Jet-X at MSSL |
Jet-X - Scientific objectives |
The scientific potential of JETX derives from its high spatial and good energy resolution, the advantageous orbit of Spectrum-X-Gamma and its timeliness in relation to later, larger X-ray missions, such as AXAF and XMM.
The low intrinsic noise of the system allows long, photon limited exposures, yielding a sensitivity limit near 3 x 10-15 erg/cm2/s, ten times fainter than the Einstein deep Survey limit, and similar to the ROSAT Deep Survey limit. This sensitivity will remain un-confused (at 40 beams per source) provided JETX achieves an angular resolution of better than 30 arcsec HEW. Also the higher energy response makes JETX a valuable extension to ROSAT, for example in determining temperature structures in clusters of galaxies and detecting the important Fe K-features in active galaxies.
The major scientific goal of JETX is a study of faint X-ray sources, by spectroscopy, imaging and timing. The high resolution optics, low noise detectors and 4-day orbit, combine to emphasise the value of long exposures for JETX.
The key scientific objectives of JETX are:
Direct measurement of source counts, to a level corresponding to approx. 0.5 of the X-ray background flux, hence identifying the major constituent(s) of the XRB in the 2-10 keV band (and possibly revealing an entirely new class of faint, strongly evolving sources). See here for an expanded explanation of deep fields.
Broad-band spectroscopy of many X-ray sources detected in the ROSAT survey, yielding information on the possible evolution of the X-ray emission and absorption in AGN, etc.
Imaging and spectroscopy of rich clusters, elliptical galaxies, SNRs, etc. to determine their temperature, density and chemical abundance distributions; hence their mass and evolution.
Time variation and spectroscopy of interacting binary systems, stars etc.
Astrophysics
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