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Filaments of the radio cosmic web: opportunities and challenges for SKA
Conference proceeding   Open access

Filaments of the radio cosmic web: opportunities and challenges for SKA

Franco Vazza, Chiara Ferrari, Annalisa Bonafede, Marcus Brüggen, Claudio Gheller, Robert Braun and Shea Brown
Advancing Astrophysics with the Square Kilometre Array (AASKA14) - Session 6: Magnetism
Proceedings of Science, v. 215
05/29/2015
DOI: 10.22323/1.215.0097
url
https://doi.org/10.22323/1.215.0097View
Published (Version of record) Open Access

Abstract

The detection of the diffuse gas component of the cosmic web remains a formidable challenge. In this work we study synchrotron emission from the cosmic web with simulated SKA1 observations, which can represent an fundamental probe of the warm-hot intergalactic medium. We investigate radio emission originated by relativistic electrons accelerated by shocks surrounding cosmic filaments, assuming diffusive shock acceleration and as a function of the (unknown) large-scale magnetic fields. The detection of the brightest parts of large (\(>10 \rm Mpc\)) filaments of the cosmic web should be within reach of the SKA1-LOW, if the magnetic field is at the level of a \(\sim 10\) percent equipartition with the thermal gas, corresponding to \(\sim 0.1 \mu G\) for the most massive filaments in simulations. In the course of a 2-years survey with SKA1-LOW, this will enable a first detection of the "tip of the iceberg" of the radio cosmic web, and allow for the use of the SKA as a powerful tool to study the origin of cosmic magnetism in large-scale structures. On the other hand, the SKA1-MID and SKA1-SUR seem less suited for this science case at low redshift (\(z \leq 0.4\)), owing to the missing short baselines and the consequent lack of signal from the large-scale brightness fluctuations associated with the filaments. In this case only very long exposures (\(\sim 1000\) hr) may enable the detection of \(\sim 1-2\) filament for field of view in the SKA1-SUR PAF Band1.
 Acceleration Emission analysis Field of view Filaments Intergalactic media Magnetic fields Magnetism Radio emission Red shift Variations Webs

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