High Energy Astrophysics and Radiative Processes
Ph 442 --- Fall 2007

This is an advanced undergraduate-level course on some of the most energetic objects and phenomena in the universe. Examples are supernovae, gamma ray bursts, and neutron stars and black holes that are accreting matter from their surroundings. Most of what we know about such objects comes from the study of x-ray and gamma-ray photons arriving at Earth. Some information also arrives in the form of energetic elementary particles --- cosmic rays. The processes that produce these energetic photons and particles are often non-thermal, i.e., the spectrum is far from that of a black body, so we will need to study these processes in order to deduce the properties of the source from the emitted spectrum. We will also study how x-rays and gamma-rays are detected.

High energy astrophysics is a very active area of astronomy today, with at least seven orbiting observatories in operation. As part of the class, you will analyze data from some current and past satellites.

Prerequisite: Physics 361 - Quantum Mechanics and Atomic Physics; Physics 385-386 - Electromagnetism

Handouts

• Syllabus 
• Major Milestones in X-ray Astronomy
• Homework 1 (Due: September 13, 2007)
  • Solution
• The long-promised Homework 2  (Due: October 2, 2007)
  • WebPIMMS website needed for problem 2.
  • WebSpec website needed for problem 3.
  • Solution; See the paper version for the figures.
• Homework 3  (Due: October 16, 2007)
  • Solution
• Homework 4  (Due: November 13, 2007)
  • Solution.
• Homework 5  (Due: November 29, 2007)   Problem 4 is now present.
  • Crab Nebula images for problem set.
  • Solution. This version corrects an error in Equation (7) that was pointed out to me by a member of the class. The resulting increase in the expected deflection of energetic cosmic rays casts doubt on the possible correlation between the directions from which cosmic rays arrive and the directions to active galactic nuclei.
    The mean grade was 83.6/100.
• Homework 6  (Due: December 11, 2007)
  • Solution. The mean grade was 75.4/100.

Other Resources

• High Energy Astrophysics Picture of the Week
• X-ray Detectors Overview: Introduces and provides some details about x-ray detectors used for astronomy.
• Space Science Instrumentation Notes: These come from a class taught at the Mullard Space Science Laboratory of the University College London. Useful sections are page 3 for a discussion of CCDs, page 4 for a discussion of photomultipliers, and page 5 for a discussion of x-ray optics.
• CCD Detectors (html, pdf): These are slides from a presentation at the 5th International X-ray Astronomy School. Though aimed at graduate students and providing more detail than needed for this course, the beginning slides are a nice introduction to the basics of CCD detectors.
• X-ray Optics: Slides from the 5th International X-ray Astronomy School. They go into more detail than necesary for this course. They do (briefly) demonstrate that a paraboloid brings all rays entering parallel to the axis of symmetry to a single focus.
• Schematic supernova spectra
• SNIa spectrum -- the contribution of different elements to a SNIa spectrum.
• Supernova Taxonomy -- note the chart in particular. Though also not that it is not clear whether the different types are illuminating or obscuring the fundamental physical mechanisms.
• SN1987a Rings: This is before the impact of the expanding debris.
• SN1987a --- the impact of the debris on the inner ring observed in visible light with the Hubble Space Telescope and in X-rays with Chandra.
• Core collapse supernova review article by A. Mezzacappa. This article is the source of the color figures that I showed in class. The introduction should be understandable, though most of the article includes more detail than is appropriate for our course. (I can see this article from my office computer, let me know if it is not generally accessible.)
• Where, Oh Where Has the r-process Gone; A recent review article for anyone that wishes to see much more detail about the r-process. (Also available as arXiv:0708.1767.) Here is another quite detailed review: arXiv:0705.4512.

Active High Energy Astronomical Observatories

• Chandra X-ray Observatory (NASA) The flagship US x-ray observatory today. Launched July 23, 1999.
• XMM-Newton (ESA) The X-ray Multi-Mirror satellite is Europe's flagship x-ray observatory. Launched: December 10, 1999.
• RXTE The Rossi X-ray Timing Explorer is an x-ray telescope dedicated to making observations with time resolutions of a thousandth of a second or better. Launched: December 30, 1995.
• Astro-E2/Suzaku This satellite is the latest Japanese x-ray observatory. It is designed for high-resolution spectroscopy. Launched: July 10, 2005.
• INTEGRAL (ESA) The INTErnational Gamma-Ray Astrophysics Laboratory is the most sensitive gamma-ray observatory ever launched. Launched: October 16, 2002.
• SWIFT A medium-class Explorer satellite that studies gamma-ray bursts at gamma-ray, x-ray, ultraviolet, and visible wavelengths. Launched: November 20, 2004.
• AGILE A small satellite to produce simultaneous images in gamma rays and hard x-rays. Also has good time resolution. Launched: April 23, 2007

Past High Energy Astronomical Observatories

• HETE-2 The High Energy Transient Explorer was a small scientific satellite designed to detect and localize gamma-ray bursts. Launched: October 9, 2000.
• Major Milestones in X-ray Astronomy

Active Ultraviolet Telescopes

• FUSE -- Far Ultraviolet Spectroscopic Explorer (NASA). Performs high-resolution spectroscopy in the far-ultraviolet spectral region. Launched: June 24, 1999. (satellite died in August 2007)
• GALEX Galaxy Evolution Explorer (NASA). Launched: April 28, 2003.

Revised September 19, 2007