ROME III. The Arecibo Search for Star-Planet Interactions at 5 GHz

Abstract: After nearly three decades of discovery, many exoplanetary systems have been studied and characterized in detail with one important exception: exoplanet magnetism. Although many surveys sought to detect magnetospheric radio emissions from exoplanets to directly measure their magnetic field strengths, they have yet to reveal an unambiguous detection. However, the indirect detection of exoplanet magnetic fields by measuring their influence on their host stars via magnetic star-planet interactions has recently gained prominence as an alternative method of discovery. This third paper of the ROME (Radio Observations of Magnetized Exoplanets) series presents the results of a targeted radio survey of eight nearby exoplanet-hosting systems that may engage in star-planet interactions. This survey, conducted with the Arecibo radio telescope at $\sim$5 GHz, has the greatest frequency coverage of any to date, while providing mJy-level sensitivity over $<$1 s integration times. No exoplanet-induced stellar radio bursts were detected. The orbital phase coverage of candidate systems for magnetic star-planet interactions is described, and the survey results are examined within the context of the plasma flow-obstacle paradigm and searches for star-planet interactions at other wavelengths.