Magnetic fields in spiral galaxies

Ralf-Jürgen DettmarAstronomical Institute

Ruhr-University Bochum

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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collaborators in this field are:

J. Rossa / Univ. FloridaR. Tüllmann, V. Heesen/ RUBM. Urbanik, Otmianowska-Mazur & M. Soida/ KrakovY. Shcheckinov / RostovM. Dahlem / ATNFM. Krause & R. Beck / MPIfRM. Ehle /ESA-ESAC

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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directly related to three more generalproblems:

the battery problem

the dynamo problem

the reconnection problem

M. Longair 2006 AN 327, 634

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Ferrara & McLow

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Starburst M82(Subaru Teleskop)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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M82 by

Chandra

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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„The“ Galactic chimney (DRAO)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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(Tüllmann, Bomans, Elwert, Dettmar, Ferguson A&A 2003)

magnetic field direction correlates with small scale structure in the cold interstellar medium“Crutcher-Cloud” from Galactic Plane Survey (Australia Telescope Compact Array data by McClure-Griffiths et al.)

Width ~ 0.1pc

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Dust coupled to magnetic fields? (Sofue et al.)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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sun seen withTRACE

Magnetic fields IN HALOS of spiral galaxies

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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NGC 4631: the ISM / IGM connection(Donahue et al.)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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XMM-Newton

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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NGC 4631 seen with XMM-Newton(Tüllmann, Dettmar et. al. 2006)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Effelsberg 6cm

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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NGC 7090

Dahlem & Ehle

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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XMM

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Brandenburg et al. 1992

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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from Ehle 2005

β< 1 is possible in halos

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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new 3cm data

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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from Krause & Beck 1998

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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The large scale magnetic field in spiral galaxies

the global magnetic fieldsin disk galaxiestypically have a significantpoloidalcomponent(based now on 6+ casesstudied)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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The large scale magnetic field in spiral galaxiesthe global magnetic fields in disk galaxies typically have a significant poloidalcomponent (based now on 6+ cases studied)

First „mosaic“ radio polarization image at higher frequencies (Heesen et al. 2006)

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Requires:

3D-MHD simulations of the

turbulent interstellar medium

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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Conclusions

magnetic fields in halos of spiral galaxieshave a large scale regular structure

wind vs. dynamo ?most cases studied so far have quadrupol geometry

however, small number statisticsgalactic gaseous halos have differential rotation

has to be taken into account by global models

Magnetic fields in halos of spiral galaxies

Ralf-Jürgen Dettmar @Cosmic Plasma Physics Bochum 30/31 Oct. 2006

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The End

Supported by DFG (until 31.12.2006) and DLR