2001/02/12 by H. C. Lee, Hyong C. Lee, R. Misra +2 · 62 citations
Physics and Astronomy · #Amplitude #Compton scattering #Energy (signal processing) #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research #Oscillation (cell signaling) #Photon #Photon energy #Plasma #Soft photon #Solar and Space Plasma Dynamics #astro-ph
paper · pdf · doi:10.1086/319171
published in The Astrophysical Journal 549(2), L229-L232 (IOP Publishing) · 4 pages, 2 figures
arxiv created 2001/02/12 · openalex publication_date 2001/03/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
An empirical Compton upscattering model is described that reproduces both the fractional amplitude (rms) versus energy and the soft time lags in the ≈830 Hz quasi-periodic oscillation (QPO) observed in 4U 1608-52 on 1996 March 3. A combination of two coherent variations in the coronal and soft photon temperatures (with their relative contributions determined by enforcing energy conservation) gives rise to the QPO's energy-dependent characteristics. All input parameters to the model, save a characteristic plasma size and the fraction of Comptonized photons impinging on the soft photon source, are derived from the time-averaged photon energy spectrum of the same observation. Fits to the fractional rms and phase lag data for this kilohertz QPO imply that the spatial extent of the plasma is in the range from ~4 to 15 km.