X-ray Surveys: The XMMLSS survey for high redshift groups, clusters & AGN

By studying a large, continuous area of sky at faint X-ray fluxes we are able to easily locate distant clusters and groups of galaxies and active galactic nuclei up to high redshifts, and study their evolution with redshift and distribution in 3D. We are part of the XMMLSS consortium constructing this large, multiwavelength survey using data from radio wavelengths, through the near and far infrared, optical and ultraviolet to X-rays. In particular we will study the evolution of the hot gas and galaxies within groups of galaxies, very high redshift clusters, and fossil groups.

Researchers: Trevor Ponman, Abdulmonem Alshino, Somak Raychaudhury, Graham Smith


This X-ray image of the extragalactic sky covers one of the largest areas of sky at faint X-ray fluxes ever obtained. It contains approximately 600 X-ray sources in an area of 2 sq deg (equivalent to 10 times the full moon). This survey is being used to locate and map out the distribution of distant clusters and groups of galaxies, and QSOs. An example of an extended cluster of galaxies can be seen above and slightly left of the image centre. The two white circles denote the only sources detected in this area in the ROSAT All-Sky survey at bright fluxes (one was probably a false detection).