PHYS 755A Topics in Theoretical Physics: Astrophysics of Interstellar and Intergalactic Matter 


Syllabus, Fall 2010


Prerequisites: Consent of the Professor. The course assumes background in upper level undergraduate mechanics, quantum physics, and electromagnetic theory.


Professor: Varsha P. Kulkarni ; Office: 516 Main St., Room 101B; Phone : 777-6293, E-mail:




Lecture Hours: Fri. 1:00-3:00 pm, 516 Main St., Room 101B


Course Objectives and Learning Outcomes: The goal of this graduate course is to give students an overview of some of the key concepts in astrophysics, with emphasis on interstellar and intergalactic matter. Students will learn qualitative and quantitative aspects of ISM and IGM. By the end of the course, they will learn about radiative transfer, curve of growth, absorption line analysis. They will become familiar with the physics and chemistry of interstellar dust and molecules. They will get experience with special software used for line profile fitting, photo-ionization modeling etc. They will also learn about applications to distant galaxies through absorption lines in the spectra of quasars and gamma-ray bursts.


Required Textbook: “The Physics of the Interstellar Medium” by J. E. Dyson and D. A. Williams (Inst. Of Physics Publishing). Selected journal articles will also be discussed.


Other Useful References:


“Physics and Chemistry of the Interstellar Medium” by Sun Kwok (University Science Books).


“Introduction to Modern Astrophysics” by B. W. Carroll & D. A. Ostlie


“Astronomy Today” by E. Chaisson and S. McMillan (4th edition) ( For a qualitative overview of stellar, galactic and extragalactic astronomy)


“Dust in the Galactic Environment” by D. C. B. Whittet (Inst. Of Physics Publishing)


Some examples of reading assignments / seminar topics:


Pettini, M. 2003, Element Abundances through the Cosmic Ages, in Cosmochemistry. The melting pot of the elements. XIII Canary Islands Winter School of Astrophysics, Eds. C. Esteban et al. (astro-ph/ 0303272)


Petitjean, P. 1998, ``QSO Absorption Line Systems'', in the proceedings of the Les Houches school "Formation and Evolution of

galaxies"; O. Le Fevre and S. Charlot (eds.), Springer-Verlag [astro-ph/9810418]


Bechtold, J. 2003, ``Quasar Absorption Lines'', to appear as Chapter 4 in "Galaxies at High Redshift", Eds. I. P\'erez-Fournon, M. Balcells, F. Moreno-Insertis, F. S\'anchez, (Cambridge: Cambridge U. Press), p. 131 [astro-ph/ 0112521]


Tytler, D. 1982, ``QSO Lyman Limit Absorption'', Nature, 298, 427


Gunn, J. E., & Peterson, B. A. 1965, ``On the Density of Neutral Hydrogen in Intergalactic Space'', ApJ, 142, 1633


Lauroesch, J. T., Truran, J. W., Welty, D. E., & York, D. G. 1996, "QSO Absorption Lines and Early Chemical Evolution", PASP, 108, 641


Rauch, M. 1998, ``The Lyman-alpha Forest in the Spectra of QSOs'', ARAA, [astro-ph/9806286]


Loeb, A., & Barkana, R. 2001, ``The Reionization of the Universe by the First Stars and Quasars'', ARAA, 39, 19


Instructional Delivery Strategy: The students will learn the material through a combination of lecture/discussion sessions (20%), assigned readings  (50%), discussion of homework problems (10%), and seminars (20%). Most of the classes will consist of discussions of assigned readings/problems and/or student seminars on assigned topics. Student seminars will be approximately 30 min. long with 20 min. for discussion. Topics of all reading assignments and student seminars will be assigned so as to maintain a logical and sequential development of the topics listed below.


Course Requirements and Grading Basis: The grades will be determined as follows:


Reading/problem assignments and related discussions: 50%


4 Student seminars: 10% each


Class participation: 10%


Grading Scheme: The following will serve as a rough guide to grade boundaries. I may adjust these in the favorable direction for border-line cases.  >= 90: A, 84-89: B+, 77-83: B, 71-76:C+, 64-70: C, 57-63: D+, 50-56: D, < 50: F


Topical Outline:


The following topics will be covered in roughly the order given below:


Review of Basic Astrophysics


Introduction to Interstellar Matter


Observations of Properties of Interstellar Matter


Microscopic Processes—Heating, Cooling, Molecule Formation


Interstellar Dust


Nebulae—Excitation, Ionization


Introduction to Intergalactic Matter and Quasar Absorption Systems


Lyman-alpha forest--Redshift Evolution, Proximity Effect; Diffuse Intergalactic

Matter--Gunn Peterson Effect, reionization


Heavy-element Intervening Quasar absorbers--the Lyman-limit systems, damped Lyman-alpha systems


Analysis of Absorption Lines—Profile Fitting, Apparent Optical Depth Method


Photo-ionization Modeling—Use of CLOUDY


Absorption lines in quasars and gamma-ray burss; their implications for Galaxy Evolution and Cosmology


Attendance Policy: Attendance is mandatory and active participation in class is expected. The questions on the tests will be based on material discussed in the lectures, some of which will not be in the text book.



Students with Disabilities: If you have a disability, it is essential that you speak to me early in the semester to make the necessary arrangements to support a successful learning experience. Also, you must arrange to have a Letter of Accommodation sent to me from the USC Office of Disability Services.