Simulations of extragalactic magnetic fields and of their observables

Vazza, Franco; Brüggen, M.; Gheller, C.; Hackstein, Stefan; Wittor, Denis; Hinz, Philip M.

doi:10.1088/1361-6382/aa8e60

Cited by 136 publications

(249 citation statements)

References 180 publications

(312 reference statements)

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“…Magnetic fields in structures such as galaxies, clusters and perhaps filaments were amplified from their origins at nG levels (estimated for the IGM from models, Dolag et al 1999;Ryu et al 2008;Vazza et al 2014aVazza et al , 2017 to the µG levels we observe today.While largescale fields have been detected in galaxies and clusters, signatures of the fields' origins have been erased due to strong modification (Vazza et al 2015). Knowledge of the overall distribution of magnetic fields in the IGM, and their dependence on redshift, is a prerequisite to uncovering the history of magnetic field evolution.…”

Section: Introductionmentioning

confidence: 83%

Differences in Faraday Rotation between Adjacent Extragalactic Radio Sources as a Probe of Cosmic Magnetic Fields

Vernstrom

Gaensler

Rudnick

et al. 2019

ApJ

112

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Faraday rotation measures (RMs) of extragalactic radio sources provide information on line-of-sight magnetic fields, including contributions from our Galaxy, source environments, and the intergalactic medium (IGM). Looking at differences in RMs, ∆RM, between adjacent sources on the sky can help isolate these different components. In this work, we classify adjacent polarized sources in the NVSS as random or physical pairs. We recompute and correct the uncertainties in the NVSS RM catalog, since these were significantly overestimated. Our sample contains 317 physical and 5111 random pairs, all with Galactic latitudes |b| ≥ 20 • , polarization fractions ≥ 2%, and angular separations between 1.5 and 20 . We find an rms ∆RM of 14.9 ± 0.4 rad m −2 and 4.6 ± 1.1 rad m −2 for random and physical pairs, respectively. This means polarized extragalactic sources that are close on the sky, but at different redshifts, have larger differences in RM than two components of one source. This difference of ∼ 10 rad m −2 is significant at 5σ, and persists in different data subsamples. While there have been other statistical studies of ∆RM between adjacent polarized sources, this is the first unambiguous demonstration that some of this RM difference must be extragalactic, thereby providing a firm upper limit on the RM contribution of the IGM. If the ∆RMs originate local to the sources, then the local magnetic field difference between random sources is a factor of two larger than between components of one source. Alternatively, attributing the difference in ∆RMs to the intervening IGM yields an upper limit on the IGM magnetic field strength of 40 nG.

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Section: Introductionmentioning

confidence: 83%

Differences in Faraday Rotation between Adjacent Extragalactic Radio Sources as a Probe of Cosmic Magnetic Fields

Vernstrom

Gaensler

Rudnick

et al. 2019

ApJ

112

View full text Add to dashboard Cite

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“…2 (cf. Vazza et al 2017). The difference in |B|(ρ) between the two models is most prominent at very low density, far away from the central cluster regions, where most active galactic nuclei reside.…”

Section: Modelmentioning

confidence: 91%

“…Measuring their strength would allow to put reasonable constraints on the origin of those fields (e.g. Vazza et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Fast radio burst dispersion measures and rotation measures and the origin of intergalactic magnetic fields

Hackstein

Brüggen

Vazza

et al. 2019

Monthly Notices of the Royal Astronomical Society

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We investigate the possibility of measuring intergalactic magnetic fields using the dispersion measures and rotation measures of fast radio bursts. With Bayesian methods, we produce probability density functions for values of these measures. We distinguish between contributions from the intergalactic medium, the host galaxy and the local environment of the progenitor. To this end, we use constrained, magnetohydrodynamic simulations of the local Universe to compute lines-of-sight integrals from the position of the Milky Way. In particular, we differentiate between predominantly astrophysical and primordial origins of magnetic fields in the intergalactic medium. We test different possible types of host galaxies and probe different distribution functions of fast radio burst progenitor locations inside the host galaxy. Under the assumption that fast radio bursts are produced by magnetars, we use analytic predictions to account for the contribution of the local environment. We find that less than 100 fast radio bursts from magnetars in stellar-wind environments hosted by starburst dwarf galaxies at redshift z 0.5 suffice to discriminate between predominantly primordial and astrophysical origins of intergalactic magnetic fields. However, this requires the contribution of the Milky Way to be removed with a precision of ≈ 1 rad m −2 . We show the potential existence of a subset of fast radio bursts whose rotation measure carry information on the strength of the intergalactic magnetic field and its origins.

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“…Some recent works have also proved that the initial topology of the magnetic field has no relevant effects on the formation of cosmic structures such as galaxies and galaxy clusters (e.g. Marinacci et al 2015;Vazza et al 2017Vazza et al , 2018Domínguez-Fernández et al 2019).…”

Section: A Cosmological Application: Magnetic Fields In Galaxy Clustersmentioning

confidence: 99%

Cosmic magnetic fields with masclet: an application to galaxy clusters

Quilis

Martí

Planelles

2020

Monthly Notices of the Royal Astronomical Society

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We describe and test a new version of the adaptive mesh refinement (AMR) cosmological code MASCLET. The new version of the code includes all the ingredients of its previous version plus a description of the evolution of the magnetic field under the approximation of the ideal magneto-hydrodynamics (MHD). To preserve the divergence-free condition of MHD, the original divergence cleaning algorithm of Dedner et al. (2002) is implemented. We present a set of well-known 1D and 2D tests, such as several shock-tube problems, the fast rotor and the Orszag-Tang vortex. The performance of the code in all the tests is excellent with estimated median relative errors of ∇ · B in the 2D tests smaller than 5 × 10 −5 for the fast rotor test, and 5 × 10 −3 for the Orszag-Tang vortex. As an astrophysical application of the code, we present a simulation of a cosmological box of 40 comoving Mpc side length in which a primordial uniform comoving magnetic field of strength 0.1 nG is seeded. The simulation shows how the magnetic field is channelled along the filaments of gas and is concentrated and amplified within galaxy clusters. Comparison with the values expected from pure compression reveals an additional amplification of the magnetic field caused by turbulence in the central region of the cluster. Values of the order of ∼ 1µG are obtained in clusters at z ∼ 0 with median relative errors of ∇ · B below 0.4%. The implications of a proper description of the dynamics of the magnetic field and their possible observational counterparts in future facilities are discussed.

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Simulations of extragalactic magnetic fields and of their observables

Cited by 136 publications

References 180 publications

Differences in Faraday Rotation between Adjacent Extragalactic Radio Sources as a Probe of Cosmic Magnetic Fields

Differences in Faraday Rotation between Adjacent Extragalactic Radio Sources as a Probe of Cosmic Magnetic Fields

Fast radio burst dispersion measures and rotation measures and the origin of intergalactic magnetic fields

Cosmic magnetic fields with masclet: an application to galaxy clusters

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