First-year PhD Astrophysics Reading Group, 2007 version

Astrophysics is a huge and diverse discipline. Nevertheless, there is a body of knowledge, ideas and jargon that should really be familiar to everyone, whatever their detailed field of research. In the space of a 3-year PhD, getting to grips with this material is not easy, but it is important to get at least some feel for the basics early on.

Therefore, we will be having a crash course that attempts to get through the most important topics in a concentrated burst at the start of the PhD. The idea is that the first-year students plus moderator(s) will meet regularly to discuss the material on the reading list below. This is like the fabled Kamikaze system, in that the sessions will be interactive discussions - no sitting back and passively absorbing (or not) lectures. In order to stimulate this attitude of engagement, there will be a weekly problem for which everyone should hand in a written answer.

However, the difference is that complete mastery of all the details is not expected. This is the real world: the material is out there, and professional astrophysicists have to develop a working familiarity with it - often in far less time than would be ideal. At the most basic level, this means being able to decode the jargon. With luck, the ideas will be sufficiently exciting that readers will be motivated to dig into the details of some derivations. In coming together and talking over the material, it should be possible to share these insights. The main thing is to cover the territory as thoroughly as possible given the limited time (as a guide, it is envisaged that all preparation for the groups should not take a majority of your time - say up to 1 working day total per tutorial). This will at least provide an introduction to some of the more useful textbooks, and lay the foundation for more detailed specialized study.


In previous years, the group met twice per week for one term. In response to customer feedback, this has now been changed to once per week for two terms. Unless otherwise announced, the default time will be 10-11 a.m. on Thursdays.


The ROE lecture theatre, which should normally be free. In cases where this is in use (e.g. the ROE conference on Oct 25), the ROE common room is the backup location.


Avalable in reference section of ROE library. Please xerox the relevant bit and leave the book for others to use. There are plenty of alternatives; reading these as well is not forbidden.....

Binney & Merrifield, Galactic astronomy
Dyson & Williams, The physics of the interstellar medium
Jackson, Classical electrodynamics (3rd [SI] edition)
Lena, Observational astrophysics
Longair, High-energy astrophysics (2nd edition: 2 vols)
Peacock, Cosmological physics (apologies...)
Phillipps, The physics of stars
Press et al., Numerical recipes (2nd edition)
Rybicki & Lightman, Radiative processes in astrophysics

Hand-in questions

It is easy enough to convince yourself that you understand a piece of reading, but the acid test is to use the material. Therefore, so that everyone can gauge for themselves whether the reading is sinking in, there will be a series of questions associated with the group, at a frequency of roughly one per week. These were originally classed as "hand-in" to force people to try them; but this is a bit artificial, since they are not marked. We therefore have an honour system, where students are expected to make an independent effort to produce a full written solution to the problem that goes with a given piece of reading. Possibly you will fail - in which case come to the tutorial with some relevant points in mind that you want to see clarified. If you still can't do the problem afterwards, even after some discussion with other students, you should bring your partial solution to the relevant tutor and ask for advice. But most of the time, the problems should get solved without the need for formal scrutiny.

The list of questions may be subject to change as the sessions progress.


Subject to change as the sessions progress. Name of the tutor for a given session is in [brackets].

Date: October 4 [JAP]
Topic: Radiation basics
Jargon: specific intensity; surface brightness; Planck function; Einstein coefficients; radiative transfer; optical depth; scattering; extinction
Reference: Rybicki & Lightman p1-39

Date: October 11 [PNB]
Topic: Astronomical measurements
Jargon: Celestial coordinates; parallax; proper motion; magnitudes; colours; K-corrections
Reference: Binney & Merrifield p26-61

Date: October 18 [ERT]
Topic: Astronomical signals
Jargon: Fourier transform; sampling; Nyquist frequency; aliasing; convolution; FFT; filtering; signal-to-noise
Reference: Press p490-499 and 530-535 (Fortran edition. Add about 7 pages for the C edition); Lena p81-95 and p116-140

Date: October 25 [AFH]
Topic: Telescopes
Jargon: diffraction limit; wavefront; pupil; adaptive optics; interferometry; uv plane; aperture synthesis
Reference: Longair Vol 1 p216-236; Lena p218-262

Date: November 1 [JAP]
Topic: Detectors and spectrographs
Jargon: shot noise; dark current; flat field; background limit; noise temperature; brightness temperature; diffraction grating; blaze
Reference: Longair Vol 1 p237-260; Lena p274-308

Date: November 8 [IPRN]
Topic: Statistics and data modelling
Jargon: distribution function; central limit; variance; standard error; skewness; chi-squared; KS test; correlation; rank test; maximum likelihood; covariance matrix; confidence limits
Reference: Press p603-619, p630-635, p650-662, 684-693 (Fortran edition. Add about 7 pages for the C edition); Lena p96-115

Date: November 15 [JAP]
Topic: Matter & radiation
Jargon: ideal gas; degeneracy pressure; radiation pressure; Saha equation
Reference: Phillips ch2

Date: November 22 [JAP]
Topic: Astrophysical plasmas
Jargon: Plasma frequency; flux freezing; Alfven waves; Faraday rotation
Reference: Rybicki & Lightman p224-231; Jackson p319-322; Longair Vol 1 p307-312

Date: November 29 [ERT]
Topic: Bremsstrahlung
Jargon: Gaunt factor; free-free emission and absorption; cooling function
Reference: Longair ch3; Rybicki & Lightman p155-162

Date: December 6 [AFH]
Topic: Synchrotron radiation
Jargon: gyrofrequency; relativistic beaming; polarization; self-absorption
Reference: Longair ch18; Rybicki & Lightman p167-175

Date: December 13 [JAP]
Topic: Comptonization
Jargon: Compton and inverse Compton scattering; synchrotron self-compton; Kompaneets equation; SZ effect
Reference: Longair ch4; Rybicki & Lightman p195-216

Date: January 10 [JAP]
Topic: Line radiation
Jargon: recombination; forbidden lines; critical density; ionization parameter; doppler width; voigt profiles; curve of growth
Reference: Rybicki & Lightman ch10; Peacock p361-365 and 429-430

Date: January 17 [WKMR]
Topic: Star-forming regions
Jargon: outflows; ambipolar diffusion
Reference: Dyson & Williams ch8

Date: January 24 [PNB]
Topic: Energy generation & transport in stars
Jargon: pp chain; CNO cycle; Gamow peak; opacity
Reference: Phillips ch4

Date: January 31 [PNB]
Topic: Stellar structure and evolution
Jargon: hydrostatic equilibrium; virial theorem; radiative diffusion; main sequence
Reference: Phillips ch5; Longair Vol 2 p52-91

Date: February 7 [ERT]
Topic: Gas dynamics and shocks
Jargon: shock adiabat; compression ratio; isothermal shocks; collisionless shocks; similarity solutions
Reference: Dyson & Williams ch6

Date: February 14 [RJM]
Topic: Active galaxies
Jargon: Seyferts; UVX; blazars; broad and narrow lines; superluminal motion; unification and tori; Magorrian relation
Reference: Peacock ch14

Date: February 21 [RJM]
Topic: Accretion
Jargon: thin disks; accretion efficiency; Eddington limit
Reference: Longair ch16

Date: February 28 [ANT]
Topic: Observational cosmology
Jargon: RW metric; comoving distance; Friedmann equation; density parameter; luminosity distance
Reference: Peacock p65-92