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20th of August 2021
WALLABY observations of the Eridanus supergroup
by B-Q For et al.
For et al. present observations of the Eridanus supergroup obtained with the Australian Square Kilometre Array Pathfinder (ASKAP) as part of the pre-pilot survey for the Widefield ASKAP L-band Legacy All-sky Blind Survey (WALLABY). The paper concludes by considering the place of the Eridanus supercluster within the cosmic Web. The cosmic web is a network of filaments with clustered galaxies and gases stretched across the Universe and separated by voids. It is seen in simulations and maps derived from galaxy redshift surveys. The so called the cosmic flow models are represented by the observed distribution of galaxies, peculiar velocities, and the underlying density field. The image above shows a 3-dimensional slice of the Universe centred at supergalactic position SGX=0 and the environment that the Eridanus supergroup resides in. The positions of the Eridanus supergroup galaxies are plotted against a map of the density contrast reconstructed from the Cosmicflows-3 Catalog of peculiar velocities. The map is obtained with the ray-casting volume rendering technique, resulting in a smooth representation of the dennsity contrast field ranging from most underdense (deep blue color) to most overdense (yellow), combined with a series of semi-transparent iso-surface polygons resulting in a sharp materialization of the surfaces ranging. The grey surface delineates the frontier between underdense and overdense patches of the local Universe. The model suggests that Eridanus supergroup is currently merging/falling onto the Fornax knot. An interactive 3-dimensional model is also available.

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