1. JD1 rationale Catherine Cesarsky, Diego Torres, Stefan Wagner

2. The Highest-Energy Gamma-Ray Universe observed with Cherenkov Telescope Arrays The purpose of JD 1 is to discuss the highest-energy gamma- ray universe as observed with Cherenkov telescope arrays with particular focus on the fruitful scientific interactions of such arrays and their capabilities with the broad astronomical community. This exchange will help to refine and prepare the science goals and science optimization of the instrument as well as user interfaces and user services that would allow the best scientific exploitation of the array by the largest possible astronomical community.

3. Monday August 20 10.30-18.00 Results from current generation Cherenkov telescopes Prospects: CTA, LHASSO, HAWC Prospective science High resolution optical astronomy with Cherenkov arrays Multiwavelength context: X rays

4. Tuesday August 21 10.30-12.30 Multiwavelength context: radio, infrared Prospective science General discussion: Evolution of gamma ray astronomy questions, interventions or points for debate: to me, at the meeting, or by e mail: catherine.cesarsky@cea.fr

5. Possible topics for general discussion More on science themes : e.g. Studies of the physics of galactic particle accelerators, such as pulsars and pulsar wind nebulae, supernova remnants, and gamma-ray binaries; cumulative effects seen at various scales, from massive star forming regions to normal to starburst galaxies; gas accretion. Particle acceleration near super-massive black holes: blazars, radio galaxies and other classes of AGN that can potentially be studied in high-energy gamma rays; interacting galaxies; extragalactic background light (EBL), galaxy clusters, Gamma Ray Burst (GRB). “New physics”, with searches for dark matter through possible annihilation signatures, tests of Lorentz invariance, and any other observational signatures that may challenge our current understanding of fundamental physics. More on synergies with facilities at other wavelengths More on requirements on the facility and its exploitation