The Magnetised Cosmic Web

Project Information

MAGCOW

Grant agreement ID: 714196

DOI

10.3030/714196

Project closed

EC signature date 15 December 2016

Start date 1 September 2017

End date 31 March 2023

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 465 943,00

EU contribution

€ 1 465 943,00

Coordinated by

ALMA MATER STUDIORUM - UNIVERSITA DI BOLOGNA
Italy

Periodic Reporting for period 4 - MAGCOW (The Magnetised Cosmic Web)

Reporting period: 2022-03-01 to 2023-03-31

Summary of the context and overall objectives of the project

This project investigates the origin of observed extragalactic magnetic fields in the Universe, combining advanced numerical simulations and existing or new radio observations.
All publications produced in the course of the project are closely related to the above topic, in the attempt of obtaining the widest and most complete ever of the origin
and effects of cosmic magnetism at cosmological scales.

To this end, in our projects we investigated, both, purely theoretical models of the cosmic web, real observations, or combined the two methods.

All publications of the project were made timely available via the arXiv repository (www.arxiv.org) always soon after official acceptance by the editors, and often even before this, as preprints.
Moreover, the open access to all publications produced by the project is also timely enabled by its submission to the https://cris.unibo.it open access official repository of the University of Bologna.

We produced more than a hundred peer-review publications during the granting period (the exact number is not settled as several papers are in the course of acceptance and proof-reading with different journals as in the moment of writing).

Several of our works ended up being published in the highest ranking scientific journals: Science (1), Nature (1), Nature Astronomy (2), Science Advances (2) and Physical Review Letters (2).

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Continuous activity of production and analysis of new, challenging magneto-hydrodynamical simulations of cosmic structures.
Modelling of existing radio data, guided by theoretical analysis.
Continuous activity of proposing new radio observation (to be gained through international and competitive call for applications of observing time) to fill existing gaps in our understanding of cosmic magnetism and evolution.
Innovative analysis and modelling techniques to extract information on cosmic magnetism from radio observations, and connect them with the physical expectations and scenarios of our numerical simulations.
Simulations of small-scale interactions between cosmic rays and magnetic fields, using Particle-In-Cell simulations, and extrapolation of these data on larger scales.
Connection between cosmic magnetism and cosmology, through the usage of complex network analysis techniques.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

In MAGCOW we produced the most sophisticated numerical models of cosmic magnetism so far, and investigated their outcome and observational properties under several different scenarios for the origin of seed fields and for their amplifications.
This allowed us to connect observations and theory with unprecedented realism and depth of inference.
In detail, from the theoretical and numerical viewpoint, we

- produced the first successful simulation ever of the growth of small-scale dynamo in a simulated galaxy clusters with the ENZO-MHD code;
- produced the complete suite of cosmological MHD simulations to-date (more than 30 models) comparing the observable outcomes of magnetogenesis scenarios on different scales;
- produced the first simulations of primordial magnetogenesis scenarios, also connected with Local Universe resimulations and updated constraints from the CMB analysis;
- produced the first predictions for the synchrotron polarisation signatures from the shocked cosmic web, as well as for very long lightcones of Faraday Rotation measurements for different scenarios, up to redshift 3.
- produced the first sophisticated numerical investigations of new mechanism to (pre)accelerate radio emitting electrons in merging clusters of galaxies, to study new regimes of particle acceleration discovered within the activity or collaborations of MAGCOW.

From the observational view point, we
- participated to the first discovery of "Radio Bridges" between pre-merger clusters of galaxies;
- participated to the first discovery of "Mega Radio Halos", a new class of radio sources extending much beyond classical radio halos;
- participated to the fist detection of the shocked cosmic web via stacking, both in total intensity & polarisation;
- participated to the detection of the statistical signature of cosmic magnetism from filaments in faraday rotation observations;
- discovered a new, faint class of radio relics, likely to be entirely powered by weak shock direct acceleration:
- explored new, uncharted territory in the production of faint and filamentary radio emission within the substructures of giant radio relics.

The discovery of a giant magnetic intracluster bridge between A399 and A401 (from Govoni et al.2019)

High resolution cosmological simulations from Vazza et al. 2018 MNRAS