The Abell 3391/95 galaxy cluster system

Context. Inferences about dark matter, energy, and the missing baryons all depend on accuracy of our model large-scale structure evolution. In particular, with cosmological simulations in Universe, we trace growth structure, visualize build-up bigger structures from smaller ones gaseous filaments connecting galaxy clusters. Aims. Here aim to reveal complexity assembly process great detail scales tens kiloparsecs up more than 10 Mpc new sensitive observations latest generation instruments. We also compare findings expectations model. Methods. used dedicated SRG/eROSITA performance verification (PV) X-ray, ASKAP/EMU Early Science radio, DECam optical a ~15 deg 2 region around nearby interacting cluster system A3391/95 study warm-hot gas outskirts filaments, surrounding its formation process, morphological inner parts clusters, (re-)acceleration plasma. complementary Sunyaev-Zeldovich (SZ) effect data Planck survey custom-made Galactic total (neutral plus molecular) hydrogen column density maps based HI4PI IRAS surveys. relate hydrodynamic Magneticum suite. Results. irregular morphology warm hot main clusters their centers out well beyond characteristic radii, r 200 . Between two systems, observe an emission bridge large scale good spatial resolution. This includes known group but this can only partially explain emission. Most appears hot, thanks eROSITA’s unique soft response field view, discover some tantalizing hints for warm, truly primordial filamentary Several matter clumps physically are detected. For “Northern Clump,” provide evidence that it is falling towards A3391 X-ray radio lobe central AGN. Moreover, shapes these appear be formed by virial radius, 100 , A3391, thereby providing indirect way probing elusive environment. Many extended sources detected eROSITA or background, including SZ at redshift z = 1. find roughly order magnitude candidates SPT ACT surveys together same area. filament north radius Northern Clump. Furthermore, absorption-corrected surface brightness map shows extends south A3395 X-ray-emitting object (the “Little Southern Clump”) another cluster, redshift. The projected length continuous 15 Mpc, running almost 4 degrees across entire PV observation field. Filament each >4 σ additionally support presence both filaments. overdensities regions. Overall, datasets impressive confirmation theoretically expected processes individual level, intergalactic medium distribution; similarities features found similar simulation striking. Our spatially resolved show indeed reside clumpy structure.