APS Neutrino Study: Report of the neutrino astrophysics and cosmology working group

In 2002, Ray Davis and Masatoshi Koshiba were awarded the Nobel Prize in Physics 'for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos'. However, while astronomy has undergone a revolution in understanding by synthesizing data taken at many wavelengths, the universe has only barely been glimpsed in neutrinos, just the Sun and the nearby SN 1987A. An entire universe awaits, and since neutrinos can probe astrophysical objects at densities, energies, and distances that are otherwise inaccessible, the results are expected to be particularly exciting. Similarly, the revolution in quantitative cosmology has heightened the need for very precise tests that depend on the effects of neutrinos, and prominent among them is the search for the effects of neutrino mass, since neutrinos are a small but known component of the dark matter. In this report, we highlight some of the key opportunities for progress in neutrino astrophysics and cosmology, and the implications for other areas of physics.