Why IXO?

An X-ray view of the Universe on very large scales: XMM-Newton EPIC image of the Coma Cluster of galaxies (this image is several degrees across).

High-energy phenomena – particularly in the X-ray band – characterize the evolution of cosmic structures on both large and small scales. On the smallest scales, X-rays provide the only electromagnetic spectral signatures from the regions of strong gravity near black holes and neutron stars. X-rays from these energetic processes penetrate absorbing gas allowing us to uncover the earliest massive black holes. On the largest scales, X-rays are indispensible for detecting the “missing” 50% of baryons in the local Universe, and as a probe of both dark energy and dark matter.

IXO will have the necessary instrumental improvements beyond the current generation of X-ray missions (e.g. Chandra, XMM, RXTE, and Suzaku) in X-ray imaging, timing, and spectroscopy to enable these advances.

IXO will have:

the spectral sensitivity and resolution to obtain high quality data for large numbers of almost every class of object from planets to quasars
a sensitive and wide field imaging capability with sufficient angular resolution to find and study very large numbers of all classes of objects
the timing resolution to measure the fundamental parameters of the effects of strong gravity

In addition, IXO will be complementary to the next generation of observatories including ALMA, LSST, JWST, and 30-m ground based telescopes. This is absolutely critical as modern astrophysics requires a panchromatic outlook. Many of the data sets obtained by these new observatories will require IXO data to produce the highest quality science.