ASTR 5770 Fall 2025 Syllabus

ASTR 5770 Fall 2025 Homepage

ASTR 5770 Cosmology Fall 2025: Syllabus

Content

Cosmology is the study of the Universe at large. Over the last several decades cosmology has developed into a huge subject, fueled by observations of ever greater scope and precision.

The Rosetta Stone of modern cosmology is the power spectrum of fluctuations in the Cosmic Microwave Background (CMB). The observed power spectrum agrees exquisitely well with the simplest prediction of the theory of inflation. Inflation postulates that the early (first 10⁻³⁵ seconds) Universe was dominated by the vacuum energy of an unknown scalar field, and that perturbations were produced by quantum fluctuations of this field. A major prediction, yet to be confirmed, is that inflation generates gravitational waves that, if the energy scale of inflation is at the GUT scale of 10¹⁶ GeV or above, should be detectable in the B-mode polarization of CMB fluctuations at large angular scales. If detected, such waves offer a window to physics at GUT-scale energies inaccessible to earthly experiment. In 2014 the BICEP2 team claimed a detection of B-mode polarization, but this proved to be from spinning dust in our Galaxy, not primordial.

Although the CMB is the most important observational pillar of modern cosmology, there are many other supporting observations. One of the reasons for confidence is that the weight of all the observations put together seem to support the same Standard \(\Lambda\)CDM Model of Cosmology.

This course aspires to cover the following topics (the first item is in capitals because of its importance):

THE LINEAR GROWTH OF FLUCTUATIONS IN PHOTONS, BARYONS, DARK MATTER, AND SPACETIME
General Relativity, applied to cosmology
Big Bang Nucleosynthesis
Recombination
WIMPs (Weekly Interacting Massive Particles) and other contenders for Cold Dark Matter
Cosmic Microwave Background
Inflation
Galaxy clustering
Weak gravitational lensing
Statistical methods

Warning: This is a graduate-level course that will require a serious amount of work on your part. I will cover the mathematics and physics as needed (including the general relativity), but in the lectures I will often have to fast-forward over details, which you can read more about in the texts.

Problem Sets

There will a problem set most weeks, 9 problem sets in all. Each set will be due before class the following Wednesday. They are intended to be frequent, and not too long. Problem sets count for 70% of your grade.

Please upload your solutions in pdf to canvas. Please make sure your solutions are easily readable before you submit them. Please attach any code that you created for your solution. Please credit any help as appropriate.

Project

In place of a midterm, there will be a Project, which will count for 15% of your grade.

Final

The final will be an open-book, take-home exam, due noon 10 December. It will be like an extra-long problem set. The final will count for 15% of your grade.

Grading

Grading will be weighted as follows:

Problem Sets 70%

Project 15%

Final 15%

Class is in-person

This is an in-person class. Class will not be available synchronously on zoom. However, classes will be recorded, and posted to canvas. My intention is to have the recording posted to canvas on the same day as the lecture. The canvas recordings are behind the CU firewall, accessible only to people in the class. By participating in the class, either in person or remotely, you agree to have your participation (image and audio) recorded.

CU rules prohibit you from recording the class separately.

AI

This course is open everything, including AI. As is the usual rule in science, you must credit any external source you use, including AI. If you find that AI helps your learning, please share that information with the class.

Students with Disabilities

The law requires us to make reasonable accommodations to students with learning or physical disabilities. If you need such accommodations, then you should tell me about them in a timely manner. Your first step is to contact Disability Services, who will assess your needs and let me know what accommodations I should provide.

Policies

Please consider the CU required syllabus statements as part of this syllabus.

Class conflicts that arise from student participation in all University-related extracurricular activities.

Common Courtesy

I expect you:

To give the class your full attention.

You may expect me:

To finish lectures on time.

R-E-S-P-E-C-T.

CMB from Planck Fall 2025 ASTR 5770 Homepage

Updated 2025 Aug 20