Galaxies & the Milky Way: Ph 443/543 and Astro 443 Spring 2007

General Description

Logistics

This website is maintained by the lecturer, Dr. Jerry Sellwood. I may be found in room 308 in the Physics & Astronomy Building, Busch Campus, telephone 445-5287, e-mail: sellwood_at_physics.rutgers.edu

Classes are Tuesdays & Fridays at 10:20 am in room 217 of the Science and Engineering Resource Center (SEC). I will declare an office hour on request, but I prefer to keep it informal and to be available more or less any time.

Normal lectures will continue until April 13. I will be out of town on April 17, so term paper presentations will take place in the classes on April 20, April 24, April 27 and May 1. A class on May 1 seems the simplest solution to make up for the missed class, even though it is the first day of the normal reading period. I will assume it is OK unless I hear a solid complaint. If this schedule is acceptable, term papers are due Friday April 13.

Lecture notes

Some notes for my lectures will be posted on this page shortly before each class. Jan 16, Jan 19, Jan 23, Jan 26, Jan 30, Feb 2, Feb 6, Feb 9, Feb 13, Feb 16, Feb 20, Feb 23, Feb 27, Mar 2, Mar 6, Mar 9, Mar 20, Mar 27, Mar 30, Apr 3, Apr 6, Apr 10, Apr 13

Homework assignments

Assignment #1 is avaliable here and is due on Jan 26. Solutions are here

Assignment #2 is avaliable here and is due on Feb 6. Solutions are here

Assignment #3 is avaliable here and is due on Feb 16. Solutions are here

Assignment #4 is avaliable here and is due on Feb 27. Solutions are here

Assignment #5 is avaliable here and is due on April 3. Solutions are here

Overview

Over the past 100 years, astronomy has really taken off as a science. We now know of billions of galaxies scattered throughout the universe. The Milky Way, which we inhabit, gives us some unique insights, but our close-up view makes it difficult to see the Galaxy as a whole. The Milky Way is a member of the Local Group of galaxies, which includes Andromeda and M33 and a number of dwarf galaxies. The Local Group lies on the outskirts of the Virgo cluster of galaxies, in a relatively dense part of the universe. We now know that galaxies are uniformly distributed only when averaged over volumes of $\sim 100\;$Mpc in diameter; on smaller scales, galaxies are arranged in filaments, sheets and clusters that surrounding huge voids.

The origin of this clustering hierarchy is one of the major questions of cosmology, but galaxies themselves present a number of serious challenges to physicists. What are they made of? How old are they? Why do they have their observed shapes and sizes? What are the physical reasons for the variety of shapes? Have they evolved much over time? Why do they have massive black holes in their centers? Did the BHs form first, or are they the result of galaxy evolution? But above all: why galaxies?

The apparent masses of galaxies greatly exceed that estimated for the stars we can see, and the excess mass is generally called dark matter. Decades after the discovery of mass discrepancies, we still have no clear idea of the nature of the dark matter. How is it related to the luminous galaxies we see? To what extent does the DM influence/control the galaxy? Answers to these questions offer us a means to constrain some of its properties.

Text

The text I recommend for this course is Galaxies in the Universe: An Introduction by Linda Sparke and John Gallagher, published by Cambridge University Press. The course will follow this book reasonably closely. An enthusiastic student who would like a more substantial text, covering a similar selection of topics in greater detail, might also look at Galactic Astronomy by James Binney and Mike Merrifield, published by Princeton University Press.

Assessment

There will not be any exams. I will assign several homework sets, and scores will contribute to the course grade. I will require a term paper the end of the semester on a topic of your choice from within the material of the course, which students must present to the class. I will try to encourage discussion of the material in class, and participation in these discussions will be a small part of the assessment.

Tentatively, I will assign grades based on scores for homework (50%), the term paper (40%), and participation and attendance in class (10%).

Term paper

The term paper should be on a topic closely related to the course. The paper should explain why the selected topic is interesting and should include your own assessement of the principal challenges (observational or theoretical) facing your selected topic. It should assume knowledge gained from the course. The paper must go into more detail than in the lectures. Undergraduate students may present a more in-depth study of some topic from the books. Graduate students must cite and discuss papers from the recent literature, and must present more than simply a summary of one or two papers - I would like to read what did, or did not, impress you about each paper. Feel free to throw in an idea or two of your own as well.

I would prefer you to select your own topic, but I can suggest ideas if you are stuck. You should let me know your topic by the end of February. I may suggest that you narrow it down or broaden it, if appropriate, and can suggest additional references that you would find helpful.

The term paper will count 40% of your grade and will be assessed in three parts:

Students with Disabilities

If you have a disability, you are urged to speak to Dr Sellwood early in the semester to make the necessary arrangements to support a successful learning experience. Also, you must arrange for Dr Sellwood to receive a letter from your College's Disability Concerns Coordinator verifying that you have a disability. A list of the College Coordinators can be found at here.

Astronomy on the web

An enormous amount of astronomical information is available on the web. This is a good web page to start from for general astronomical information. There are a couple of very useful search engines for articles from the modern astronomical literature. All Journal articles are indexed, and most are retrievable, from here. Preprints in most branches of physics are posted here with those in astronomy on astro-ph.

Ordering of material