It is known that there is a disagreement between the observed and predicted number of baryons in the Universe. The theory suggests that these missing baryons may be located in the cosmic web filaments, namely, the Warm-Hot Intergalactic Medium (WHIM). The most commonly used objects to probe WHIM are galaxy clusters, since these extremely massive collapsed objects are located in the intersections of the filaments. The most advantageous geometry to detect WHIM is predicted to be the region between two nearby galaxy clusters. One such system is the interacting galaxy cluster system Abell 3391 and Abell 3395 (A3391/95).
The A3391/95 system has previously been observed by several X-ray telescopes, e.g. ROSAT, Chandra, Suzaku, XMM-Newton. Soft emission originating from the region between these two clusters was detected, however, only faintly. This emission was also seen with Planck in the (sub)mm regime. The newly launched X-ray telescope, eROSITA shows over a large area and in great detail the presence of a filament-like structure that bridges these clusters. Further investigation still needs to be done to determine the properties of this structure and the system itself. With this goal in mind, I will present a spectral analysis of the A3391/95 system with XMM-Newton, which will later be cross-calibrated with eROSITA.
|Presenter status||eROSITA consortium member|