Course 690, Topics in Astrophysics II
"High Energy Astrophysics"
Spring 1997
Professor: Jack Hughes, Serin 307W, x5-0980
Meets: Wed 1:10-2:30PM (SEC 211) Fri 2:50-4:10PM (SEC 210)
Text: "High Energy Astrophysics" by Malcolm Longair
(Cambridge University Press) Vols 1 and 2
General Description
The Universe is filled with diverse objects and phenomena ranging from
those with very low characteristic temperatures, such as the 2.7 K
Cosmic Microwave Background Radiation, to the ultrahigh energy cosmic
rays in which a single particle can carry 10 J or more of energy.
Accordingly in order to attempt a complete understanding of cosmic
objects and events, astrophysicists have been driven to conduct
studies over the entire electromagnetic spectrum. In this course, the
focus will be on the study of high energy astrophysics, that is to
say, the field of astronomy that concerns itself with objects and
phenomena having a characteristic temperature greater than about 10^6
K or equivalently 0.1 keV. This includes the X-ray and gamma-ray
bands of the electromagnetic spectrum, cosmic rays, and neutrinos from
the Sun and supernovae. The field is relatively new: cosmic rays were
discovered in 1912 (although not explained as high energy particles
until 1929) and, although, X-rays were discovered by Rongten in 1895,
X-ray astronomy wasn't born until 1949 when the Sun was discovered as
the first extraterrestrial X-ray source. In general the history of
X-ray and gamma-ray astronomy has paralleled the history of space
exploration. Neutrino astronomy is even younger, commencing with the
Homestake gold mine experiment in the 1970's which gave rise to the
famous "solar neutrino" problem.
This course is intended to provide the student with sufficient
background material and knowledge in order to appreciate current
research literature in high energy astrophysics. It will draw on
graduate level physics and astronomy as prerequisites. Although the
text listed above is required, some course material will be taken from
other sources, such as "Radiative Precesses in Astrophysics" by
Rybicki and Lightman (Wiley), particularly for lectures on radiative
processes. Students might consider looking at the readable book on
X-ray astronomy "Exploring the X-ray Universe" by Charles and Seward
(Cambridge).
Assessment
The grading criteria for this course are divided equally between
problem sets, and a term paper. An oral class presentation on the
term paper topic is also required. Examples of possible term paper
topics are listed as "Other topics". Please choose your topic in
consultation with Professor Hughes.
Other topics
The X-Ray background, gamma-ray bursts, origin of
cosmic rays, the nature of dark matter, solar
neutrinos, the early Universe
Topic Outline ("as done")
- Lecture 1 (1/22): Overview/Historical introduction
- Lecture 2 (1/24): Ionization losses of high energy particles
interacting with matter
- Lecture 3 (1/29): Photon interactions with matter: Photoelectric
effect, Compton scattering
- Lecture 4 (1/31): Photon interactions: pair production
High energy particle and photon detectors
- Lecture 5 (2/ 5) Telescopes and Observatories
- Lecture 6 (2/ 7) Bremsstrahlung
- Lecture 7 (2/12) Bremsstrahlung, radiative recomb (Milne relation)
- Lecture 8 (2/14) Line radiation, ion & recomb rates, ionization balance
- Lecture 9 (2/19) Cyclotron radiation/Synchroton radiation
- Lecture 10 (2/21) Synchroton radiation
- Lecture 11 (2/26) Synchroton/Blackbody/Inverse Compton scattering
- Lecture 12 (2/28) Inverse Compton scattering/Kompaneets eqn.
- Lecture 13 (3/ 5) SNe (Supernovae): Rates/Types/progenitors
- Lecture 14 (3/ 7) SNe: Explosion mechanisms/SNRs: Intro, Crab Nebula
- Lecture 15 (3/12) SNRs (Supernova Remnants): nonthermal (equipartition)
- Lecture 16 (3/14) SNRs: thermal: shock waves, Sedov solution
- Spring Break
- Lecture 17 (3/26) SNRs: thermal: other evolutionary issues, Coloumb
equil., NEI
- Lecture 18 (3/28) SNRs: finish/COGs (Clusters of Galaxies): intro
- Lecture 19 (4/ 2) COGs: Optical/X-ray classifications, luminosity
functs.
- Lecture 20 (4/ 4) COGs: Correlations, origin of Fe
- Lecture 21 (4/ 9) COGs: Physical processes: sound speed, mean free
paths, T equilibration timescales, heat conduction,
convective stability, radiative cooling
- Lecture 22 (4/11) COGs: X-ray structure, temp, binding masses
- Lecture 23 (4/16) COGs: SZ effect in clusters/ AGN: Historical intro
- Lecture 24 (4/18) AGN: Seyfert Galaxies/Unified Scenario
- Lecture 25 (4/23) AGN: Broad Fe lines / Chan's presentation
- Lecture 26 (4/25) Student presentation: Xie & Jacobs
- Lecture 27 (4/30) Student presentation: Debattista & Sluis
- Lecture 28 (5/ 2) Student presentation: Maljian & O'Connell