in some of the key reactions. New work with radioactive targets has also provided information on several reactions that occur during explosive burning where unstable nuclei can play a role.
Measurements of certain isotopic anomalies have also shed light on the origin of the solar system and the role of certain nuclear processes during nucleosynthesis. Detailed measurements of beta-decay strength functions for nuclei far from stability has allowed a better understanding of the path of nucleosynthesis as it approaches both the proton and neutron drip line.
In the particle physics realm, constraints on the possible modifications to the standard model of the strong and electroweak interactions, as well as better understanding of particle properties, have contributed significantly to astrophysics in the last decade. New data from SLAC and CERN has provided strong confirmation of the standard model, with the discovery of the W and Zo particles. And very recently, the detailed measurements of the Zo decay have constrained the number of possible generations (limiting any additional new quarks and leptons) to three, in excellent agreement with the bounds obtained from big bang nucleosynthesis. New high precision measurements of the free neutron lifetime have significantly reduced several key astrophysical uncertainties. These new measurements (some using advanced neutron storage-bottle technology) have direct bearing on the predictions from the standard big bang and on the rate of the p-p reaction in the solar model.
Some of the recommendations of the Field Committee Report related to Theory and Laboratory Astrophysics have been implemented, but there has been little response to others. In general, we give higher marks to NASA than to the NSF in effectively responding to the Field Committee recommendations.
NASA has significantly increased its support of theoretical astrophysics through the Astrophysical Theory Program. This program has strengthened or catalyzed the formation of several research groups and supported a significant number of postdoctoral research associates and graduate students. The NASA Graduate Student Researchers Program has also supported a number of students working in theoretical or laboratory astrophysics. We consider this program to be highly successful.
The most significant positive development related to NSF funding is the Presidential Young Investigators program. The recipients of these awards seem to be able to ramp up to a high level of activity more quickly than investigators without these awards, and they are competitive in seeking NSF support once their PYI funding has ended.
Unfortunately, theoretical and laboratory astrophysics have not fared well within the general NSF astronomy grants program. Far from the 50% increase recommended by the Field Committee, these areas have actually lost ground. The fraction of the NSF astronomy budget going into Theory is about 1/3 the fraction going into Theory in NSF Physics. Despite the recommendation of the Theory subpanel that Theoretical Astrophysics be set up as a separate program in the Astronomy Division, similar to Theoretical Physics in the Physics Division, theory remains balkanized among different programs, to the perceived detriment of researchers who are oriented towards general physical processes rather than towards specific astronomical objects.
The DOE laboratories have made some progress in supporting work related to astrophysics, but much remains to be done in the DOE supported areas of atomic and molecular, nuclear, particle, and plasma physics as it relates to astrophysics. Support for theoretical astrophysics at the National Astronomy Centers is essentially nil, with the laudable exception of the NASA-funded Space Telescope Science Institute. The NSF Astronomy Centers seem to have ignored the Field Committee recommendations.
Advanced computing has been supported by the NSF and DOE, and most researchers now have greatly improved opportunities for large scale scientific computing. However, the strong support for supercomputer facilities has not been matched by support for more modest facilities at the individual, group or departmental level. This is unfortunate for several reasons: first, the smaller machines are far more cost-effective for many tasks than supercomputers, and in some cases now actually approach the supercomputers in speed; a second reason is that the solutions of many problems in astrophysics are more limited by lack of imagination than lack of computation, so that it is especially important to provide flexible, friendly and accessible local computing that permits working theorists to solve small and medium scale computational problems with a minimum of