69052 - High Energy Astrophysics

Learning outcomes

This course focuses on the high-energy (X-ray and Gamma-ray) emission from populations of Galactic and extra-galactic sources.

The student is expected to attain a good knowledge of the techniques related to the detection of X-ray and Gamma-ray photons and on the properties of past and present X-ray telescopes. Students will be able to critically discuss the high-energy emission properties
of compact X-ray sources, mostly X-ray binaries and Active Galactic Nuclei (AGN), and extended X-ray sources, with particular emphasis on the Galactic Center region. Through a multi-wavelength approach, students will relate the X-ray properties of AGN with their emission at other wavelengths; they will also study the AGN contribution to the cosmic X-ray background.

Course contents

INTRODUCTION TO HIGH-ENERGY ASTROPHYSICS

• Detection techniques for high-energy photons. X-ray and Gamma-ray detectors; CCDs in X-rays. Wolter-type telescopes and coded-aperture masks.

• History of the high-energy Astronomy. Excursus on the properties of the main X-ray/Gamma-ray satellites of the 'golden age'.

• Hints on emission mechanisms: blackbody/bremsstrahlung/synchrotron/Compton scattering and Inverse Compton scattering, and some examples in the field of high-energy Astrophysics. Line production; collisional and ionization equilibrium.

GALACTIC X-RAY ASTRONOMY

• X-ray emission from Solar System objects.

• Stellar X-ray Astronomy: main-sequence (MS) and pre-MS stars/very low-mass stars.

• White dwarfs, cataclysmic variables, novae, pulsars, pulsar wind nebulae, and neutron stars.

• X-ray binaries: classification and physical properties.

• The Galactic Center: a multi-wavelength perspective. Emission from point-like and extended X-ray/Gamma-ray sources. Properties of the Fermi bubbles. Matter infalling onto SgrA*. 

EXTRA-GALACTIC X-RAY ASTRONOMY

• Clusters of galaxies.

• Ultraluminous X-ray sources

• Active Galactic Nuclei (AGN): X-ray spectral components in X-rays: models vs. observations. AGN multi-wavelength properties and classification.

• Hints on Unified Model of AGN.

• X-ray surveys in the last decade. AGN contribution to the cosmic X-ray background. Open issues.

• High-redshift AGN: detection and multi-wavelength properties.

Readings/Bibliography

• J. Trumper & G. Hasinger: "The Universe in X-rays", Astronomy & Astrophysics Library, Springer
  

• Frederick D. Seward, Philip A. Charles: "Exploring the X-ray Universe", Cambridge University Press
  

• Glenn F. Knoll: "Radiation Detectors for X-Ray and Gamma-Ray Spectroscopy", Third Edition (2000), John Wiley & Sons
  

• Hale Bradt: "Astronomy Methods", Cambridge University Press
  

• Hale Bradt: "Astrophysics Processes: The Physics Of Astronomical Phenomena", Cambridge University Press
  

• George B. Rybicky, Alan P. Lightman: "Radiative Processes in Astrophysics", Wiley
  

• S.M. Kahn, P. von Ballmoos, R.A. Sunyaev: "High-Energy Spectroscopic Astrophysics", Springer
  

• Malcolm S. Longair: "High-Energy Astrophysics", Cambridge University Press
  

• Fulvio Melia: "High-Energy Astrophysics", Princeton University Press
  

• Bradley M. Peterson: "An introduction to Active Galactic Nuclei", Cambridge University Press
  

• J. Frank, A. King & D. Raine: "Accretion Power in Astrophysics", Cambridge University Press
  

• Walter H.G. Lewin, Michiel van der Klis: "Compact Stellar X-ray Sources", Cambridge Astrophysics Series, 39
  
• Keith Arnaud, Randall Smith, Aneta Siemiginowska: "Handbook of X-ray astronomy", Cambridge Observing Handbooks for Research Astronomers 
• Gabriele Ghisellini: "Radiative processes in high energy astrophysics", Springer, Lecture Notes in Physics 873
• Anil K. Pradhan & Sultana N. Nahar: "Compact Stellar X-ray Sources", Atomic Astrophysics and Spectroscopy", Cambridge University Press
• Hagai Netzer: "The Physics and Evolution of Active Galactic Nuclei", Cambridge University Press

plus relevant literature papers (shown on my personal web page).

Teaching methods

Oral lectures. During lessons, all the problems related to the detection of high-energy emission from cosmic sources and their emission mechanisms will be deeply investigated using textbooks and recent articles and reviews from literature.

Assessment methods

Oral exam, starting from a topic chosen by the student. The oral exam will comprise questions on X-ray/Gamma-ray instruments, on emission mechanisms, and on Galactic and extra-galactic topics. It is mandatory that the student is able to link, in the most appropriate way, the various topics discussed during the course, in particular the high-energy emission of the classes of X-ray sources with the emission mechanisms discussed at the beginning of the course. The candidate should demonstrate the capability of discussing in a critical way the main problems and open issues of modern high-energy astrophysics, and skill of deriving physical quantities for X-ray sources.

Teaching tools

Powerpoint presentations (available on my personal Unibo web page) and blackboard.

Office hours

See the website of Cristian Vignali