David Moss - Academia.edu (original) (raw)
Papers by David Moss
The Astrophysical Journal, 2009
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We study the generation and maintenance of large-scale magnetic elds in barred galaxies. We take ... more We study the generation and maintenance of large-scale magnetic elds in barred galaxies. We take a velocity eld (with strong noncircular components) from a published gas dynamical simulation of Athanassoula (1992), and use this as input to a galactic dynamo calculation. Our work is largely motivated by recent high quality VLA radio observations of the barred galaxy NGC 1097, and we compare our results in detail with the regular magnetic elds deduced from these observations. We are able to reproduce most of the conspicuous large-scale features of the observed regular eld, including the eld structure in the central regions, by using a simple mean- eld dynamo model in which the intensity of interstellar turbulence (more precisely, the turbulent diusivity) is enhanced by a factor of 2{6 in the dust lanes and near the circumnuclear ring. We argue that magnetic elds can be dynamically important, and therefore should be included in models of gas flow in barred galaxies.
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Physics of Plasmas, 1999
The possibility of dynamo action resulting from a pair of elongated vortex structures immersed in... more The possibility of dynamo action resulting from a pair of elongated vortex structures immersed in an electrically conducting fluid is investigated. For elongated vortex structures, the critical magnetic Reynolds number for dynamo action is about half that for the spherical rotors that have been studied previously. When applied to Kolmogorov turbulence with vortex structures of scale comparable to the dissipation
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Monthly Notices of the Royal Astronomical Society, 2006
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Monthly Notices of the Royal Astronomical Society, 1998
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Geophysical & Astrophysical Fluid Dynamics, 2004
... J. , 543: 1027–1043. [CrossRef], [Web of Science ®] View all references), to illustrate the s... more ... J. , 543: 1027–1043. [CrossRef], [Web of Science ®] View all references), to illustrate the scale of the relevant literature. A more systematic presentation of this literature can be found eg in a recent review by Ossendrijver (200321. Ossendrijver, M. 2003. “The stellar dynamo”. ...
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Le Journal de Physique IV, 1998
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Astronomy and Astrophysics, 2001
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Astronomy & Astrophysics, 2013
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Astronomy & Astrophysics, 2011
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Astronomy and Astrophysics, 2008
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The growth rate behavior of several kinematic dynamo models was investigated in the context of th... more The growth rate behavior of several kinematic dynamo models was investigated in the context of the observation that, as a rule, a magnetic field of a single symmetry dominates in the sun and other cosmic objects. For all dynamo models considered, it is shown that, as the dynamo numbers increase, the kinematic growth rates of fields of different parities are
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Annual Review of Astronomy and Astrophysics, 1996
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Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale... more Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The effects of star-forming regions of galaxies need to be included when modelling the evolution of their magnetic fields, which can then be compared to
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The Astrophysical Journal, 2009
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We study the generation and maintenance of large-scale magnetic elds in barred galaxies. We take ... more We study the generation and maintenance of large-scale magnetic elds in barred galaxies. We take a velocity eld (with strong noncircular components) from a published gas dynamical simulation of Athanassoula (1992), and use this as input to a galactic dynamo calculation. Our work is largely motivated by recent high quality VLA radio observations of the barred galaxy NGC 1097, and we compare our results in detail with the regular magnetic elds deduced from these observations. We are able to reproduce most of the conspicuous large-scale features of the observed regular eld, including the eld structure in the central regions, by using a simple mean- eld dynamo model in which the intensity of interstellar turbulence (more precisely, the turbulent diusivity) is enhanced by a factor of 2{6 in the dust lanes and near the circumnuclear ring. We argue that magnetic elds can be dynamically important, and therefore should be included in models of gas flow in barred galaxies.
Bookmarks Related papers MentionsView impact
Physics of Plasmas, 1999
The possibility of dynamo action resulting from a pair of elongated vortex structures immersed in... more The possibility of dynamo action resulting from a pair of elongated vortex structures immersed in an electrically conducting fluid is investigated. For elongated vortex structures, the critical magnetic Reynolds number for dynamo action is about half that for the spherical rotors that have been studied previously. When applied to Kolmogorov turbulence with vortex structures of scale comparable to the dissipation
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Monthly Notices of the Royal Astronomical Society, 2006
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Monthly Notices of the Royal Astronomical Society, 1998
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Geophysical & Astrophysical Fluid Dynamics, 2004
... J. , 543: 1027–1043. [CrossRef], [Web of Science ®] View all references), to illustrate the s... more ... J. , 543: 1027–1043. [CrossRef], [Web of Science ®] View all references), to illustrate the scale of the relevant literature. A more systematic presentation of this literature can be found eg in a recent review by Ossendrijver (200321. Ossendrijver, M. 2003. “The stellar dynamo”. ...
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Le Journal de Physique IV, 1998
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Astronomy and Astrophysics, 2001
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Astronomy & Astrophysics, 2013
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Astronomy & Astrophysics, 2011
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Astronomy and Astrophysics, 2008
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The growth rate behavior of several kinematic dynamo models was investigated in the context of th... more The growth rate behavior of several kinematic dynamo models was investigated in the context of the observation that, as a rule, a magnetic field of a single symmetry dominates in the sun and other cosmic objects. For all dynamo models considered, it is shown that, as the dynamo numbers increase, the kinematic growth rates of fields of different parities are
Bookmarks Related papers MentionsView impact
Annual Review of Astronomy and Astrophysics, 1996
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Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale... more Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The effects of star-forming regions of galaxies need to be included when modelling the evolution of their magnetic fields, which can then be compared to
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