9714627 Bhattacharjee Description: This is a U.S.-India research collaboration entitled Phase Transitions in the Early Universe and Probes of Large Scale Distribution of Matter in the Universe. This project will build on a joint program in theoretical astrophysics developed in 1987 thru 1992 between the University of Chicago and the Tata Institute of Fundamental Research (TIFR). The current project is under the direction of David Schramm, University of Chicago and Pijushpani Bhattacharjee, Indian Institute of Astrophysics (IIA), Bangalore. These nodel institutions will serve as organizational centers rather than sole research venues for the participants. The research will build on the earlier effort which in the beginning had a natural focus on the Supernovae, and later on the role of the quark-hadron phase transition in the early universe and ultra high energy cosmic ray interactions. The current objectives will be to work out cosmological and astrophysical implications of phase transitions in the early universe, particularly the implications of topological defects and electroweak baryogenesis; and to study the phase space distribution of dark matter in the Galaxy and the phenomenon of gravitational lensing as a probe of large-scale distribution of dark matter in the universe. Scope: This collaboration is an outgrowth of a joint research program among several of the most distinguished astrophysicists in the US and India. The output was most impressive including the pioneering work by the Indian PI. This award will support several short-term visits by Indian coPIs and postdocs, as well as visits to India by the US PI. In addition to the advances in fundamental knowledge expected from the research, the exchange of ideas with Indian leaders of cosmology will be valuable for the US scientific community. ***
