Observational Astrophysics on Milli-, Micro-, and Nanosecond Timescales

Abstract

Instrumentation and observing methods are being developed for a program in optical high-speed astrophysics, an exploratory project entering the domains of milli-, micro-, and nanosecond variability. Current studies include accretion flows around compact objects, stellar scintillation, and astronomical quantum optics. To study such rapid phenomena is not possible everywhere in the spectrum (e.g., X-ray studies are constrained by the photon count rates feasible with current spacecraft). The ground-based optical is a promising region, for which we have constructed a dedicated instrument, QVANTOS (‘Quantum-Optical Spectrometer’). Its first version was used on La Palma to study atmospheric scintillation on timescales between 100 milli-and 100 nanoseconds. For very high time resolution, light curves are of little use, and statistical functions of variability have to be measured. The noise in such functions decreases dramatically with increased light collecting power, making very large telescopes much more sensitive for the study of rapid variability than 2–4m class ones.