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By facillitating multiwavelength observations of AGNs, we aim to improve the temporal density and overlap of observations and to increase the baseline. Coordinated gamma-ray/x-ray/UV/optical/IR/Radio observations have helped to provide constraints on the physical conditions in AGN jets by providing information about a new spectral component. Ultimately, when the radiation mechanisms and physical parameters are better understood, we hope to make progress in understanding the energetics of the central engine. Once this is done, we can better use these calibrated sources as probes of the intervening radiation fields (the diffuse extragalacti background radiation) and as probes of Lorentz Invariance and the structure of spacetime.

Similar gains are expected from multiwavelength observations of GRBs. EGRET observations have shown delayed emission at as much as 20 GeV, showing promise for ground-based gamma-ray observations. Compared with satellite experiments, ground-based instruments will have 10^4 times the effective area, the most important factor for observations of very short signal dominated events. Again, the VHE observations will provide new constraints on the inverse-Compton component providing information about the external shock (and, in the case of prompt detection, of the internal shock as well). While the fireball mechanism is now well established, the nature of the progenitor is unknown. The VHE observations might be able to discriminate between the wind environment of a hypernova compared with the lower ambient ISM density surrounding a neutron star merger.

The short variability timescales in the gamma-ray regime imply that this emission comes from a compact region near the base of the jet. If the high energy emission originates from inverse-Compton, the X-ray to gamma-ray Spectral energy distributions can be most naturally explained with very high Doppler factors (20-100) and small magnetic fields (<0.1G). If on the other hand, proton Pair-induced cascades (or Proton synchrotron) models explain the VHE emission then we anticipate much higher magnetic fields. Combining the VHE data from ground-based experiments, the MeV-GeV data from GLAST and the X-ray data should provide a sensitive discriminant between these competing models.