The X-ray planetary nebulae database

Planetary nebulae (PNe) are one of the latest additions to the zoo of X-ray sources. XMM-Newton and Chandra observations have finally detected diffuse X-ray emission from shocked fast winds in PN interiors and from bow-shocks of fast collimated outflows impinging on nebular envelopes. These X-ray observations have produced exquisite images and invaluable spectra of PNe that allow us to examine the spatial distribution and physical properties of hot gas in PN interiors. However, X-ray observations of PNe have not been optimally used, as papers reporting X-ray analysis of PN emission applied preliminary calibrations and methods which have since been significantly improved, and X-ray observations of PNe resulting in non-detections are often left in the archive without appearing in the literature. To present a homogeneous analysis of recent X-ray observations of PNe, we introduce the XPN Database webpage, http://www.iaa.csic.es/xpn, which highlights all XMM-Newton and Chandra observations of PNe that are available in the archives. We have processed these observations using the most up-to-date calibration files and we make the data at different processing levels available to the astronomical community through this webpage. These X-ray observations have been analyzed consistently using the most recent versions of SAS and CIAO. Statistical analyses of the X-ray and physical properties of PNe can yield crucial constraints on the formation and evolution of PNe.