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A new supercluster seen by Planck and XMM-Newton
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A new supercluster, seen by Planck and XMM-Newton

January 25, 2013
This image shows the newly discovered supercluster of galaxies detected by Planck (with the Sunyaev-Zel'dovich Effect) and XMM-Newton (in X-ray emission). This is the first supercluster to be discovered through its Sunyaev-Zel'dovich Effect. Combined with other observations, the Sunyaev-Zel'dovich Effect allows astronomers to measure the physical properties of the hot gas (such as temperature and density) in which the galaxies are embedded. The bright orange blob in the left panel shows the Sunyaev-Zel'dovich image of the supercluster, obtained by Planck. After Planck's detection, follow-up observations were performed with the XMM-Newton observatory in the framework of a Planck source validation programme undertaken in Director's Discretionary Time. The right panel shows the X-ray image of the supercluster obtained with XMM-Newton, which reveals the three galaxy clusters that comprise this supercluster. The X-ray contours are also superimposed on the Planck image, as a visual aid. The Sunyaev-Zel'dovich signal from the newly discovered supercluster arises from the sum of the signal from the three individual clusters, with a possible additional contribution from an inter-cluster filamentary structure. The angular separation between the upper cluster and the one in the bottom-right is about 7.5 arc minutes. The small, round contours scattered throughout the field are not related to the supercluster; they are point-like X-ray sources located either in the background or foreground of the supercluster, and are most likely Active Galactic Nuclei. The X-ray emission shown in the XMM-Newton image corresponds to the energy range between 300 eV and 2000 eV, a temperature range of 3.5 million K to 23 million K, respectively. The size of the image is about 15 arc minutes. Copyright: Planck image: ESA/LFI & HFI Consortia; XMM-Newton image: ESA