Magnetic fields in barred galaxies

Beck, Rainer; Shoutenkov,; Ehle, M.; Harnett, J.; Haynes, R. F.; Shukurov, Anvar; Sokoloff, D.; Thierbach, Michael

doi:10.1051/0004-6361:20020642

Cited by 61 publications

(66 citation statements)

References 60 publications

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“…This form can be substantially distorted in the presence of strong noncircular motions, e.g. in barred galaxies, see Beck et al (1999Beck et al ( , 2002, Moss et al (2001).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear magnetic diffusion and magnetic helicity transport in galactic dynamos

Kleeorin¹,

Moss²,

Rogachevskii³

et al. 2003

A&A

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Abstract.We have extended our previous mean-field galactic dynamo model which included algebraic and dynamic alpha nonlinearities (Kleeorin et al. 2002), to include also a quenching of the turbulent diffusivity. We readily obtain equilibrium states for the large-scale magnetic field in the local disc dynamo model, and these fields have strengths that are comparable to the equipartition field strength. We find that the algebraic nonlinearity alone (i.e. quenching of both the α effect and turbulent magnetic diffusion) cannot saturate the growth of the mean magnetic field; only the combined effect of algebraic and dynamic nonlinearities can limit the growth of the mean magnetic field. However, in contrast to our earlier work without quenching of the turbulent diffusivity, we cannot now find satisfactory solutions in the no-z approximation to the axisymmetric galactic dynamo problem.

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“…This form can be substantially distorted in the presence of strong noncircular motions, e.g. in barred galaxies, see Beck et al (1999Beck et al ( , 2002, Moss et al (2001).…”

Section: Introductionmentioning

confidence: 99%

Nonlinear magnetic diffusion and magnetic helicity transport in galactic dynamos

Kleeorin¹,

Moss²,

Rogachevskii³

et al. 2003

A&A

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“…This means that magnetic fields are dynamically passive, which has been confirmed by polarization observations of bar galaxies (e.g. Beck et al 2002). Polarized emission has also been detected in the halos of some edge-on galaxies (e.g.…”

Section: Diffuse Radio Polarized Emissionmentioning

confidence: 59%

Magnetic fields in our Milky Way Galaxy and nearby galaxies

Han

2012

Proc. IAU

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Abstract. Magnetic fields in our Galaxy and nearby galaxies have been revealed by starlight polarization, polarized emission from dust grains and clouds at millimeter and submillimeter wavelength, the Zeeman effect of spectral lines or maser lines from clouds or clumps, diffuse radio synchrotron emission from relativistic electrons in interstellar magnetic fields, and the Faraday rotation of background radio sources as well as pulsars for our Milky Way. It is easy to get a global structure for magnetic fields in nearby galaxies, while we have observed many details of magnetic fields in our Milky Way, especially by using pulsar rotation measure data. In general, magnetic fields in spiral galaxies probably have a large-scale structure. The fields follow the spiral arms with or without the field direction reversals. In the halo of spiral galaxies magnetic fields exist and probably also have a large-scale structure as toroidal and poloidal fields, but seem to be slightly weaker than those in the disk. In the central region of some galaxies, poloidal fields have been detected as vertical components. Magnetic field directions in galaxies seem to have been preserved during cloud formation and star formation, from large-scale diffuse interstellar medium to molecular clouds and then to the cloud cores in star formation regions or clumps for the maser spots. Magnetic fields in galaxies are passive to dynamics.

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“…In several barred galaxies the topology of magnetic field is very similar to NGC 1365 (e.g. NGC 1672, NGC 7552 and NGC 1097 -Beck et al 2002). In spiral galaxies the synchrotron observations also reveal the presence of strong polarized halos extending few kiloparsecs from the disks and having the X-shape topology.…”

Section: Introductionmentioning

confidence: 75%

“…The sample of 20 radio emission maps of barred galaxies (Beck et al 2002) show that the central region of the galaxy NGC 1365 has the strongest polarized emission. In the outer disk of this galaxy the polarized magnetic arms are well visible between the bar and spiral arms similarly to spiral galaxies.…”

Section: Introductionmentioning

confidence: 99%

3D numerical simulations of magnetic field evolution in barred galaxies and in spiral galaxies under influence of tidal forces

Otmianowska-Mazur¹,

Kulpa-Dybeł²,

Kulesza-Żydzik³

et al. 2010

Proc. IAU

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Abstract. We present the results of the three-dimensional, fully non-linear MHD simulations of the large-scale magnetic field evolution in a barred galaxy with the back reaction of magnetic field to gas. We also include the process of the cosmic-ray driven dynamo. In addition, we check what physical processes are responsible for the magnetic field evolution in the tidally influenced spiral galaxies. We solve the MHD equations for the gas and magnetic field in a spiral galaxy with gravitationally prescribed bulge, disk and halo which travels along common orbit with the second body. In order to compare our modeling results with the observations we also construct the maps of high-frequency (Faraday rotation-free) polarized radio emission from the simulated magnetic fields. The model accounts for the effects of projection and limited resolution.We found that the obtained magnetic field configurations are highly similar to the observed maps of the polarized intensity of barred galaxies, because the modeled vectors form coherent structures along the bar and spiral arms. We also found a physical explanation of the problem of inconsistency between the velocity and magnetic fields character present in this type of galaxies. Due to the dynamical influence of the bar, the gas forms spiral waves which go radially outward. Each spiral arm forms the magnetic arm which stays much longer in the disk than the gaseous spiral structure. The modeled total energy of magnetic field and magnetic flux grows exponentially due to the action of the cosmic-ray driven dynamo. We also obtained the polarization maps of tidally influenced spiral galaxies which are similar to observations.

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Magnetic fields in barred galaxies

Cited by 61 publications

References 60 publications

Nonlinear magnetic diffusion and magnetic helicity transport in galactic dynamos

Nonlinear magnetic diffusion and magnetic helicity transport in galactic dynamos

Magnetic fields in our Milky Way Galaxy and nearby galaxies

3D numerical simulations of magnetic field evolution in barred galaxies and in spiral galaxies under influence of tidal forces

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