Exam (40%)

                            Homeworks and Exams are to be submitted electronically via Blackboard

                            Attendance Mandatory (with covid exceptions)

Course Text Book: Modern Cosmology by Scott Dodelson and Fabian Schmidt, Academic Press, 2021

Other Useful Text Books: Cosmology by Steven Weinberg, Oxford University Press, 2008

                                            Introduction to the Theory of the Early Universe

                                                        by D. Gorbunov and V. Rubakov, World Scientific, 2011

                                            Introduction to Cosmology by Barbara Ryden, Addison Wesley, 2003

                                            (the last book is an undergrad text and may provide useful review)  

Prerequisites: Knowledge of standard undergraduate physics (classical mechanics, electrodynamics, quantum mechanics, and thermodynamics) is assumed.  Some knowledge of general relativity is also assumed (e.g. read Dodelson pages 23 - 33 prior to the start of class).  No prior knowledge of quantum field theory, astronomy, or cosmology is assumed.

Topics to be Covered:

Homogeneous Universe:

•    Friedmann-Robertson-Walker metric and Friedmann equations

•    Expansion history and distance measures

•    Standard candles and standard rulers

•    Relativistic degrees of freedom and the neutrino background

•    Big-Bang nucleosynthesis

•    Recombination

Perturbation theory:

•    Perturbed metric and Boltzmann equation for photons in real space

•    Boltzmann equation for photons in Fourier-multipole space 

•    Perturbation equations for neutrinos, dark matter, and baryons

•    Einstein equations and gauge transformations

•    Initial conditions and adiabatic vs. isocurvature modes 

•    Inflation

•    Generation of perturbations in inflation

•    Inhomogeneities and the matter power spectrum

•    CMB power spectrum

•    CMB polarization

Student Accessibility Support Center Statement:

If you have a physical, psychological, medical, or learning disability that may impact your course work, please contact the Student Accessibility Support Center, 128 ECC Building, (631) 632-6748, or at They will determine with you what accommodations are necessary and appropriate. All information and documentation is confidential.

Academic Integrity Statement:

Each student must pursue his or her academic goals honestly and be personally accountable for all submitted work. Representing another person's work as your own is always wrong. Faculty is required to report any suspected instances of academic dishonesty to the Academic Judiciary. Faculty in the Health Sciences Center (School of Health Technology & Management, Nursing, Social Welfare, Dental Medicine) and School of Medicine are required to follow their school-specific procedures. For more comprehensive information on academic integrity, including categories of academic dishonesty please refer to the academic judiciary website at

Critical Incident Management:

Stony Brook University expects students to respect the rights, privileges, and property of other people. Faculty are required to report to the Office of University Community Standards any disruptive behavior that interrupts their ability to teach, compromises the safety of the learning environment, or inhibits students' ability to learn. Faculty in the HSC Schools and the School of Medicine are required to follow their school-specific procedures. Further information about most academic matters can be found in the Undergraduate Bulletin, the Undergraduate Class Schedule, and the Faculty-Employee Handbook.