Physics 372, Extragalactic Astronomy and Cosmology: Spring 2025

This material can be found online at URL

http://spiff.rit.edu/classes/phys372/phys372.html

Outline for the course, class schedule, etc.

Lectures

• Week 1, Day A: Intro to the course, cosmological teasers
• Week 1, Day B: Parallax -- what is it?
• Week 1, Day C: Parallax -- uncertainties and bias
• Week 2, Day A: No class
• Week 2, Day B: Review of stellar properties (all based on parallax!)
• Week 2, Day C: Using stellar spectra to estimate distances
• Week 3, Day A: Clusters of stars
• Week 3, Day B: Clusters of stars II: How far do they reach?
• Week 3, Day C: Distance Ladder exercise
• Week 4, Day A: How to determine distances with eclipsing binary stars
• Week 4, Day B: Using pulsating stars I: RR Lyrae
• Week 4, Day C: Using pulsating stars II: Cepheids
• Week 5, Day A: News and questions
• Week 5, Day B: Tip of the Red Giant Branch (TRGB)
• Week 5, Day C: Surface Brightness Fluctuations (SBF)
• Week 6, Day A: Distances from the globular cluster luminosity function
• Week 6, Day B: The Milky Way Galaxy I: Structure
• Week 6, Day C: The Milky Way Galaxy II: Mass
• Week 7, Day A: Other galaxies: basic classification (bring laptop with you if possible for an interactive exercise)
• Week 7, Day B: Other galaxies: Jargon
• Week 7, Day C: Midterm
• Week 8, Day A: Galaxies in optical vs. infrared
  Please watch the Zoom recording of my lecture to see how you can access and display images for the exercise associated with this class.
• Week 8, Day B: Guest: Rebecca Larson on "How to detect high-redshift galaxies"
• Week 8, Day C: No class
• Spring Break (Mar 12 - 19)
• Week 9, Day A: Active Galaxies I
• Week 9, Day B: Active Galaxies II
• Week 9, Day C: Supermassive Black Holes -- do they really exist?
• Week 10, Day A: Using masers to measure a "geometric" distance
• Week 10, Day B: The Tully-Fisher relationship (spirals)
• Week 10, Day C: The Fundamental Plane (ellipticals)
• Week 11, Day A: Supernovae: overview and using EPM on Type II
• Week 11, Day B: Supernovae: can we use Type Ia SNe as standard candles?
• Week 11, Day C: Gravitational lensing I
• Week 12, Day A: Gravitational lensing II
• Week 12, Day B: Cosmology -- the (local) expanding universe and H₀
• Week 12, Day C: The mystery of "impossibly young" galaxies
• Week 13, Day A: The Cosmic Microwave Background I: Maps of the microwave sky
• Week 13, Day B: The Cosmic Microwave Background II: Origin and Redshift
• Week 13, Day C: The Cosmic Microwave Background III: Structure ; Dynamics of a simplfied universe
• Week 14, Day A: Adding Λ (lambda) to the mix
• Week 14, Day B: What else can we learn from the CMB?
• Week 14, Day C: The Hubble Tension (at last)
• Week 15, Day A: Day of review and news
• Posters due for Final Exam: Wed, Apr 30, 10:45 AM.
  • Guidelines for making a good poster

Homework sets

In order to use the on-line homework system, you need to know your login name and have a means of two-factor authentication. Your "login name" should be the same as your last name, but with lowercase letters only; something like richmond. You'll need to use some sort of 2FA application, such as Duo Mobile.

0. Introduction to Webwork system due Thursday, Jan 16, at 5:00 PM.
   • Answers to Homework 0
1. Trigonometric parallax due Friday, Jan 24, at 5:00 PM.
   • Answers to Homework 1
2. Clusters of stars due Friday, Feb 7, at 5:00 PM.
   • Answers to Homework 2
3. Variable stars due Friday, Feb 14, at 5:00 PM.
   • Answers to Homework 3
4. Secondary distance indicators due Friday, Feb 21, at 5:00 PM.
   • Answers to Homework 4
5. Analysis of galaxy classification exercise due Tuesday, Feb 24, at 11:59 PM.
   This is NOT a WebWork exercise; instead, you need to look at a series of galaxies in class and classify them in a spreadsheet; then submit a copy of the spreadsheet via myCourses, under Galaxy classification exercise
6. Galaxies in the optical vs. the infrared due Wednesday, Mar 5, at 11:59 PM.
   This is NOT a WebWork exercise; instead, you need to examine one galaxy at optical and infrared wavelengths, and answer some questions about its appearance. Submit a copy of your answers, together with a screenshot of your galaxy, in myCourses, under Comparison of galaxies in optical and IR
7. Active Galaxies, Tully-Fisher, Faber-Jackson due Friday, Apr 4, at 5:00 PM.
   • Answers to Homework 7
8. Using supernovae to estimate distances due Friday, Apr 11, at 5:00 PM.
   • Answers to Homework 8

Extra Credit Projects

The deadline for extra credit assignments is 5 PM, Mon, Apr 28. All work must be submitted to the instructor by this time to count towards your grade.

1. Create an HR diagram using Gaia DR3 data
2. Make a map of the original Federation of Planets
3. What is the most distant galaxy to which the TRGB method has been applied?

For more information:

• I've taught vaguely related courses in the past.
  • SPSP 240: Extragalactic Astronomy and Cosmology (long ago, basic level)
  • SPSP 443: Extragalactic Astronomy and Cosmology (not so long ago, moderate level)
  • The Extragalactic Distance Ladder (grad course at Univ of Tokyo)

This page maintained by Michael Richmond.