Observation of Ultra-high-energy Cosmic Rays with the ANITA Balloon-borne Radio Interferometer

• Main Authors: Hoover, S., Nam, J., Gorham, P. W., Grashorn, E., Allison, P., Barwick, S. W., Beatty, J. J., Belov, K., Besson, D. Z., Binns, W. R., Chen, C., Chen, P., Clem, J. M., Connolly, A., Dowkontt, P. F., DuVernois, M. A., Field, R. C., Goldstein, D., Vieregg, A. G., Hast, C., Hebert, C. L., Israel, M. H., Javaid, A., Kowalski, J., Learned, J. G., Liewer, K. M., Link, J. T., Lusczek, E., Matsuno, S., Mercurio, B. C., Miki, C., Miočinović, P., Naudet, C. J., Ng, J., Nichol, R. J., Palladino, K., Reil, K., Romero-Wolf, A., Rosen, M., Ruckman, L., Saltzberg, D., Seckel, D., Varner, G. S., Walz, D., Wu, F.
• Format: Text
• Language: unknown
• Published: arXiv 2010
• Subjects: High Energy Astrophysical Phenomena astro-ph.HE; Instrumentation and Methods for Astrophysics astro-ph.IM; FOS Physical sciences; Antarctic; The Antarctic; Antarc*
• Online Access: https://dx.doi.org/10.48550/arxiv.1005.0035; https://arxiv.org/abs/1005.0035

We report the observation of sixteen cosmic ray events of mean energy of 1.5 x 10^{19} eV, via radio pulses originating from the interaction of the cosmic ray air shower with the Antarctic geomagnetic field, a process known as geosynchrotron emission. We present the first ultra-wideband, far-field measurements of the radio spectral density of geosynchrotron emission in the range from 300-1000 MHz. The emission is 100% linearly polarized in the plane perpendicular to the projected geomagnetic field. Fourteen of our observed events are seen to have a phase-inversion due to reflection of the radio beam off the ice surface, and two additional events are seen directly from above the horizon. : 5 pages, 5 figures, new figure added