2012/03/20 by J. F. Dolan, Dolan, J. F.
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Laser-Plasma Interactions and Diagnostics #Particle Accelerators and Free-Electron Lasers #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.1203.4616
arxiv created 2012/03/20 · openalex publication_date 2012/03/20 · arxiv updated 2012/03/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
X-ray pulses with millisecond-long FWHM have been detected in RXTE (Rossi X-Ray Timing Explorer) observations of Cyg X-1. Their identity as short-timescale variations in the X-ray luminosity of the source, and not stochastic variability in the X-ray flux, is established by their simultaneous occurrence and similar pulse structure in two independent energy bandpasses. The light-time distance corresponding to the timescale of their FWHM indicates that they originate in the inner region of the accretion disk around the system's black hole component. The fluence in the pulses can equal or exceed the fluence of the system's average continuous flux over the duration of the pulses' FWHM in several different bandpasses between 1 and 73 keV. Millisecond pulses are detected during both high and low luminosity states of Cyg X-1, and during transitions between luminosity states.