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| Paper: |
X-ray Astronomy and the Analysis of X-ray Data |
| Volume: |
351, Astronomical Data Analysis Software and Systems XV |
| Page: |
47 |
| Authors: |
McDowell, J.C. |
| Abstract: |
The Chandra X-ray Observatory, launched in 1999, continues to return spectacular scientific results thanks to its combination of high spatial and spectral resolution. I will discuss a selection of these results, and draw attention to the specific data analysis challenges posed by X-ray observatories in general, leading to the identification of the spatial distribution of elements in supernova remnants, the discovery of X-ray jets in galactic and extragalactic objects, the resolution of the X-ray background into faint sources, and the analysis of X-ray spectra of individual sources in external galaxies. The X-ray event list paradigm provides a compact representation of a sparse multidimensional dataset, supporting time- and energy-resolved hundred-megapixel images. In contrast to the case of HST and ground-based telescopes, the pointing of X-ray telescopes, while known accurately after the fact, is not kept constant during the observation. Sharp X-ray images are reconstructed from a dithered picture using star tracker data. The imaging point spread function and spectral energy response vary greatly across the field of view and must be carefully calibrated. For X-ray CCD data, the line spread function is broad and multi-peaked, driving us to forward-fitting solutions. For high resolution grating data, order separation is a challenge. Finally, in all X-ray data the low count rate and the ubiquitous cosmic X-ray background require careful statistical attention. Despite these complexities, the standard data analysis packages like CIAO, HEASOFT and SAS are mature enough to allow non-specialist users to reliably extract high quality science from X-ray observations. |
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