Influence of star formation on galactic magnetic fields in a model with vertical structure

AbstractThe role of starburst winds versus active galactic nuclei (AGN) jets/winds in the formation of the kiloparsec scale radio emission seen in Seyferts is not yet well understood. In order to be able to disentangle the role of various components, we have observed a sample of Seyfert galaxies exhibiting kpc-scale radio emission suggesting outflows, along with a comparison sample of starburst galaxies, with the EVLA B-array in polarimetric mode at 1.4 GHz and 5 GHz. The Seyfert galaxy NGC 2639, shows highly polarized secondary radio lobes, not observed before, which are aligned perpendicular to the known pair of radio lobes. The additional pair of lobes represent an older epoch of emission. A multi-epoch multi-frequency study of the starburst-Seyfert composite galaxy NGC 3079, reveals that the jet together with the starburst superwind and the galactic magnetic fields might be responsible for the well-known 8-shaped radio lobes observed in this galaxy. We find that many of the Seyfert galaxies in our sample show bubble-shaped lobes, which are absent in the starburst galaxies that do not host an AGN.

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The generation and dissipation of solar and galactic magnetic fields

Astrophysics and Space Science ◽

10.1007/bf00647427 ◽

1973 ◽

Vol 22 (2) ◽

pp. 279-291 ◽

Cited By ~ 33

Author(s):

E. N. Parker

Keyword(s):

Magnetic Fields ◽

Galactic Magnetic Fields

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The Formation of Massive Stars

Proceedings of the International Astronomical Union ◽

10.1017/s1743921311000184 ◽

2010 ◽

Vol 6 (S270) ◽

pp. 57-64

Author(s):

Ian A. Bonnell ◽

Rowan J Smith

Keyword(s):

Star Formation ◽

Magnetic Fields ◽

Massive Star ◽

Massive Stars ◽

Cluster Formation ◽

High Mass ◽

Prestellar Cores ◽

Stellar Mergers ◽

Massive Clusters ◽

Viable Mechanism

AbstractThere has been considerable progress in our understanding of how massive stars form but still much confusion as to why they form. Recent work from several sources has shown that the formation of massive stars through disc accretion, possibly aided by gravitational and Rayleigh-Taylor instabilities is a viable mechanism. Stellar mergers, on the other hand, are unlikely to occur in any but the most massive clusters and hence should not be a primary avenue for massive star formation. In contrast to this success, we are still uncertain as to how the mass that forms a massive star is accumulated. there are two possible mechanisms including the collapse of massive prestellar cores and competitive accretion in clusters. At present, there are theoretical and observational question marks as to the existence of high-mass prestellar cores. theoretically, such objects should fragment before they can attain a relaxed, centrally condensed and high-mass state necessary to form massive stars. Numerical simulations including cluster formation, feedback and magnetic fields have not found such objects but instead point to the continued accretion in a cluster potential as the primary mechanism to form high-mass stars. Feedback and magnetic fields act to slow the star formation process and will reduce the efficiencies from a purely dynamical collapse but otherwise appear to not significantly alter the process.

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Understanding the Links among the Magnetic Fields, Filament, Bipolar Bubble, and Star Formation in RCW 57A Using NIR Polarimetry

The Astrophysical Journal ◽

10.3847/1538-4357/aa917e ◽

2017 ◽

Vol 850 (2) ◽

pp. 195 ◽

Cited By ~ 3

Author(s):

Chakali Eswaraiah ◽

Shih-Ping Lai ◽

Wen-Ping Chen ◽

A. K. Pandey ◽

M. Tamura ◽

...

Keyword(s):

Star Formation ◽

Magnetic Fields

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Submillimeter Array Observations of Magnetic Fields in Star Forming Regions

Proceedings of the International Astronomical Union ◽

10.1017/s174392131100024x ◽

2010 ◽

Vol 6 (S270) ◽

pp. 103-106

Author(s):

R. Rao ◽

J.-M. Girart ◽

D. P. Marrone

Keyword(s):

Magnetic Field ◽

Star Formation ◽

Magnetic Fields ◽

Computational Models ◽

Dominant Role ◽

Theoretical Models ◽

Mass Star ◽

Star Forming ◽

Star Forming Regions ◽

Low Mass

AbstractThere have been a number of theoretical and computational models which state that magnetic fields play an important role in the process of star formation. Competing theories instead postulate that it is turbulence which is dominant and magnetic fields are weak. The recent installation of a polarimetry system at the Submillimeter Array (SMA) has enabled us to conduct observations that could potentially distinguish between the two theories. Some of the nearby low mass star forming regions show hour-glass shaped magnetic field structures that are consistent with theoretical models in which the magnetic field plays a dominant role. However, there are other similar regions where no significant polarization is detected. Future polarimetry observations made by the Submillimeter Array should be able to increase the sample of observed regions. These measurements will allow us to address observationally the important question of the role of magnetic fields and/or turbulence in the process of star formation.

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