This lecture gives a comprehensive overview of the instrumentation that is employed in the field of gamma-ray astronomy.It describes the principal physical processes, detector technologies, and telescope configurations that are used in this field.Special emphasis is given to the instrumentation of the upcoming INTEGRAL observatory.The lecture closes with a brief summary of currently available and planned gamma-ray instruments.

Compact objects, the ultimate stage of evolution of massive stars, are strongX- and gamma-ray emitters. The compact object (white dwarf, neutronstar, or black hole) accretes matter and electromagnetic fields fromthe close environment. During this process, a part of the gravitational potential energy is reprocessed into kinetic energy in the magnetised fluid. The interplay of turbulence and/or shock generation allows a fraction of this energy to be transfered to a tiny supra-thermal particle population and ultimately to be radiated away into high energy photons. The radiation can be produced in a limited number of ways: cyclo-synchrotron and bremsstrahlung processes; the Compton effect; nuclear interactions and pair creation/absorption. This lecture presents the main properties of the aforementioned mechanisms and illustrates them in some astrophysical situations.

This chapter is intended to provide a general presentation of the atomic andnuclear processes responsible for X-ray line and gamma-ray line emission invarious astrophysical environments. I consider line production from hotplasmas, from accelerated particle interactions, from the decay ofradioactive nuclei synthesized in stars and from positron annihilation.Spectroscopic properties of these emissions are discussed in the light ofthe detection capabilities of modern space instruments.

Spectral analysis is the main tool of astrophysical research.Current instrumental technology offers very sensitive CCD detectorswith enough spectral resolution for many purposes.This introductory text is aimed at graduate students starting a thesisin X-ray astronomy, and at non-specialists who wish to analyseX-ray data themselves. It gives the basic tools and explains the basicissues often implicit in specialised papers. X-ray spectroscopy differs from spectroscopy at longer wavelengths because it is photon based with relatively small numbers ofphotons. As a result the Poisson process is at the core of thestatistical description of X-ray spectra. The classicalmodel-fitting procedure is described and illustrated on a detailedexample. It is applicable to any parametric model and anyinstrumental data. High resolution X-ray spectroscopy, now applicable to many sourcesthanks to sensitive grating instruments, allows to measure individuallines accurately. The diagnostics that it offers are very similarto those offered by mid-resolution optical spectroscopy:line ratios, line broadening, absorption lines.

This course reviews our present knowledge about the physicalprocesses behind the supernovae explosions, stressing the difficultiesencountered in the quest to describe the latter quantitatively.

This lecture gives an introduction to the topic of supernova nucleosynthesis which is at the origin of almost all nuclear species that we encounter in the Universe.It starts with an overview over the relevant nuclear physics, with some emphasise on nuclear stability and nuclear reactions.The central part of the lecture is devoted to the synthesis of new elements in the interiors of stars, either during their quiescent live or during their violent explosion as supernova.The different types of supernova explosions are exposed and their key nucleosynthesis products are summarised.The lecture closes with an overview over gamma-ray line diagnostics which provides a modern tool to study supernova nucleosynthesis by the measurement of freshly produced radioactive isotopes.

This text is aimed at presenting the basic ingredients necessaryto understand shell-type supernova remnants, with particularemphasis on their X-ray emission.The other observational domains (radio and optical) are mentionedbut not discussed in depth.I do not discuss at all the synchrotron nebulae, such as the Crab Nebula,which are also relics of a supernova explosion, but are driven bythe remaining pulsar rather than the mechanical energy of the supernova.After a brief historical introduction, I describe the hydrodynamicconcepts used for supernova remnants. Then I describe the Sedov modelgoverning middle-aged supernova remnants, and the coronal conditionsunder which the X-ray emission is computed.Quantitative formulae are given for the Sedov model,allowing to relate X-ray observations to energy, ambient density and age.A chapter describes the initial (young) and final (old) stagesof supernova remnants.Cosmic-ray acceleration at shocks is described, as well as itsconsequences on supernova remnants. The final chapter dealswith statistical issues.

Theoretical models of the equation of state (EOS)of neutron-star matter (starting with the crustand ending at the densest region of the stellar core) are reviewed. Apart froma broad set of baryonic EOSs, strange quark matter, and even more exotic (abnormaland Q-matter) EOSs are considered. Results of calculations of Mmaxfor non-rotating neutron stars and exotic compact stars are reviewed, withparticular emphasis on the dependence on the dense-matter EOS. Rapid rotationincreases Mmax, and this effect is studied for both neutron stars and exoticstars. Theoretical results are then confronted with measurements of masses of neutronstars in binaries, and the consequences of such a confrontation and their possible impacton the theory of dense matter are discussed.

Accretion onto a compact object must occur through a disc when thematerial has some initial angular momentum. Thin discs and the thickerlow radiative efficiency accretion flows (LRAFs) are solutionsto this problem that have been widely studied and applied. This is anintroduction to these accretion flows within the context of X-raybinaries and cataclysmic variables.

This lecture reviews in simple terms the general subject of large scale magnetic field coupling to plasma flowsin the vicinity of accreting compact stars. The relevant astrophysical phenomenology is summarized.Disk interaction with the magnetosphere ofaccreting stars is first discussed, in particularthe structure of the magnetopause, its stabilityand plasma ejection in so-called propeller systems. The physics of accretion/ejection is then considered. Acceleration and focusing mechanisms ofjets from accretion disks around compact stars or black holes and the question of the self-consistency of accretion and ejection are described. By contrast, small scale MHD turbulence in disks is not discussed, neither are accretion columns near thepolar caps of neutron stars or white dwarfs. The reader is only assumed to have some basic knowledge ofastrophysics and of fluid mechanics and electromagnetism.