The LHC accelerates protons to kinetic energies of up to 7000 times their rest
mass—a huge technological
achievement. Yet, every second, over 500 million particles with energies greater than this collide with the
Earth. Where do these particles come from, and how are they accelerated to these astonishing energies?
These are, in fact, still open questions in astrophysics. In this module, we will look at the observational
evidence for particle acceleration in astrophysical objects, the mechanisms available to accelerate
particles, and some of the likely sources, including supernovae and supernova remnants, neutron stars,
and active galaxies.
This course aims to
- present the evidence for high-energy
processes in astrophysics, in both the electromagnetic
spectrum (from gamma rays to radio) and in high-energy
particles (cosmic rays and neutrinos);
- describe the techniques and instruments used to detect high-energy
particles from astrophysical sources (gamma rays, neutrinos and cosmic rays);
- discuss the mechanisms by which particles can be accelerated to high energies in astrophysical
- identify and describe those classes of astrophysical objects that provide such an environment,
in particular supernovae and gamma ray
bursts, pulsars and supernova remnants, and active
- discuss remaining open questions and future prospects in the field of particle astrophysics.
On successful completion of this course, you should be able to:
- describe the mechanisms by which electromagnetic radiation is produced in the presence of a
population of fast particles, namely synchrotron radiation, bremsstrahlung, the inverse Compton
effect and neutral pion decays;
- explain how cosmic rays, TeV gamma rays and neutrinos are detected by current and planned
- summarise the observational evidence, from electromagnetic radiation and other observational
signals, for the presence of populations of high-energy
particles in some astrophysical objects;
- derive expressions relating to diffusive shock acceleration in astrophysical environments;
- explain the constraints that the observations place on the nature of astrophysical sources;
- give a list of candidate source types, and describe the physical conditions therein and the
observational evidence for populations of fast particles in these objects;
- explain how observations can be used to distinguish different production mechanisms and discuss
the importance of coordinated observing campaigns at different wavelengths;
- summarise the current state of knowledge in the field and discuss possible future developments.
The assessment for this course will consist of:
- an end-of-semester exam (85%)
- Rubric: answer question ONE (compulsory: 30 marks) and TWO other questions (20 marks each).
A practice exam paper will be provided.
- five short class tests (5×3%)
- These will be in lecture slots and will test your knowledge and understanding of the taught material.