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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