Courses Overview
Astrophysics deals with some of the most majestic themes known to science. Among these are the evolution of the universe from the Big Bang to the present day; the origin and evolution of planets, stars, galaxies, and the elements themselves; the unity of basic physical law; and the connection between the subatomic properties of nature and the observed macroscopic universe.

Contact Information
Assistant Chair for Academic Affairs: Richard Kron
Academic Affairs Administrator: Julia Brazas
Student Affairs Administrator: Laticia Rebeles

Undergraduate Courses
Several courses offered by the Department of Astronomy and Astrophysics satisfy the Core requirement in the Physical Sciences. Sequence descriptions may be found on the Physical Sciences page of the College Catalog.

PHSC 12600. Matter, Energy, Space, and Time
A comprehensive survey of how the physical world works, and how matter, energy, space, and time evolved from the beginning to the present. A brief survey of the historical development of mathematics, physics, and astronomy leads to a conceptual survey of the modern theory of the physical universe: space and time in relativity; the quantum theory of matter and energy; and the evolution of cosmic structure and composition. Systems such as black holes are used to illustrate the most extreme behaviors of nature, and systems such as stars are used to illustrate the explanatory power of physical reasoning. The major theme is understanding all of nature, from the prosaic to the exotic, using a powerful quantitative theory grounded in precise experiments.

PHSC 12600-99. Matter, Energy, Space, and Time (Paris)

PHSC 12610. Black Holes
The Universe is a laboratory that reveals the behavior of matter and radiation under intense pressure, temperature, and density, far more extreme than can be replicated on Earth. Depending on its mass, a star ends its life as a spinning white dwarf, neutron star, or black hole. The strength of gravity near these compact dead stars is so high that we can observe consequences of the bending of space-time. This course will provide the physical framework necessary to understand the origin and properties of some of the most powerful and exotic phenomena known, such as supernovae, gamma-ray bursts, and quasars.

PHSC 12610-99. Black Holes (Paris)

PHSC 12620. The Big Bang
The Big Bang model is a powerful framework for the interpretation of a wide range of observations and for making detailed and precise predictions for new experiments. The key motivating observations include the expansion of the Universe and how it has changed with time; the existence of radiation indicating a hot and dense early phase; the abundance of the light elements; and how matter is organized over a wide range of physical scales. The model naturally incorporates dark matter and dark energy, components that govern the growth of structure over time under the action of gravity. The course will explore the consequences of the model as it is applied to the earliest moments after the Big Bang, as well as to the fate of the Universe in the distant future.

PHSC 12620-99. The Big Bang (Paris)

PHSC 12700. Stars
Elements such as carbon and oxygen are created at high temperatures and pressures in the deep interiors of stars, conditions that naturally arise in stars like the Sun. This course will outline the physical principles at work: how the theory of stellar interiors accounts for how stars shine, why they live for such long times, and how the heavy elements in their cores are dispersed to form a new generation of stars. Gravity assembles stars out of more diffuse material, a process that includes the formation of planetary systems. The course shows how, taken together, these physical processes naturally lead to the ingredients necessary for the emergence of life, namely elements like carbon, nitrogen, and oxygen, and planets in stable orbits around long-lived stars.

PHSC 12700-99. Stars (Paris)
Offered in alternate years

PHSC 12710. Galaxies
Galaxies have been called "island universes," places where stars are concentrated, where they are born, and where they die. Galaxies are dynamic systems in the sense that they change with time and in the sense that gravity shapes the orbit of each star within its galaxy. The Sun is one star among the 100 billion in the Milky Way, each moving on an orbit that reflects the distribution of all the other stars. This course will trace the modern picture for the formation of galaxies and the stars in them. It will also review aggregates of galaxies, how galaxies move on orbits around each other at this higher level of the hierarchy of structure, and how we arrive at the conclusion that most of the matter in the Universe is in an exotic form (dark matter).

PHSC 12710-99. Galaxies (Paris)
Offered in alternate years

PHSC 12720. Exoplanets
The past two decades have witnessed the discovery of planets in orbit around other stars and the characterization of extra-Solar (exo-) planetary systems. We are now able to place our Solar System into the context of other worlds: A challenging next step is to find planets as small as the Earth in orbit around stars like the Sun. The architecture of planetary systems reflects the formation of the parent star and its protoplanetary disk, and how these have changed with time. This course will review the techniques for discovery of planets around other stars, what we have learned so far about exoplanetary systems, and the driving questions for the future, including the quest for habitable environments elsewhere.

PHSC 12720-99. Exoplanets (Paris)
Offered in alternate years

ASTR 13300. Introduction to Astrophysics
The course is intended for first-year students intending to major in Astrophysics as an introduction to the range of important physical processes that operate in astrophysical environments, and how these govern structures across a wide range of scales, from planets to superclusters. We will examine gravitating systems such as stars and galaxies, both in an out of equilibrium, in situations where the particles are collisionless (star clusters) and where the system is collisional (stars forming out of dense gas). The course will address thermal radiation in a number of contexts, including the relic radiation from the Big Bang. Line emission and absorption will also be introduced. Thermodynamic principles will be used to illuminate the behavior and evolution of a number of kinds of astrophysical systems, such as how supermassive black holes may have formed.

ASTR 18000. The Search for Extraterrestrial Life
Offered in alternate years
The origin of life is one of the biggest questions of modern science. While substantial progress has been made in understanding how life arose on our planet, such research represents just a single case study in how life originates and evolves. This course covers the search for life beyond Earth from the planets and moons of the Solar System to planets orbiting other stars and intelligent life that may have left its mark on macroscopic scales. The discovery of life beyond Earth would be transformative for our understanding of humanity's place in the universe. A range of ongoing and planned experiments have the potential to detect or put strong constraints on the existence of life during the next few decades. This class will mix traditional lectures with flipped classroom problem solving sessions.

ASTR 18100. The Milky Way
Within a largely empty universe, we live in a vast stellar island that we call the Milky Way. As we survey the stellar and interstellar components of the Milky Way, the distribution and motions of stars and interstellar gas, and how these dynamic, ever-changing components interact with each other during their life cycles inside the Milky Way, we will follow the path of ancient astronomers, wonder at their mistakes and prejudices, and form our own understanding.

ASTR 18200. The Origin and Evolution of the Universe
Offered in alternate years
This course discusses how the laws of nature allow us to understand the origin, evolution, and large-scale structure of the universe. After a review of the history of cosmology, we see how discoveries in the twentieth century (i.e., the expansion of the universe and the cosmic background radiation) form the basis of the hot Big Bang model. Within the context of the Big Bang, we learn how our universe evolved from the primeval fireball.

ASTR 18300. Searching Between the Stars
Offered in alternate years
With the advent of modern observational techniques such as radio and satellite astronomy, it has become possible to study free atoms, molecules, and dust in the vast space between the stars. The observation of interstellar matter provides information on the physical and chemical conditions of space and on the formation and evolution of stars.

ASTR 18400. Origins: From the Big Bang to Human Consciousness
Offered in alternate years
In this course we will look at the approaches to, data for, and theories of the big transitions in the evolution of the physical universe and the living world.

ASTR 18700. Fossils to the Fermi Paradox
The course approaches Fermi's question, "Are we alone in the universe?," in the light of recent evidence primarily from three fields: the history and evolution of life on Earth (paleontology), the meaning and evolution of complex signaling and intelligence (cognitive science), and the distribution, composition and conditions on planets and exoplanets (astronomy). We also review the history and parameters governing extrasolar detection and signaling. The aim of the course is to assess the interplay between convergence and contingency in evolution, the selective advantage of intelligence, and the existence and nature of life elsewhere in the universe, in order to better understand the meaning of human existence.

ASTR 18800. Philosophical Problems in Cosmology
Offered in alternate years
In this course, we will undertake a comparison of the philosophical underpinnings of the Aristotelian and Copernican cosmologies, including a comparison of mechanistic and teleological approaches to the natural world. The epistemological foundations of the scientific method, in particular as applied to cosmology (from Galileo to the modern context) will be examined, as will positivist vs. realistic outlooks on cosmology. (For example, what does science say-or not say-about the inside of a black hole, or the space beyond the Hubble horizon?) We will ponder questions such as: Do the epistemological foundations of science require us to be able to repeat relevant experiments? If so, does this disqualify cosmology as a science? If not, why? Might our universe be part of a computer simulation? What information could possibly convince us that this is true or false?

ASTR 20000. Tutorial in Astronomy and Astrophysics
Students in this tutorial read topics in astronomy and astrophysics under the supervision of a faculty member. Students meet with the instructor in groups of one to three for approximately two hours per week to discuss readings on mutually agreed-upon topics.

ASTR 21100. Computational Techniques in Astrophysics
This course will introduce basic computational techniques most often used in astronomical research, such as interpolation, transforms, smoothing, numerical differentiation and integration, integration of ordinary differential equations, and Monte Carlo methods, and elements of basic computer algorithms, data structures, and parallel programming using Python as the main course programming language. Practical examples where these numerical techniques are applied will be covered via homework and in class exercises using real-world astronomical problems and results of recent papers with emphasis on implementing the algorithms from scratch. The course will cover the access to astronomical archival data, and how to search it efficiently, focusing specifically on the Sloan Digital Sky Survey, but with introduction to other data sets. Machine learning methods will be introduced to illustrate how large data sets can be mined for interesting information.

ASTR 21200. Observational Techniques in Astrophysics
This course will prepare students in methods that will be used in their independent research by introducing observation and analysis techniques in a field of astrophysics chosen by the instructor. Students will learn basics of astronomical instrumentation and will apply that knowledge in a practical context (for example, using an on-campus telescope or telescopes controlled robotically from campus). The process of data reduction and calibration will be illustrated, leading to the extraction of scientifically meaningful results.

ASTR 23900. Physics of Galaxies
This course will provide a comprehensive introduction to the formation and evolution of galaxies, review key components such as stars, gas, dust, and dark matter, and examine the physical processes involved in their structure and evolution. The discussion will start with the Milky Way as an example and transition to the general properties of nearby galaxies and beyond. Topics will include the stellar content of galaxies and the dynamics of stars within galaxies, the physical state of the interstellar medium, central supermassive black holes, clusters of galaxies, gravitational lensing, and processes that shape the relative distributions of dark matter and baryonic matter.

ASTR 24100. The Physics of Stars
Building upon a student's previous knowledge of physics, this course introduces the astrophysics of stars and stellar systems with an emphasis on the physical nature of stars. Topics include the tools of astronomy, both observational and theoretical Hertzsprung-Russell diagrams, structure and evolution of stars, binary stars, star clusters, and end states of stars such as white dwarfs, neutron stars, and black holes.

ASTR 24300. Cosmological Physics
This course will provide a comprehensive introduction to the principal topics in cosmology, including theoretical and observational foundations. Key topics will include the expansion of the Universe, dark matter and energy, cosmic microwave background, hot Big Bang, and the origin and evolution of structure.

ASTR 25400/30500. Radiation Processes
Most of what we know about the Universe comes from detection of electromagnetic radiation emitted by individual sources or by diffuse media. Once we understand the processes by which the radiation was created and the processes by which the radiation is scattered or modified as it passes through matter, we can address the physical nature of the sources. The physics of radiation processes includes electricity and magnetism; quantum mechanics and atomic and nuclear structure; statistical mechanics; and special relativity.

ASTR 25800. Extrasolar Planets
Offered in alternate years
Extrasolar planets, a.k.a. exoplanets, are planets orbiting other stars. First definitively detected in the mid 1990s, the planet count has rapidly expanded and their physical characterization has sharpened with improved observational techniques. Theoretical studies of planetary formation and evolution are now attempting to understand this statistical sample. The field also aspires to address questions about life in the universe. This course emphasizes hands-on activities, like working with real astronomical data to find and characterize exoplanets. Topics are the radial velocity, transit, and other discovery and characterization techniques; statistical distributions of known planets; comparisons among planet structure and planetary system types; formation in a protoplanetary disk and subsequent dynamical evolution; the goal of finding life on an exoplanet; colonization of exoplanets; and the Fermi paradox.

ASTR 28300. Current Topics: Instrumentation
The topic of this course in 2019 is Catching Long-wavelength Photons. Many important events in the history of our universe are best observed at wavelengths between the microwave and the far-infrared. These include the cosmic microwave background (CMB), the early galaxies which played host to the first stars during the epoch of reionization, and the astrophysical processes which drive nearby star forming regions. This class will introduce these science topics and then explore in detail the tools and techniques required to measure this radiation. Topics will include: antennas, horns, and direct absorbers; receiver sensitivity and fundamental noise sources; coherent detectors, bolometers, and pair-breaking superconducting devices; microwave theory and interferometry; telescope fundamentals; and a survey of current and near-future instruments. This course should provide a comprehensive background for students interested in instrumentation for the CMB, submm, and far-IR astronomy. Grading will include problem sets and a final project in which students design their own detailed instrument proposal. There are no lab sections, though some class sessions will involve hands-on demonstrations in a research lab on campus.

ASTR 28500/41200. Science with Large Astronomical Surveys
The last several years have seen a veritable explosion of novel astronomical survey programs covering large areas of sky with unprecedented sensitivity. This course will explore the wide variety of science that can be done with surveys like the Sloan Digital Sky Survey, the Dark Energy Survey, the Gaia satellite, and the upcoming Large Synoptic Survey Telescope. Science topics will include our solar system, our Galaxy, the Local Group, distant galaxies, and cosmological measurements of our Universe. We will familiarize ourselves with the hardware and software components of astronomical surveys, before diving into hands-on analysis of public data sets. Students will learn computational and statistical techniques for analyzing large astronomical data sets.

ASTR 29700. Participation In Research: Astronomy and Astrophysics
Students are assigned to work in the research group of a member of the faculty. Participation in research may take the form of independent work on a small project or assistance to an advanced graduate student or faculty member in his or her research.

ASTR 29800. Undergraduate Research Seminar
In this course students will engage with various scientific practices to prepare them for participation in research. Students will critically analyze research presented in popular and scholarly scientific literature and practice computational, statistical, and observational techniques to explore astrophysical problems. The course will emphasize student-led discussions and interactive presentations to synthesize previous coursework and strengthen scientific thinking and communication skills. Guest lectures by members of research groups will highlight projects undertaken by faculty in the Astronomy and Astrophysics Department to acquaint students with possibilities for research participation.

Core Graduate Courses

ASTR 30100. Stars
Introduction to stars (physical and observational), hydrodynamics of self-gravitating fluids, statistical mechanics and equations of state, energy transport, astrophysical nuclear reactions, stellar models, advanced topics.

ASTR 30300. Interstellar Matter
This course will cover a range of physical processes that govern the thermal and dynamical states of interstellar gas in molecular, atomic, and ionized phases. It will explore different spectral features and line diagnostics for gas density, ionization state, temperature, chemical compositions, and dust content.

ASTR 30400. Galaxies
The observed universe, the universe at high redshift, early universe microwave background radiation, relativistic homogeneous isotropic cosmologies, evolution of structure in the universe, primordial nucleosynthesis.

ASTR 30600. Radiation Measurements in Astrophysics
Radiation as a random process, optical coherence, and signal analysis in spatial and temporal domains, along with the detection and measurement of radiation with astronomical instruments.

ASTR 31000. Cosmology I
Large scale structure of the universe, expansion, composition, epochs, measurements.

ASTR 49900. Graduate Research Seminar
The instructor chooses a topic for the seminar and assigns papers that develop the topic from the earliest times to the most recent results. Students each present papers during the course, as assigned, and lead a discussion. The purpose is to give students practice in analyzing the literature and in presenting to their peers, as well to assure breadth in the topics covered during their time at Chicago. The class meets once per week for one hour.

Elective Graduate Courses
Courses numbered 40000 - 48000 are lecture or seminar courses taught from time to time in specialized or advanced topics in fields in which members of the department are working. Admission to any of these is by permission of the instructor. Typical courses include:

ASTR 31100. High Energy Astrophysics
This course covers a wide range of phenomena associated with the astrophysics of high energy photons, cosmic rays and neutrinos, including the processes of ionization, bremsstrahlung, synchrotron, pion production, Compton and inverse Compton scattering, as well as cosmic ray acceleration. Specific sources of high energy emission will also be discussed, including active galaxies, pulsars, gamma-ray bursts and supernova remnants.

ASTR 33000. Computational Physics and Astrophysics
Basic computational methods useful for astrophysics, supplemented by specific examples drawn primarily from astrophysics. Starting with basics (e.g., precision, errors and error analysis) and basic computational methods (differentiation, integration/quadrature, Monte Carlo, numerical linear algebra), and then discussing solution of problems posed in terms of ordinary and partial differential equations.

ASTR 34000. Statistical Methods in Astronomy and Astrophysics
An exploration of the variety of statistical methods used in modern astrophysics. We discuss the frequentist (hypothesis tests, confidence intervals) and Bayesian (explicit priors, model-choosing, parameter estimation) approaches. Other topics include: Markov Chain Monte Carlo and other computational statistics; multi-dimensional likelihood space; Fischer information matrices; time series analysis. Assignments draw from examples in the astronomical literature.

ASTR 35800. Extrasolar Planets
Extrasolar planets, a.k.a. exoplanets, are planets orbiting other stars. First definitively detected in the mid 1990s, the planet count has rapidly expanded and their physical characterization has sharpened with improved observational techniques. Theoretical studies of planetary formation and evolution are now attempting to understand this statistical sample. The field also aspires to address questions about life in the universe. This course emphasizes hands-on activities, like working with real astronomical data to find and characterize exoplanets. Topics are the radial velocity, transit, and other discovery and characterization techniques; statistical distributions of known planets; comparisons among planet structure and planetary system types; formation in a protoplanetary disk and subsequent dynamical evolution; the goal of finding life on an exoplanet; colonization of exoplanets and the Fermi paradox.

ASTR 37100. Pre-Candidacy Research
Supervised research of students normally in their first two years of graduate study.

ASTR 40100. Practical Data Analysis
Offered in alternate years
This course will touch on basic issues related to analyzing and interpreting astronomical data. An emphasis will be placed on understanding the limitations and biases in different types of observations and measurements, and on finding ways of addressing and quantifying them. The course will be project driven so that the students will gain hands-on experience working with different types of data. The projects will cover a range of topics that involve imaging and spectral analysis, and explorations of public data archives.

ASTR 40800. The Perturbed Universe
Offered in alternate years
This seminar course will cover inflation as the source of structure in the universe and its observational signatures. Topics will include relativistic perturbation theory, canonical and general single field inflationary models, primordial non-Gaussianity, and gravitational waves.

ASTR 40900. Topics in Observational Cosmology
Offered in alternate years
Specialized problems in the field, depending on current forefront areas and interest of the instructor.

ASTR 41100. Science of the Dark Energy
Offered in alternate years
Is the accelerated expansion of the Universe due to dark energy or does it require a modification of gravity? This informal seminar course will focus on the use of the Dark Energy Survey (DES), and by extension other surveys, to probe the origin of cosmic acceleration. The course will cover the techniques for probing dark energy in detail, with particular emphasis on weak and strong lensing, clusters, large-scale structure, cross-correlations with the CMB, and supernovae, and explore how DES will realize these techniques. We will familiarize ourselves with the main hardware and software components of the project that underlie the data and science it produces. Students will be given access to proprietary DES data and learn basic techniques for querying the database and looking at the data; and will formulate projects involving analysis of the data, depending on their interests and level of expertise, and report on their findings later in the quarter. By the end of the course, those interested in participating in the DES should have the basic tools to jump into the project (or other projects) and take part in science analysis, and those already involved will hopefully have their skills and knowledge enhanced. The course will start with lectures reviewing cosmic acceleration and the techniques for probing dark energy, continue with more specialized talks and discussions on various aspects of the Dark Energy Survey project and science, including discussion of early DES science papers, and finish with student presentations on DES data exploration and analysis.

ASTR 44800. Cosmic Microwave Background
Offered in alternate years
The first half of the course will be lectures with the goal of establishing a common denominator, and the second half will be research. The course requires a final project to be presented in class. Prerequisites are graduate-level cosmology and general relativity.

ASTR 45800. Exoplanets
Offered in alternate years
The study of exoplanets, planets associated with stars other than the Sun, has become one of the most exciting and rapidly evolving areas of modern astronomy. This new course will address general questions concerning the detection and characterization of exoplanets and of what we have already learned about the origin and properties of exoplanetary systems and of how they compare with those of the Solar System. This discussion will be placed in the context of models of planet formation in protoplanetary disks, their structure and composition, and their dynamical interactions with the natal disk, the parent star, and other planets. The course will make use of seminal papers on these topics and will encourage active participation by the students.

ASTR 45900. What Make a Planet Habitable?
*Dorian Abbot, Fred Ciesla (cross-listed as GEOS 32060).*

This course explores the factors that determine how habitable planets form and evolve. We will discuss a range of topics, from the formation of planets around stars and the delivery of water, to the formation of atmospheres, climate dynamics, and the conditions that allow for the development of life and the evolution of complex life. Students will be responsible for reading and discussing papers in peer-reviewed journals each meeting and for periodically preparing presentations and leading the discussion.

ASTR 46100. Dynamics of Exoplanets
Offered in alternate years
Exoplanets are planets that orbit other stars. As most detection methods are indirect, planets' orbital dynamics is key to basic characterization, and it was historically important to confirm their existence. Their surprising orbital properties challenged planet formation and evolution theories, prompting further development of dynamical theories. This course covers orbital mechanics of N-body systems from the short-term, relevant to observations such as transit-timing variations, all the way to billion-year timescales, relevant to the dynamical winnowing of unstable systems. It covers highly eccentric and inclined orbits, scattering and resonant dynamics, planetary orbits in binary star systems, the additional physics of tidal dissipation and orbital migration due to a gas disk, and current research topics.

ASTR 48000. Current Topics in Astrophysics
Offered in alternate years
This course explores in considerable detail an area of current faculty research interest in astrophysics. The topic varies, but recent examples include the early universe, high-energy astrophysics, magneto-hydrodynamics in astrophysics, and observational cosmology.