Forecasts for the detection of the magnetised cosmic web from cosmological simulations^⋆

¹ Hamburger Sternwarte, Gojenbergsweg 112, 21029 Hamburg, Germany
e-mail: franco.vazza@hs.uni-hamburg.de
² INAF/Istituto di Radioastronomia, via Gobetti 101, 40129 Bologna, Italy
³ Laboratoire Lagrange, UMR 7293, Université Nice Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, 06300 Nice, France
⁴ CSCS, via Trevano 131, 6900 Lugano, Switzerland
⁵ NVIDIA, Santa Clara, CA 95050, USA

Received: 31 March 2015
Accepted: 20 June 2015

Abstract

The cosmic web contains a large part of the total gas mass in the Universe, but it is difficult to detect at most wavelengths. Synchrotron emission from shock-accelerated electrons may offer the chance of imaging the cosmic web at radio wavelengths. In this work we use 3D cosmological ENZO-magnetohydrodynamic simulations (combined with a post-processing renormalisation of the magnetic field to bracket for missing physical ingredients and resolution effects) to produce models of the radio emission from the cosmic web. In post-processing we study the capabilities of 13 large radio surveys to detect this emission. We find that surveys by LOFAR, SKA1-LOW, and MWA have a chance of detecting the cosmic web, provided that the magnetisation level of the tenuous medium in filaments is of the order of ~1% of the thermal gas energy.