title: Circular Polarizations of Gravitational Waves from Core-Collapse Supernovae: A Clear Indication of Rapid Rotation.
abstract: We propose to employ the circular polarization of gravitational waves emitted by core-collapse supernovae as an unequivocal indication of rapid rotation deep in their cores just prior to collapse. It has been demonstrated by three dimensional simulations that nonaxisymmetric accretion flows may develop spontaneously via hydrodynamical instabilities in the postbounce cores. It is not surprising, then, that the gravitational waves emitted by such fluid motions are circularly polarized. We show, in this Letter, that a network of the second generation detectors of gravitational waves worldwide may be able to detect such polarizations up to the opposite side of the Galaxy as long as the rotation period of the core is shorter than a few seconds prior to collapse.
authors.affiliation: KAGRA Observatory, Institute for Cosmic Ray Research, University of Tokyo, 238 Higashi Mozumi, Kamioka, Hida, Gifu 506-1205, Japan.|Gravitational Wave Project Office, National Astronomical Observatory of Japan, 2-21-1, Osawa, Mitaka, Tokyo 181-8588, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hayama
authors.affiliation: Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland.
authors.forename: Takami
authors.initials: T
authors.lastname: Kuroda
authors.affiliation: Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Ko
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Advanced Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.|Department of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan.
authors.forename: Shoichi
authors.initials: S
authors.lastname: Yamada