Observation of Ultrahigh-Energy Cosmic Rays with the ANITA Balloon-Borne Radio Interferometer

• Main Authors: Hoover, S, Nam, J, Gorham, PW, Grashorn, E, Allison, P, Barwick, SW, Beatty, JJ, Belov, K, Besson, DZ, Binns, WR, Chen, C, Chen, P, Clem, JM, Connolly, A, Dowkontt, PF, DuVernois, MA, Field, RC, Goldstein, D, Vieregg, AG, Hast, C, Israel, MH, Javaid, A, Kowalski, J, Learned, JG, Liewer, KM, Link, JT, Lusczek, E, Matsuno, S, Mercurio, BC, Miki, C, Miocinovic, P, Naudet, CJ, Ng, J, Nichol, RJ, Palladino, K, Reil, K, Romero-Wolf, A, Rosen, M, Ruckman, L, Saltzberg, D, Seckel, D, Varner, GS, Walz, D, Wu, F
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER PHYSICAL SOC 2010
• Subjects: EXTENSIVE AIR SHOWERS; PULSES; EMISSION; SPECTRUM; Antarctic; The Antarctic; Antarc*
• Online Access: https://discovery.ucl.ac.uk/id/eprint/408812/1/408812.pdf; https://discovery.ucl.ac.uk/id/eprint/408812/

We report the observation of 16 cosmic ray events with a 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 measurements in the 300-900 MHz range, which are the first self-triggered, first ultrawide band, first far-field, and the highest energy sample of cosmic ray events collected with the radio technique. Their properties are inconsistent with current ground-based geosynchrotron models. The emission is 100% polarized in the plane perpendicular to the projected geomagnetic field. Fourteen 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. Based on a likelihood analysis, we estimate angular pointing precision of order 2 degrees for the event arrival directions.