Three of the ARCHES WPs aim at developing high quality, well-documented and scientifically validated multi-wavelength products. Associated software tools created in the framework of ARCHES will be extensively documented and personal trained for their use to ensure the usability of the ARCHES work beyond the end of the project.

WP4 - Cross-correlation tool development & catalogue creation

WP5 -SED tool development & SED creation

WP6 – Integrated cluster finder development and catalogue creation

• Cross-correlation tool development & catalogue creation (WP4)

WP4 aims at producing a complete set of XMM- Newton sources cross-identified with entries in the list of archival catalogues carefully selected in WP7. These archival catalogues will provide the best multi-wavelength flux information so as to derive a very reliable spectral energy distribution.

Planned activity :

The selected catalogues to be cross-identified with the XMM-Newton X-ray sources should encompass the largest possible wavelength range and provide the best calibrated flux information. Several cross-correlation techniques have been developed in the last years that carry out a careful statistical treatment of the cross-matching of two catalogues. In order to fulfil ARCHES’s goals, we need to extend the capabilities of our cross matching tools in order to properly handle complex priors on SEDs when needed while taking into account an arbitrary large number of catalogues.

The design, testing and validation of the cross- matching tools is extremely important in order to guarantee the reliability of the cross-identifications and to provide for each of them a true probability of occurrence.

Several cross-correlation runs will be required in order to test the scientific quality of the output and collect feedback. (WP8)

Under the responsibility of the University of Strasbourg solely, the outcome of this WP includes:

-A software tool allowing the statistical cross-identification of several archival astronomical catalogues. The tool was created and delivered including proper documentation.

-A reference catalogue which contains for each entry of the enhanced 3 XMM catalogue (outcome of WP3) the best multi-wavelength source identifications extracted from the selected archival catalogues (outcome of WP7)

• SED tool development & SED creation (WP5)

WP5 aims at producing a scientifically validated, VO-compliant set of spectral energy distributions of the objects included in the 3XMM- Newton Catalogue.

Planned activity:

The leader of this WP is the Virtual Observatory group at the Instituto Nacional de Técnica Aeroespacial, which is also responsible for the development of the VOSED SED creation tool. University of Cantabria, which has a strong experience in scientific research based on the XMM catalogue will also contribute to this WP tasks. These include: writing specifications to improve the VOSED tool, designing, developing, implementing as well as testing, optimizing and validating the new functionalities and finally building the spectral energy distributions of the objects extracted from the 3XMM enhanced catalogue.

The outcome for this WP is:

-The creation of an SED building tool with an access system and taking into account feedback from WP8 and including documentation.

-A scientifically validated spectral energy distributions of the objects included in the enhanced 3 XMM Catalogue (WP3) together with appropriate documentation.

• Integrated cluster finder development and catalogue creation (WP6)

WP6 aims at developing a software tool that searches for galaxy clusters simultaneously in X-ray images obtained with XMM-Newton and in ground- and space-based multi-wavelength imaging. The cosmological redshift will be measured using the spectral energy distribution (SED, WP4) of the member galaxies and of the central dominant galaxy, supplemented by optical spectra if available (WP6). The validated catalogue will be disseminated into the community for fast access and scientific exploitation.

Planned activity:

The integrated cluster finder seeks to enhance the XMM-Newton catalogue by applying a combined multi-wavelength search strategy to confirm an extended X-ray source as originating from a galaxy cluster in the first place and to determine the properties of the cluster in the second place. In the past cluster X-ray searches were performed sequentially, the sky region around an extended X-ray source was searched manually for galaxy over-densities with similar colour to confirm the tentative identification. It is proposed here to develop a novel integrated approach for unsupervised cluster search and parameter identification. A joint probabilistic assertion shall be derived that combines X-ray source extent with clustering of galaxies that have similar colour indicating the same redshift.

The reliability of the method will depend on the depths and comprehension (wavelength coverage) of the available optical/near infrared imaging data, the sensitivity of the X-ray observations, the redshift and the extent of the galaxy cluster and will be described explicitly. The redshift and hence the luminosity of the clusters will be determined based on multi-colour imaging and in few cases from the X-ray spectra. The joint cluster probability, the derived redshift, the optical richness and the X-ray luminosity will be published in the cluster catalogue. The software tool will be equipped with sufficient flexibility to incorporate new imaging data archives when they come online.

Under the sole responsibility of the Astrophysik Institut Potsdam, this WP has delivered two products:

- A validated software tool “Integrated Cluster Finder” ready for comprehensive use to generate cluster catalogue. This includes a user’s guide and documentation.

-A cluster catalogue constructed with the ICF, including proper documentation