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The XMM Large Scale Structure survey: The X-ray pipeline and survey selection function

F. Pacaud·M. Pierre·A. Refregier·A. Gueguen·J. -L. Starck·I. Valtchanov·A. M. Read·B. Altieri·L. Chiappetti·P. Gandhi·O. Garcet·E. Gosset·T. J. Ponman·J. Surdej
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Abstract

We present the X-ray pipeline developed for the purpose of the cluster search in the XMM-LSS survey. It is based on a two-stage procedure via a dedicated handling of the Poisson nature of the signal: (1) source detection on multi-resolution wavelet filtered images; (2) source analysis by means of a maximum likelihood fit to the photon images. The source detection efficiency and characterisation are studied through extensive Monte-Carlo simulations. This led us to define two samples of extended sources: the C1 class that is uncontaminated, and the less restrictive C2 class that allows for 50% contamination. The resulting predicted selection function is presented and the comparison to the current XMM-LSS confirmed cluster sample shows very good agreement. We arrive at average predicted source densities of about 7 C1 and 12 C2 per deg2, which is higher than any available wide field X-ray survey. We finally notice a substantial deviation of the predicted redshift distribution for our samples from the one obtained using the usual assumption of a flux limited sample.

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F. Pacaud, M. Pierre, A. Refregier, A. Gueguen, J. -L. Starck, I. Valtchanov, A. M. Read, B. Altieri, L. Chiappetti, P. Gandhi, O. Garcet, E. Gosset, T. J. Ponman, J. Surdej. 2006-07-10. The XMM Large Scale Structure survey: The X-ray pipeline and survey selection function. https://doi.org/10.1111/j.1365-2966.2006.10881.x

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