Astro 381c (Unique 49090)
Spring 2010: Tu Th 9.30 to 11.00, RLM 15.216B
Instructor: Prof. Shardha Jogee (RLM 16.224, sj@astro.as.utexas.edu; 512-471-1395). Office hours: Thursdays from 1pm to 2pm, or by appointment
Course Description: This course focuses on a clasical treatment of stellar dynamics and its application primarily to galaxies and stellar clusters (e.g., open clusters and globular clusters), with some brief discussion of other astrophysical systems. However, the general principles discussed in class can be applied and adapted to a broad array of astrophysical situations by able graduate students working in different areas (e.g., galaxies, stars, planets, black holes, etc). Since the formal treatment of stellar dynamics in the course textbook can appear quite dry, I will complement it in several ways:
- While the course will focus on stellar dynamics, I will initially adopt a unified approach and emphasize general principles that apply to both fluid (gas) and stellar systems.
- I will include numerous examples that illustrate how the principles can be applied to real astrophysical systems, ranging from open clusters, globular clusters, proto-planetary disks, elliptical and disk galaxies, groups/clusters of galaxies, to superclusters. You will also be encouraged to think on and discuss how the principles of gravitational dynamics apply to your own research.
- We will discuss alternative derivations that are physically intuitive even if they provide less exact answers.
The course outline lists the topics to be covered in class and will be regularly updated as the semester proceeds.
- A treatment of gas dynamics is beyond the scope of this course. However, since gas is a key component of galaxies and many other astrophysical systems, we will discuss a few relevant examples: (a) The stablility of gas and stellar disks, the Toomre Q parameter and the the condition for gravitational instabilities in galactic disks; relation to star formation. (b) Gas transport and the fueling of gas into starburst and active galactic nuclei. (c) Swing amplification in gas and stellar disks
Pre-Requisites: This course is targetted at graduate students in astronomy and astrophysics. I will assume the following: (1) Standard undergraduate level physics preparation; (2) Mathematical physics background, especially vector calculus, at level of Arfken (1970) or Matthews and Walker (1970). This is reviewed in Appendix 1.B of the main textbook ("Galactic Dynamics") as well; (3) Basic astronomy background, reviewed in Chapter 1, section 1.1 of "Galactic Dynamics".
Textbook and Reading: The main course textbook is "Galactic Dynamics" (GD) by J. Binney & S. Tremaine. If you are buying a new copy, get the second edition (2008; Princeton Unviersity Press), but if you already have the first edtion (1987; Princeton Unviersity Press), it will do fine for the most part. However, note that in the two editions, the order of Chapters 7 and 8 is swapped, Chapter 9 is different, and Chapter 10 on dark matter is removed from the second edition. Here is a list of errata for the second edition.
There will be extra reading material posted on the class website as the semester proceeds. Complementary textbooks for additional optional reading include: (1)"Galactic Astronomy" (GA) by J. Binney and M. Merrifield (2) Landau and Lifshitz (1959) on hydrodynamics; (3) Statistical Mechanics by Huang (1987).
Course Grade
The final grade will be divided as follows :
- 65% = Homeworks
- 20% = Exam
- 15% = Quiz
There will be about 5 homeworks, 1 end-of-semester exam, and 1 mid-semester quiz. There will also be small in-class assignments that can count toward extra credit and help you if your grade is borderline between two letter grades.
When converting your final numerical grades to letter grades, I will use the scheme below or one that is slightly more lenient: A= 85% to 100%; B= 70% to 84%; C= 60% to 69%; D= 50% to 59%; F= 0% to 49%.
Class Policies: There will be makeup exams only for students having a valid excuse and an official note from UT for the specific date and time of the missed exam. You are encouraged to study with other students, but you must write up your own homework, exams, and quizzes. Cheating will be severely punished: if you copy someone's homework/quiz/exam or let someone copy yours, both of you will receive zero credit, and we will consider filing a report to the Dean of Students.
The exam will cover primarily the material covered in class
after the mid-term quiz: this material corresponds to sections
V to IX in the
course outline.
However, the exam can also include essential concepts covered
earlier, such as
- basic timescales: trelax, tcoll, tcross
- the expressions for Potential Phi (e.g., Eq 9 on lecture of
Tu Feb 9), the gravitational force F, the circular speed Vc,
the escape speed Ve, and the total Potential energy W for a
spherically symmetric potential
- the epicyclic approximation and an expression for kappa when
circular motions dominate