This volume is the first of its kind on focusing gamma-ray telescopes. Forty-eight refereed papers provide a comprehensive overview of the scientific potential and technical challenges of this nascent tool for nuclear astrophysics. The book features articles dealing with pivotal technologies such as grazing incident mirrors, multilayer coatings, Laue- and Fresnel-lenses - and even an optic using the curvature of space-time.
HESS (High Energy Stereoscopic System), a ground-based Cerenkov array telescopes has been operated since a few years and in 2004 has performed the ?rst Galactic plane scan with a sensitivity of a few percent of the Crab at energies above 100 GeV, resulting in the discoveryofeightsources,mostofwhichwithoutanycounterpartatdifferentenergies[1,2]. ParticularattentionwasdevotedtoHESSJ1813-178,notidenti?edwithanyknownX/gamma ray emitter and hypothesised to be a dark particle accelerator. Independently, and at the same time, INTEGRAL discovered a new soft gamma-ray source, namely IGR J18135-1751, identi?edasthecounterpartofHESSJ1813-178.Thishighenergyemitter,whosenaturewas still mysterious at the time of the discovery was then associated with the supernova remnant (SNR) G12.82 0.02 [6, 10, 18]. Even if a chance coincidence cannot be completely ruled out in view of the 2 arcmin INTEGRAL error box and the possible angular extension in the high energy,theoverallcharacteristicsofthisstarformingregion[7]comprisingSNRG12.82 0.02 areconsistentwithsupernova/plerionorigin.Morerecently,theMAGIC(MajorAtmospheric Gamma Imaging Cerenkov telescope) collaboration has reported a positive observations of HESSJ1813178,resultinginagamma-ray?uxconsistentwiththepreviousHESSdetection and showing a hard power law with? = 2.1 in the range from 0.410TeV [3].Scientific Requirements and Prospects.- Prospects in space-based gamma-ray astronomy.- Annihilation of positrons in the Galaxy.- Prospects and requirements for measurements of extragalactic ?-ray lines.- lĂ7