Formation and Signatures of the First Stars
Abstract
Description
We use a spherical hydrodynamics code to show that in cold dark matter cosmologies, the first stars form at z=50 through the direct collapse of gas in low-mass systems (approx 10^4 solar masses). Photons from the first stars easily photodissociate the molecular hydrogen throughout the universe and so molecular cooling does not affect the subsequent fragmentation of gas clouds into stars. We examine observable signatures of the pre-galactic population of stars. These include the detected metallicity and photo-ionization of the intergalactic medium, and the soon to be detected damping of microwave anisotropies on small angular scales (< 10 degrees). The Next Generation Space Telescope will be able to directly image the pre-galactic star clusters, while the DIMES experiment could detect their Bremsstrahlung emission.
3 pages LaTex, no figures. To appear in the Proceedings of the 18th Texas Symposium on Relativistic Astrophysics, Chicago, December 1996, eds. A. Olinto, J. Frieman and D. Schramm, (World Scientific)
3 pages LaTex, no figures. To appear in the Proceedings of the 18th Texas Symposium on Relativistic Astrophysics, Chicago, December 1996, eds. A. Olinto, J. Frieman and D. Schramm, (World Scientific)