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Galaxies and Cosmology

An introduction to the modern extragalactic astronomy and cosmology, the physical universe, big bang, formation and evolution of galaxies, quasars, and large-scale structure.


Course at a Glance


About the Course

This class is an introduction to the modern extragalactic astronomy and cosmology, i.e., the part of astrophysics that deals with the structure and evolution of the universe as a whole, and its major constituents: dark matter, dark energy, galaxies, quasars, large-scale structure, and intergalactic gas.  It will cover the subjects including: relativistic cosmological models and their parameters, extragalactic distance scale, cosmological tests, composition of the universe, dark matter, and dark energy; the hot big bang, cosmic nucleosynthesis, recombination, and cosmic microwave background; formation and evolution of structure in the universe; galaxy clusters, large-scale structure and its evolution; galaxies, their properties and fundamental correlations; formation and evolution of galaxies; star formation history of the universe; quasars and other active galactic nuclei, and their evolution; structure and evolution of the intergalactic medium; diffuse extragalactic backgrounds; the first stars, galaxies, and the reionization era.  It corresponds to the Ay 21 class taught at Caltech.

Course Syllabus

Galaxies and Cosmology

The lecture schedule and topics covered by this class are given below. There is no midterm or final for this class, but there are graded quizzes at the end of each week based on lecture material.

Week 1 

Chapter 1: Introduction

  • Cosmology as a science
  • An overview of the modern cosmology and its history
  • Units, fluxes, and magnitudes

Chapter 2: Basics of Relativistic Cosmology

  • Basic concepts of General Relativity
  • Symmetry assumptions: homogeneity and isotropy
  • Metric, Robertson-Walker
  • The cosmological redshift
  • Comoving and proper coordinates
  • Friedmann equation
  • Definitions of cosmological parameters

Week 2 

Chapter 3: Cosmological Models

  • Computing cosmological models
  • Distances in cosmology
  • Basics of cosmological tests
  • The cosmic horizons

Chapter 4: Distance Scale, Age of the Universe, and the Universal Expansion

  • Distance scale and the Hubble constant
  • The age of the universe
  • Tests of the universal expansion

Week 3

Chapter 5: Cosmological Tests

  • Classical cosmological tests and their problems
  • Modern tests (non-CMBR)
  • Tests using CMBR fluctuations

Chapter 6: The hot Big Bang and the Thermal History of the Universe

  • Planck era and beyond
  • Inflation
  • Baryosynthesis
  • Nucleosynthesis
  • Recombination
  • Reionization

Week 4 

Chapter 7: Contents of the Universe

  • Luminous matter, M/L ratios
  • Baryons
  • Dark matters
  • Gravitational lensing
  • Dark energy, cosmological constant and quintessence

Chapter 8: Structure Formation: Theory

  • Density fluctuations, power spectrum, growth, damping
  • Dark matter dependence of cosmogony; Cold Dark Matter
  • Post-recombination growth
  • Collapse of density fluctuations
  • The role of cooling; galaxies vs. clusters and LSS
  • Numerical simulations
  • Galaxy merging

Week 5 

Chapter 9: Observations of Large Scale Structure

  • Measurements of galaxy clustering and LSS
  • Redshift surveys

Chapter 10: Large Scale Structure and Clusters of Galaxies

  • Peculiar motions
  • Evolution of clustering
  • Biasing
  • Galaxy clusters and their properties

Week 6 

Chapter 11: Galaxies, Their Structure and Properties (I)

  • Galaxy catalogs, morphological classification, Hubble sequence
  • Variation of galaxy properties along the Hubble Sequence
  • Stellar populations and galaxian subsystems
  • Galaxy luminosity and mass functions
  • Properties of spiral galaxies, density wave theory

Chapter 12: Galaxies, Their Structure and Properties (II)

  • Properties of elliptical galaxies
  • Supermassive black holes in nearby galaxies
  • Properties of dwarf galaxy families
  • Fundamental correlations, scaling relations, and their uses

Week 7 

Chapter 13: Galaxy Evolution

  • Basic processes of galaxy evolution: merging, stellar pop. modeling
  • Deep surveys (imaging and redshift)
  • Selection effects and obscured star formation
  • Star formation history, assembly of the mass
  • The Olbers paradox
  • Optical/NIR and FIR/sub-mm diffuse backgrounds

Chapter 14: Chemical Evolution, Intergalactic Medium and its Evolution

  • Chemical evolution of galaxies
  • Basic phenomenology of absorbers
  • LyA forest, Lyman limit systems, Damped LyA systems
  • Evolution of IGM and its chemical enrichment
  • Feedback processes and the cosmic web

Week 8 

Chapter 15: Galaxy Formation

  • Basics of galaxy formation
  • The first galaxies and early stages of galaxy evolution
  • Reionization era
  • The first stars
  • The origins of black holes in the early universe

Chapter 16: Quasars and Active Galactic Nuclei: Phenomenology and Physics

  • AGN properties, basics, classification, spectra
  • Supermassive black holes and their fueling
  • Emission mechanisms
  • AGN unification

Week 9 

Chapter 17: Quasars and AGN: Unification, Evolution, High-Energy Backgrounds

  • Jets and beaming
  • Quasar surveys and evolution
  • X-ray, gamma-ray, and AGN-generated backgrounds
  • The origin of first quasars and supermassive black holes

Recommended Background

This class assumes at a minimum a prior knowledge of astronomy at a good mid-undergraduate level (e.g., “Astro 101” for science majors, not “Astro 1” for poets), knowledge of physics at a comparable level, and math at a level of calculus or higher.  A substantive Wikipedia article is about at the right level.

Suggested Readings

The class, including the supplementary readings to be posted on the appropriate Chapter pages, is designed to be self-contained.  However, the following books would be useful for students desiring to acquire a deeper and more substantive knowledge of the subject:

Extragalactic Astronomy and Cosmology: An Introduction , by P. Schneider, Springer, ISBN-13: 978-3642069710
Introduction to Cosmology by B. Ryden. Addison Wesley, ISBN-13: 978-0805389128
Cosmology: The Science of the Universe by E. Harrison, Cambridge U. Press, ISBN-13: 978-0521661485

These are also illustrative of the anticipated level of the class.

Course Format

The class will consist of lecture videos, typically ~ 10 minutes in length, grouped in Chapters, 2 per week.  Mini-quizzes will be embedded in these video modules.  There will be a quiz at the end of each week.  On-line materials will be provided on the class website.  There will be various discussion venues (discussion threads on the Coursera site, FB page, virtual office hours).


  • What resources will I need for this class?

    Internet access. Some math package (e.g., Matlab, Mathematica) may be helpful. The books recommended above would be also very useful.

  • What is the coolest thing I'll learn if I take this class?

    How the universe evolves, and how do we get to know that.