AST 393

Survey of Interstellar Medium

Spring 1999

TTH 2:00 - 3:30 p.m.
RLM 15.216B
Unique No. 44160

Office: RLM 17.344
Phone: 471-4396
Office Hours: T 3:30 - 4:00 p.m., W 2:30 - 3:00 p.m.

REQUIRED TEXTS: The Physics of the Interstellar Medium, by Dyson and Williams (DW)
Physical Processes in the ISM, by Lyman Spitzer (S)
EXAMS AND GRADING: There will be homework, three exams, and one comprehensive final. Class discussion and questions are appreciated and will be rewarded with credit. The homework is important in providing a basis for understanding the tests. The course grade will be determined according to the following plan:
Top two exam scores 20% each
Final exam 30 %
Homework and Class Participation 30 %

GOALS OF THE CLASS: The primary goal of the class is to help students develop an understanding of the physical processes at work in the interstellar medium; this goal provides the organizing framework for the course. A secondary goal is to introduce students to the different components of the interstellar medium, which span an enormous range of conditions. The role of the interstellar medium in forming stars will be discussed in some detail, and the return of matter and energy from stars to the interstellar medium will also be covered. In addition to the connections to stars, the ISM is connected through disks around forming stars to the origin of planetary systems and life. The larger scale issues of star formation in galaxies as a whole and in the early Universe will be discussed.


  1. Observational Overview (S1, DW1,2)
    The different components of the ISM and where they are

  2. Dust (DW4, S7, S8)
    Opacity, Polarization, Composition of dust particles

  3. Chemistry (DW3, DW5, S5)
    Ionization and chemical equlibria and processes
    Observations of abundances

  4. Excitation (S4)
    Radiative and collisional excitation, pumping, masers
    Observations of Excitation and their interpretation

  5. Energetics (S6, S9 DW3, DW4)
    Heating and cooling of gas and dust
    Radiative equilibrium
    Application to different components of ISM

  6. Dynamics (DW6, S10)
    Virial Theorem, thermal and turbulent velocities, shocks, waves

  7. Star Formation (DW8, S13)
    Collapse theory and observations, Disks and outflows
    Massive star formation

  8. Aftermath of Star Formation (DW5, DW7, S12, S9.4)
    HII regions, Winds, Planetary Nebulae, Supernova remnants

  9. ISM on a Galactic Scale (DW7.4, DW7.5)
    2, 3, many phase models, galactic haloes, fountains, supershells
    Distribution of phases in Galaxy, other galaxies

  10. Star Formation on a Galactic Scale
    Star Formation in Milky Way, nearby galaxies
    Starbursts, Ultraluminous Galaxies
    Star formation at high redshift