XMM-Newton Pipeline Processing System

 

The aim of the XMM-Newton Pipeline Processing System (PPS) is to provide a set of data products which are of immediate value for the XMM-Newton observer as well as for the XMM-Newton Science Archive (XSA), where they are also stored for eventual public release. The pipeline products, together with the ODF, are distributed to observers by the XMM-Newton Science Operations Centre (SOC) via the XSA.

The dedicated pipeline reduces data from each of the EPIC, RGS and OM science instruments on XMM-Newton, using the same SAS software packages that are available for users to interactively analyse XMM-Newton data. The pipeline is composed of several modules which execute one or more SAS tasks.

The resulting pipeline products are a mixture of files that are useful as inputs to further scientific analysis by the user and files that provide a first cursory view of the data. The products include calibrated cleaned event lists for all X-ray cameras, sky images, source lists, cross-correlations with archival catalogues (performed by the Astronomical Catalogues Database Subsystem (ACDS) at the Observatoire Astronomique de Strasbourg), and spectra and time series of sufficiently bright individual sources. These provide a useful overview of the observation for the XMM-Newton observer as well as constituting key archival resources. The pipeline data products are described in detail in a document available on the SOC Manuals web page, under the Data Handling section.

Before the pipeline products are delivered, each dataset processed is subject to a screening process performed by members of the XMM-Newton Survey Science Centre (SSC) and SOC teams. This exercise aims at verifying the quality of the products and to identify any processing issues.

The timescale for the whole process, between the time the observations are performed and the delivery of the PPS products to the observer, is less than one month (typically less than 2 weeks).

The pipeline infrastructure used to carry out the processing was originally developed, maintained and run by SSC. On March 1st 2012, pipeline processing was transferred to the XMM-Newton SOC. Since July 2013 the XMM-Newton SOC retains full pipeline software development and maintenance responsibility as well. First pipeline with significant changes introduced at the SOC became operational on February 1st, 2015.