All Magnetic Projects

Challenging simulations
We produced some of the ​​​ largest cosmological simulations of extragalactic magnetic fields to-date, using the ENZO code, to study how magnetic fields in large-scale structures may have originated. 

Data repository (via B2Share)
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What is the origin of extragalactic magnetic fields?

The observed ~μG  magnetic field in galaxy clusters may  be equally explained by a “primordial" scenario (i.e.  small-scale dynamo amplification of primordial weak fields) or by an “astrophysical” scenario (i.e. fields were injected by  winds/jets from AGN at lower redshift). 
With our MHD  cosmological simulations we can allow future radio surveys   to probe cluster outskirts and cosmic filaments, where old traces of magnetogenesis should still still be present. 

"primordial scenario"

"astrophysical scenario"

Related works​   
Public repository of data

main contributors: ​ F. Vazza C. Gheller M. Brüggen, W. Wittor

Can we detect the magnetic cosmic web?

The incoming generation of radio telescopes (e.g. LOFAR , MWA , ASKAP , MEERKAT ...and   SKA  on top of them all) should be able to detect the iceberg of the cosmic web. Through the assistance of big simulations (combining the complexity of physics and of radio observing procedures) we want to enable radio observations to maximise their chance of discovery.  Producing mock radio observations of our simulated volumes and connecting complex signals to the underlying gas physics is crucial here.
Related works​   
Public repository of data
SIRIO radio simulator

main contributors: ​ F. Vazza , N. Locatelli,  C. Ferrari  , C. Gheller M. Brüggen A. Bonafede

Magnetic fields in galaxy clusters & particle acceleration

Understanding how cluster dynamics forces magnetic fields to evolve allows us to better understand non-thermal emission from galaxy clusters.
The link between cluster dynamics and the emergence of ~Mpc wide magnetic fields is not yet fully understood, and high-resolution MHD simulations may come to the rescue. 
The small-scale properties of the cluster magnetic field may also affect the efficiency at which cosmic rays get (or not) accelerated by shocks.
Related works​   

main contributors: F. Vazza , M. Brüggen , D. Wittor , A. Bonafede , D. Eckert , C.Ferrari, K. Basu

Propagation of Ultra-high energy cosmic rays

What is the the origin of ultra-high energy cosmic rays?
These particles should originate from outside the Milky Way, and their direction of propagation can be deflected by magnetic fields  outside our galaxy. Only if the magnetic fields outside the Milky Way are below a certain level, the trajectories of ultra-high energy cosmic rays remain rectilinear enough to point towards their exact sources.  But predicting the exact strength and topology of these magnetic fields is non trivial, as it requires advanced numerical simulations. 
We are combining ENZO-MHD simulations to in order to the CRPropa code  to predict the deflection of UHECRs by possible extragalactic magnetic fields, also employing constrained simulations of the Local Universe. 
Related works​   
  • "Propagation of Ultra High Energy Cosmic Rays in Extragalactic Magnetic Fields: A view from cosmological simulations ​" ( Hackstein et al. 2016 MNRAS )
  • Bachelor Thesis by Stefan Hackstein at Hamburg University (2015)
  • "Simulations of UHECRs in the Local Universe and the Origin of Extragalactic Magnetic Fields" ( Hackstein et al. 2017 MNRAS )

main contributors: S. Hackstein,  F. Vazza , M. Brüggen , G. Sigl , A. Dundovic, S. Gottlober, J. Sorce

The oscillation of Axionlike particles

An important candidate for dark matter is represented by "​​ Axion-like particles " (ALPs). On of their most interesting properties is that they couple with the magnetic fields, and can oscillate into high-energy photons (and back). This would explain the lack of IR absorption of the spectra of TeV sources at high redshift.
With our simulations we can explore the space of parameters allowed by current model of ALPs, and see if the observed spectra can be explained by ALPs oscillations in presence of realistic magnetic fields on cosmic scales.
Public repository of data

Related works​   
  • "Enhancing the spectral hardening of cosmic TeV photons by the mixing with axion-like particles in the magnetised cosmic web" , Montanino,Vazza,Mirizzi & Viel, 2017 PRL
  • PRESS RELEASE by INAF , SISSA & Research Italy

main contributors: ​​​​ D. Montanino ,   F. Vazza , M. Viel A. Mirizzi