6.1 DATA ANALYSIS

Over the years NASA has supported the analysis of archival data from past and existing missions. This research opportunity has served to extract important science from data sets that have had only limited initial analyses. Given the great cost of developing and launching spacecraft-based instruments, this is a cost effective method of doing science-on a par with keeping existing missions operating. This avenue takes on new importance in this age of declining resources. Further, with the modern multiwavelength approach to understanding high-energy sources, continued observation and discovery at other wavelengths makes correlative studies of archival space data an essential astrophysics tool. Finally, new numerical and statistical techniques are continually developed; examination of archival data provides new discoveries and improved guidelines for new observations and new missions. These scientific rationales argue for a vigorous and adequately funded program of long-term archival data analysis. Strong arguments for continued archival research also stem from the need to preserve human capital. The focused effort of the 1980's and early 1990's to develop the CGRO mission has resulted in a strong scientific community and important connections with other wavelengths. Because major mission opportunities like CGRO are rare, it is essential to support continued data analysis to maintain a stable intellectual infrastructure in the upcoming period when few new missions are anticipated. Young scientists developing future mission hardware need contact with gamma-ray data to balance their training while researchers in other fields will maintain active connections with high energy problems through the study of the the wealth of data produced by CGRO and other recent missions. Such efforts position the community for an effective use of the major new missions planned for the next decade.

6.2 THEORY

Gamma-ray observations probe exotic physics from remarkable, energetic sources. However, the nonthermal nature of the emission, the modest photon statistics and the need to connect the high-energy radiations with lower energy observations makes progress in the field particularly dependent on adequate theoretical support. In turn the puzzles posed by high-energy observations have spurred a ferment of theoretical activity, as exemplified by the continuing stream of papers on gamma-ray burst models. As discussed earlier, many CGRO observations remain unexplained. Late in the CGRO era, support for theoretical work on high-energy problems is becoming very limited. The NASA theory program plays an important role, but experiences extreme pressure from other disciplines. Because new understanding spurred by CGRO and other recent missions offers hope of important advances in our understanding of compact objects and other high-energy sources, expanded support of theoretical work in this area can provide important progress in the post-CGRO era. It will also be important to continue to refine theoretical predictions, looking forward to the sensitive observational tests of future missions.