Ay126: Interstellar Medium

There is no single book that can cover both pedagogy and at the same time the astrophysics of ISM. Draine (Physics of the Interstellar and Intergalactic Medium) does a very good job on the latter. I will make use of a variety of sources for pedagogy. I would recommend that you buy a copy of Draine's book. Below "Chapter" refers to appropriate chapter in Draine's book.

The URL lists the errata and has problem sets and figures used in the book.


RESERVED BOOKS:
Astronomical spectroscopy : an introduction to the atomic and molecular physics of astronomical spectra by Jonathan Tennyson
Astrophysics of gaseous nebulae and active galactic nuclei by Donald E. Osterbrock, Gary J. Ferland
Atomic energy levels and Grotrian diagrams, vol. 1-4 by Stanley Bashkin and John O. Stoner, Jr
Introduction to atomic spectra by Harvey Elliott White

Interesting sites: J"orn Wilms, Erlangen-Nuremberg. Nice site of notes related to high energy astrophysics and atomic processes. Look under teaching (e.g. Astrophysical Radiation Processes"
Richard Mushotzky's collection, particularly good for X-ray astronomy.
HOMEWORK POLICY: You are free to discuss amongst yourselves. In fact, much of learning is peer-to-peer. Brain storming is good. However, true understanding comes from within and so there is a delicate balance between communal problem solving and deep contemplation. The latter will stand you in good stead. I suggest the following approach: do your best to solve the homework. Sometimes you simply cannot make a headway. Those problems are grist to group discussions. Please include the sole undergrad in your discussions. What you submit must your own work (typed, written, programmed, drawn).
GRADING FRAMEWORK: Two third will be determined by homeworks. The remaining one third will be a final exam. We need to discuss options.
VENUE & TIME: We meet in room 126, Cahill as follows: Tuesday 1-2p, Thursday 1-2 pm and Friday 1-2pm. The slot Monday 11a-12n is reserved for "backup" (I expect to miss 4 classes owing to unavoidable travel). The notation is as follows: "&" for classes that are makeup and "*" for the time I can meet any of you and review the material taught the previous week.
FINAL EXAM.You will be given a list of questions by Friday morning. The final exam can be found HERE.

Please sign up with the TA for "slots" (during the final exam week).


  1. Introduction I (April 4)
    Constants that you should know.
    From early Universe to present universe. Dark Matter Simulation (Steinmetz) . Simulation with gas (Hopkins) Red is million degrees gas, green is 10^4 to 10^5 K gas and magenta is cold gas.
    Pictorial Introduction.

  2. Introduction II (April 6)
    Pictorial introduction continued. Phases of ISM. Mass Flow. The curious equipartion of energy densities.
    The ionization potential of hydrogen is 13.6 eV. The optical depth for photons above this energy is very large. Thus elements and ions with ionization potential above 13.6 eV will not be ionized. Bearing this mind review Ionization chart  |  Ionization Table.
    HomeWork 1   |   due COB (TA's desk) April 13.  |  Solutions

  3. Atomic Spectra: The Beginnings (April 7)
    Kirchoff, Balmer, Rydberg, Hydrogen Spectrum, Alkali spectra (notation of spectral lines, SPDF).
    SRK summary
    SRK summary of Bohr & Schrodinger Model.
    For next class, please review Schrodinger solution. You may wish to read Hydrogen Wave functions (UMich, Chem461).
    For the advanced student I suggest, in addition, Schrodinger Model (UW Physics 2217).

  4. Orbitals, Periodic Table, Gross Structure (April 13)
    SRK notes on Orbitals & Periodic Table.
    Additional notes on the Periodic Table (U. Wisconsin Chem461).
    SRK summary of Alkali Spectra & Clue to Gross Structure (splitting of energy states due to angular momentum)
    A very useful and beautiful periodic table

  5. Fine Structure, Spectroscopic Notation & Hund's rule (April 14)
    SRK notes on the development of the concept of fine structure
    Relativistic Corrections and spin-orbit coupling. Please read pages 1-7
    SRK notes on LS Coupling
    HomeWork 2   |   Due COB (TA's desk) April 24   |   Solution

    Grotrian diagrams for elements of astrophysical interest
    Stancil's presentation on Fine Structure Lines
    For the curious student: Sci Am article on the detailed spectrum of hydrogen
    For the advanced student: In depth review of H atom

  6. Selection Rules, Helium Spectrum, Radiative Transfer (April 18)
    SRK notes
    Review Helium in view of Selection Rules. Radiative transfer (Chapter 7 of Draine's book)

  7. Basic Radiative Transfer, Einstein A&B Coefficent &Masers (April 20)
    Chapters 6, 7

  8. HI emission & absorption, Galactic Distribution of HI (April 21)
    Chaper 8  |  SRK notes

  9. Excitation and De-excitationn Rate Coefficients (April 24&; Makeup)
    Chapter 2

  10. Critcal Density & Results from Herschel (April 25)
    Chapter 17  |  SRK notes
    HomeWork 3   |   Due COB (TA's desk) May 2   |   Solution

  11. Warm Ionized Medium (April 27)
    Chapter 11

  12. Fine Structure in WIM (RISS, DISS) (April 28)
    Chapter 11   |   Lecture given by Harish Vedantham.
    Vedantham Notes   |   Presentation

  13. Photoionizaton (May 2)
    Extreme Scattering Events Vedantham Notes
    Chapter 13
    Review Saha equation, derive Milne relation.  |  Relate A coefficient to photon-absorption cross section.   |   Photoelectric cross-section

  14. Hydrogen & Helium Recombination (May 4)
    Chapter 14
    Oscillator strength  |  Case A & Case B  | 
    H recombination spectrum (Draine, Figure 10.2)
    Radiative recombination of Helium  |  Detailed Grotrian diagram for Helium (Draine, Figure 14.3)

  15. HII regions (May 5)
    Chapter 15 & 27
    Stromgren sphere  |  Timescales  |  Thermal balance
    Orion abundance: Heating  |  Cooling
    Metal poor & Metal rich: Heating  |  Cooling
    Density dependence Cooling (density dependence)
    HomeWork 4  |  Due COB, May 15  |  Solution by I. Escala  |  Additional constraint on density of intervening nebula by measurements of precise arrival time.

  16. Hot Ionized Medium: Halo & Circumgalactic Medium (May 9)
    Presentation: Studying Halo via HI, optical, UV & X-ray lines
    Reading: Putman et al. review on Galactic Halo  |  Gupta et al. review on Hot Halo (X-rays)  |  Circumgalactic Medium of M31  |  M31 byLehner

  17. Collisional Ionization Equilibrium & CIE Cooling Curves (May 11)
    Chapter 13, 34
    Key Point: (1) New processes that become important at high temperatures and (2) Collisional Ioinzation Equilibrium (CIE)
    Auger & Dielectronic Recombination  |  Presentation
    Other material: Ionization states under CIE (Review Figures 2-38)

  18. Ionization & Cooling timescales (May 12)
    Chapter 34 (Approach to CIE)
    SRK Notes
    Reading Material: Smith & Hughes (2010)

  19. Collisonless Shocks (May 16)
    Balmer dominated shocks (BDS):Model of Chevalier & Raymond  |  Presentation
    Review & Reading: Review by Ghavamian  |  Review by Heng  |  Collisional Excitation in Herbig-Haro shocks  |  Useful Atomic data

  20. Dust I (May 18)
    Chapter 21 (Observed Properties of Dust)  |  Draine IPMU Lecture 1
    Additional Material: Lecture on Dust by L. Hillenbrand
    HomeWork 5  |  Due COB, May 25

  21. Molecules I: (May 19; Hillenbrand)
  22. Molecules II: (May 23; Hillenbrand)
  23. Molecules III: (May 25; Hillenbrand)
  24. Star-formation (May 26; Hopkins)

  25. Dust II (May 30)

  26. Dust III (June 1)
    Big Particles (Babinet's theorem)  |  Small Particles: Rayleigh Scattering
    Draine IPMU Lecture 2
    X-ray halos

  27. Dust IV, Cosmic Rays (June 2)
    Heating (Chapter 25)

    Cosmic Rays: Why we care about Lowest Energy Cosmic Rays? Ionization of Hydrogen by Cosmic Rays
    Introduction  |  ISM & Astrochemistry