The Spin-X wide-field X-ray monitor of the Spectrum-X-Gamma astrophysical observatory

• Published in: Astronomy letters 2000-12, Vol.26 (12), p.779-787
• Main Authors: Pavlinsky, M N, Grebenev, S A, Mazov, P A, Dekhanov, I A, Ryvkin, D B, Sunyaev, R A, Surtaev, V I, Mokrousov, N V, Glushenko, A G, Yampol'skii, S I, Novikov, A D
• Format: Article
• Language: English
• Subjects: Astrophysics; Gamma rays; Stars & galaxies; X-rays
• ISSN: 1063-7737; 1562-6873
• DOI: 10.1134/1.1331158

The Spin-X wide-field X-ray monitor of the Spectrum-X-Gamma astrophysical observatory, which is based on the principle of a coded-aperture telescope, is designed to detect and localize cosmic gammaray-burst (GRB) sources; to survey large areas of the sky in search of new transients; and to carry out long-term observations of bright Galactic sources, including X-ray bursters. The monitor consists of two noncoaxial identical modules, Spin-X1 and Spin-X2, which together cover 6.8% of the sky. The high-apogee, four-day orbit of the Spectrum-XG satellite allows the instrument to be in observing mode more than 50% of the time. Having simulated the rate of GRB detection by Spin-X, we show that extrapolating BATSE 50-300-keV average data on the number of GRBs, their duration, and their mean energy spectrum to the X-ray energy band leads to disagreement with the observed detection rate of GRBs in the X-ray band. The number of GRBs that can be detected and localized with an accuracy r≤3' (3σ) (the error-circle radius) by Spin-X is estimated to be ten bursts per year. We present data on the Spin-X sensitivity achievable during long-term observations of persistent and transient sources and on its sensitivity to X-ray bursts from Galactic sources in the 2-30-keV energy band.[PUBLICATION ABSTRACT]