On the largest scales, galaxies are pulled together by gravity to form clusters, which are connected by filaments making a web-like pattern. Radio emission is predicted from this cosmic web, which should originate from the strong accretion shocks around the cosmic structures. We present the first observational evidence that Fermi-type acceleration from strong shocks surrounding the filaments of the cosmic web, as well as in peripherals of low-mass clusters, is at work in the Universe. Using all-sky radio maps and stacking on clusters and filaments, we have detected the polarization signature of the synchrotron emission with polarization fractions ≥20%, which is best explained by the organization of local magnetic fields by strong shock waves both at the cluster peripheries and between clusters. Our interpretation is well supported by a detailed comparison with state-of-the-art cosmological simulations.

Vernstrom T., West J., Vazza F., Wittor D., Riseley C.J., Heald G. (2023). Polarized accretion shocks from the cosmic web. SCIENCE ADVANCES, 9(7), 1-15 [10.1126/sciadv.ade7233].

Polarized accretion shocks from the cosmic web

Vazza F.;Wittor D.;
2023

Abstract

On the largest scales, galaxies are pulled together by gravity to form clusters, which are connected by filaments making a web-like pattern. Radio emission is predicted from this cosmic web, which should originate from the strong accretion shocks around the cosmic structures. We present the first observational evidence that Fermi-type acceleration from strong shocks surrounding the filaments of the cosmic web, as well as in peripherals of low-mass clusters, is at work in the Universe. Using all-sky radio maps and stacking on clusters and filaments, we have detected the polarization signature of the synchrotron emission with polarization fractions ≥20%, which is best explained by the organization of local magnetic fields by strong shock waves both at the cluster peripheries and between clusters. Our interpretation is well supported by a detailed comparison with state-of-the-art cosmological simulations.
2023
Vernstrom T., West J., Vazza F., Wittor D., Riseley C.J., Heald G. (2023). Polarized accretion shocks from the cosmic web. SCIENCE ADVANCES, 9(7), 1-15 [10.1126/sciadv.ade7233].
Vernstrom T.; West J.; Vazza F.; Wittor D.; Riseley C.J.; Heald G.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/956386
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