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)
Project Blog
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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
- "On the amplification of magnetic fields in cosmic filaments and galaxy clusters" ( Vazza et al. 2014 MNRAS )
- "Numerical cosmology on the GPU with Enzo and Ramses" ( Gheller et al. 2015 JPhCS )
- "Forecasts for the detection of the magnetised cosmic web from cosmological simulations" (
Vazza et al. 2015 A&A
)
- "Detecting the cosmic web with radio surveys" ( Vazza et al. 2015 PoS )
- "Evolution of cosmic filaments and of their galaxy population from MHD cosmological simulations" (
Gheller, Vazza et al. 2016 MNRAS
)
- "On the non-thermal energy content of cosmic structures" (
Vazza et al. 2016 Galaxies
)
- "The quest for extragalactic magnetic fields" ( Vazza 2016, PoS)
- "Evolution of vorticity and enstrophy in the intracluster medium" ( Wittor+2017, MNRAS )
- "Simulations of extragalactic magnetic fields and of their observables" ( Vazza+2017 CQG )
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
-
"Filaments of the radio cosmic web: opportunities and challenges for SKA" ( Vazza et al. 2015 PoS )
- "Forecasts for the detection of the magnetised cosmic web from cosmological simulations" (
Vazza et al. 2015 A&A
)
- "Unravelling the origin of large-scale magnetic fields in galaxy clusters" (
Bonafede et al. 2015 PoS
)
and beyond through Faraday Rotation Measures with the SKA - "Detecting the cosmic web with radio surveys" ( Vazza et al. 2015 PoS )
- "Simulations of extragalactic magnetic fields and of their observables"
(Vazza+2017 CQG)
Public repository of data
SIRIO radio simulator
main contributors:
F. Vazza
,
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
- "Electron and proton acceleration efficiency by merger shocks in galaxy clusters" (
Vazza et al. 2015 MNRAS
)
- "Unravelling the origin of large-scale magnetic fields in galaxy clusters" (
Bonafede et al. 2015 PoS
)
and beyond through Faraday Rotation Measures with the SKA - "Non-thermal emission from galaxy clusters: feasibility study with SKA" ( Ferrari et al. 2015 PoS )
- "Radio haloes in Sunyaev-Zel'dovich-selected clusters of galaxies: the making of a halo?" (
Bonafede et al. 2015 MNRAS
)
- "Constraining the efficiency of cosmic ray acceleration by cluster shocks (
Vazza et al. 2016 MNRAS
)
- "A shock front at the radio relic of Abell 2744" (
Eckert et al. 2016 MNRAS
)
- "The impact of the SZ effect on cm-wavelength (1-30 GHz) observations of galaxy cluster radio relics" (
Basu et al. 2016 MNRAS
)
- "Testing cosmic-ray acceleration with radio relics: a high-resolution study using MHD and tracers" (
Wittor, Vazza & Bruggen 2016 MNRAS
)
- "Sardinia Radio Telescope observations of Abell 194 - the intra-cluster magnetic field power spectrum" (
Govoni et al. 2017 A&A)
-
"Observations of the galaxy cluster CIZA J2242.8+5301 with the Sardinia Radio Telescope" (
Loi et al. 2017 A&A)
- "On the Connection between Turbulent Motions and Particle Acceleration in Galaxy Clusters"
(Eckert et al. 2017 ApJ)
- "Evolution of vorticity and enstrophy in the intracluster medium" (Wittor et al. 2017 MNRAS)
- "Resolved small-scale dynamo action in the simulated intracluster medium (Vazza et al. 2018 MNRAS)
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