2007/10/31 by R. A. Osten, Rachel A. Osten, T. S. Bastian · 70 citations
Physics and Astronomy · #Afterglow #Astro and Planetary Science #Astronomy #Astrophysics #Flare #Flare star #Gamma-ray burst #Ionosphere and magnetosphere dynamics #Maser #Physics #Radio telescope #Solar and Space Plasma Dynamics #Spectral line #Spectral resolution #Stars #T Tauri star #astro-ph
paper · pdf · doi:10.1086/525013
published in The Astrophysical Journal 674(2), 1078-1085 (IOP Publishing) · 24 pages, 8 figures, accepted for publication in the Astrophysical Journal. figures degraded to fit size requirements of astro-ph
arxiv created 2007/10/31 · openalex publication_date 2008/02/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report observations of a radio burst that occurred on the flare star AD Leonis over a frequency range of 1120-1620 MHz (λ ≈ 18–27 cm). These observations, made by the 305 m telescope of the Arecibo Observatory, are unique in providing the highest time resolution (1 ms) and broadest spectral coverage (Δ ν/ν = 0.36) of a stellar radio burst yet obtained. The burst was observed on 2005 April 9. It produced a peak flux density of ~500 mJy, and it was essentially 100% right-circularly polarized. The dynamic spectrum shows a rich variety of structure: patchy emission, diffuse bands, and narrowband, fast-drift striae. Focusing our attention on the fast-drift striae, we consider the possible role of dispersion, and find that it requires rather special conditions in the source to be a significant factor. We suggest that the emission may be due to the cyclotron maser instability, a mechanism known to occur in planetary magnetospheres. We briefly explore possible implications of this possibility.