HEAD 2000, November 2000
Session 39. The Future of X-Ray Timing
Invited Workshop, Thursday, November 9, 2000, 7:30-10:00pm, Pago Pago Ballroom

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[39.13] The Scientific Promise of Sensitive All-sky Monitors

W. C. Priedhorsky (Los Alamos National Laboratory), G. W. Fraser (Leicester University), K. N. Borozdin (Los Alamos National Laboratory), V. A. Arefiev (Space Research Institute Moscow)

X-Ray All-Sky Monitors (ASMs) have become indispensable for astronomers. ASMs track changes in the highly variable X-ray sky, enabling otherwise impossible observations. But previous ASMs have given us only a glimpse of the rich variability of the X-ray sky on timescales less than a day, and have been limited in sensitivity to the level achieved by pointed instruments in the early 1970's. They lack sensitivity to faint and fast-changing sources.

The sensitivity limitation can be overcome by focusing x-ray optics based on the configuration of the lobster's eye, which offers at least an order of magnitude improvement over non-focusing technologies. Even without focusing, on-board processing and real-time data links can open our eyes to fast phenomena in the x-ray sky, such as the ubiquitous x-ray flashes. We discuss the Skywatcher and Lobster instrument concepts for the International Space Station, which capitalize on these technologies.

These instruments would allow the immediate reporting of fast phenomena, and let us understand the relationship of x-ray flashes to gamma-ray bursts. Accurate flash positions from Skywatcher will enable rapid multi-wavelength observations of flash counterparts, essential for understanding the physics of the progenitors. Taking advantage of focusing optics, Lobster would boost the sensitivity of all-sky X-ray monitors by an order of magnitude and open a new decade of the soft X-ray band to continuous monitoring. With its large improvement in sensitivity, Lobster would allow the continuous monitoring of all classes of x-ray source, including cataclysmic variables, late-type stars, and pre-main sequence stars. It would provide the first true census of time variability in active galactic nuclei.

The author(s) of this abstract have provided an email address for comments about the abstract: wpriedhorsky@lanl.gov

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